New Directions in Behavioral Activation

Home , Behavioral activation, Charles Ferster, Reward system

Clinical Psychology Review 79 (2020) 101860

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Clinical Psychology Review

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Review New directions in behavioral activation: Using findings from basic science T and translational neuroscience to inform the exploration of potential mechanisms of change Courtney N. Forbes

Department of Psychology, University of Toledo, Mail Stop 948, 2801 West Bancroft Street, Toledo, OH 43606, USA

HIGHLIGHTS

• Understanding mechanisms of change can facilitate improvements in BA treatments. • BA treatments may work by targeting (low) reward responsiveness directly. • Basic science findings can inform hypotheses about potential mechanisms of change.

ARTICLE INFO ABSTRACT

Keywords: Interest in behavioral activation treatments for depression has increased over the past two decades. Behavioral Behavioral activation activation treatments have been shown to be effective in treating depression across a variety of populations and Reward responsiveness settings. However, little is known about the mechanisms of change that may bring about symptom improvement Depression in behavioral activation treatments. Recent developments in the theoretical and empirical literature on beha- Mechanisms of change vioral activation treatments have coincided with advances in basic science and translational neuroscience re- Translational neuroscience garding the mechanisms underlying individual differences in responsiveness to reward. Attenuated reward responsiveness has been associated with depression and related clinical outcomes at the self-report, behavioral, and neural levels of analysis. Given that behavioral activation treatments are focused on increasing individuals' contact and engagement with sustainable sources of reward in their environment, it is plausible that behavioral activation treatments bring about improvements in depression symptoms by targeting (low) reward responsiveness directly. This paper integrates findings from the clinical research literature on behavioral activation treatments with insights drawn from basic science and translational neuroscience in order to propose hypotheses about potential mechanisms of change in behavioral activation. Conceptual issues and recommendations for future research on behavioral activation treatments are discussed.

1. Introduction et al., 1996) of cognitive-behavioral therapy for depression (CBT; Beck, Rush, Shaw, & Emery, 1979) demonstrated that the behavioral activa- The past two decades have seen a resurgence of interest in treat- tion (BA) component of CBT was as efficacious as the full CBT package ments that are rooted in behavioral and contextual theories of psy- in improving depression symptoms and preventing depression relapse chopathology. Behavioral and contextual theories emphasize the in- for up to two years following the initial treatment (Gortner, Gollan, fluence of idiographic contextual factors, such as the environmental Dobson, & Jacobson, 1998). Results of the component analysis study antecedents and consequences of behavior, on the development and inspired the development of several novel BA treatments (e.g., Lejuez, maintenance of psychological disorders (Ferster & Skinner, 1957; Hopko, Acierno, Daughters, & Pagoto, 2011; Lejuez, Hopko, & Hopko, Jacobson, 1994; Skinner, 1953). In particular, there has been a renewed 2001; Martell, Addis, & Jacobson, 2001) based on this parsimonious interest in behavioral activation treatments for depression, which focus approach. These BA treatments have been shown to be effective for primarily on increasing individuals' engagement with “rewarding” ac- treating depression across a variety of populations and settings. tivities; that is, sustainable sources of positive reinforcement in their The renewed interest in the development and dissemination of BA environment. In the late 1990s, a component analysis study (Jacobson treatments over the past several decades has occurred concurrently

E-mail address: [email protected]. https://doi.org/10.1016/j.cpr.2020.101860 Received 25 December 2019; Received in revised form 3 March 2020; Accepted 1 May 2020 Available online 05 May 2020 0272-7358/ © 2020 Elsevier Ltd. All rights reserved. C.N. Forbes Clinical Psychology Review 79 (2020) 101860 with advances in basic science and translational neuroscience research Furthermore, this review builds upon Nagy et al.'s (2020) work by on biobehavioral mechanisms underlying psychological disorders. One conceptualizing relations between basic science findings on reward mechanism of particular relevance to depression and other disorders functioning and BA treatment strategies within the framework of spe- characterized by attenuated motivation and positive affect is respon- cific Positive Valence Systems (PVS) sub-domains. siveness to rewarding stimuli, which is thought to be driven by dopaminergic activity in the brain's mesolimbic pathway (Nestler & 2. Early models of reward functioning in depression: Gray, Carlezon, 2006). The neural reward system is thought to govern goal- Ferster, and Lewinsohn directed behavior related to seeking out primary rewards, such as food and sex; as well as secondary rewards, such as monetary gain and po- Individual differences in reward-seeking behavior and responsive- sitive social feedback (Arias-Carrión, Stamelou, Murillo-Rodríguez, ness to reward have long been recognized. The Reinforcement Menéndez-González, & Pöppel, 2010). Thus, the reward system is Sensitivity Theory of Personality (RST; Gray, 1972, 1990) proposes that thought to play a critical role in human motivation as well as hedonic behavior is influenced by two primary motivational systems: thebe- enjoyment of rewards (Berridge & Robinson, 2003). Abnormalities in havioral activation system (BAS) and the behavioral inhibition system the functioning of this system, which governs behavioral responsiveness (BIS). The BAS is thought to govern reward sensitivity (i.e., interest in to positive stimuli (i.e., reward functioning), have been associated with and responsiveness to reward) and approach motivation. Atypically low symptoms of major depressive disorder (MDD) including reductions in functioning of the BAS and other personality constructs related to po- motivation, activity level, and the ability to experience pleasure sitive emotionality (e.g., positive affect, extraversion) has been asso- (Treadway & Zald, 2011). ciated with depression symptom severity cross-sectionally and long- The activity of the reward system may be particularly relevant to BA itudinally across a variety of populations, and has been shown to treatments for depression, given that the primary emphasis of BA predict the maintenance of depression symptoms over time (Kasch, treatments is on increasing patients' activity level and engagement with Rottenberg, Arnow, & Gotlib, 2002; McFarland, Shankman, Tenke, rewarding activities. Robust associations have been observed between Bruder, & Klein, 2006; see Khazanov & Ruscio, 2016, for a meta-ana- depression and attenuated reward functioning (Pizzagalli et al., 2009; lysis). In addition to highlighting associations between reward func- Smoski et al., 2009; Treadway, Bossaller, Shelton, & Zald, 2012). By tioning and depression, Gray's work has influenced the development of increasing patients' contact with rewarding stimuli, BA treatments may contemporary conceptualizations of approach motivation in relation to bring about improvements in depression symptoms by targeting (low) the PVS domain (Olino, McMakin, & Forbes, 2018), and is reflected in reward functioning directly. However, research on mechanisms of PVS sub-domains including Reward Anticipation, Initial Responsive- change in BA treatments has been limited. Despite their conceptual ness, and Effort Valuation. overlap, the literature on the efficacy of BA treatments has, for the most Theoretical understanding of the role of approach motivation in part, developed independently of basic science and translational neu- depression was advanced by a seminal behavioral theory proposed by roscience research on biobehavioral processes involved in reward Charles Ferster (1973, 1974), a colleague of B.F. Skinner's who applied functioning. the principles of radical behaviorism (Skinner, 1953, 1957) to a func- The purpose of this paper is to integrate the clinical literature on BA tional analysis of behaviors associated with depression. Specifically, treatments with research on biobehavioral processes involved in reward Ferster proposed that behaviors associated with depression are driven functioning in order to use insights from basic science and translational by both positive reinforcement, or the presentation of a positive sti- neuroscience research to inform hypotheses about potential mechan- mulus following a behavior; and negative reinforcement, or the removal isms of change in BA treatments. The development of novel hypotheses of an aversive stimulus following a behavior. Ferster observed that in- informed by basic science may pave the way for future research focused dividuals with depression often exhibit a reduction in overall activity on identification of the mechanisms in BA treatments that drive level, which may be influenced by the absence of positive reinforce- symptom change. Increased knowledge of these mechanisms of change ment for adaptive behaviors in work, social relationships, and other life may, in turn, facilitate the development and refinement of future BA domains. Ferster also suggested that depression is associated with an treatments. increase in the frequency of avoidance and escape behaviors, which The need for greater understanding of mechanisms of change in function to decrease contact with aversive stimuli such as distressing reward-focused treatments is highlighted by recent findings that situations and/or undesired emotions. Furthermore, Ferster posited that widely-used treatments for depression, including CBT and anti- an increase in the frequency of avoidance behaviors may interfere with depressant medications, may have limited efficacy in treating low po- an individual's ability to access sources of positive reinforcement in sitive affect and anhedonia. In a recent analysis of two randomized their environment. For example, if an individual chooses not to attend a controlled trials of CBT, antidepressant medications, and a combination concert with friends because they anticipate that the event will be loud, of both treatments (Dunn et al., 2019), there was less improvement in tiring, and uncomfortable, they might lose the opportunity to experi- positive (vs. negative) affect from pre- to post-treatment across trials ence positive consequences, such as enjoyment of time with friends. and treatment conditions. Moreover, positive affect was more likely to Similarly, if an individual chooses not to take on a challenging project remain below general population levels following either course of at work out of a concern that it will require too much effort, they might treatment. These findings suggest that new treatment approaches are miss out on the opportunity to experience a sense of mastery upon needed to target low positive affect and anhedonia. Elucidating the completing the project. mechanisms driving symptom change in reward-focused treatments Consistent with Hernstein's (1961, 1970) Matching Law, which may shed light on new strategies for addressing these difficult-to-treat posits that the frequency of a particular behavior is directly propor- symptoms (McMakin et al., 2012; Uher et al., 2012). tional to the relative value of reinforcement obtained for that behavior, Nagy et al. (2020) presented a review of the theoretical bases of BA Ferster suggested that the frequency of “depressed” behaviors (e.g., treatments, as well as evidence supporting the relevance of reward staying in bed, turning down social invitations) and “non-depressed” functioning to clinical outcomes in BA. Based on this review and with behaviors (e.g., participating in hobbies, engaging with work, seeking the intention of translating research on reward functioning into clinical out social activities) are directly proportional to the relative value of practice, Nagy et al. (2020) proposed a novel, transdiagnostic treatment reinforcement obtained for each type of behavior. The relative value of for anhedonia (Behavioral Activation Treatment for Anhedonia; BATA). reinforcement (i.e., its accessibility, duration, and immediacy) for a The present review extends Nagy et al.'s (2020) work by highlighting “depressed” behavior, such as staying in bed, may be increased when it concrete pathways through which BA treatment strategies – including is easily accessible and results in an immediate reduction in distress. those proposed in BATA – may bring about symptom improvement. With a higher relative value of reinforcement, the frequency of the

2 C.N. Forbes Clinical Psychology Review 79 (2020) 101860 behavior of staying in bed is likely to increase. Likewise, the relative training, and problem-solving skills were incorporated into the treat- value of reinforcement for a “non-depressed” behavior, such as in- ment (Brown & Lewinsohn, 1984; Lewinsohn, Sullivan, & Grosscup, itiating conversations with a romantic partner, may decrease if there is 1980). Approaches drawn from Lewinsohn and colleagues' behavioral a lack of positive reinforcement for the behavior (e.g., if the partner treatment were also incorporated into cognitive-behavioral treatments, does not engage in conversation once it is initiated). With a lower re- such as CBT for depression (Beck et al., 1979), which gained popularity lative value of reinforcement, the behavior is likely to decrease in fre- in the 1970s and 1980s. In the late 1990s, however, results of a com- quency. With this in mind, Ferster and others (e.g., McDowell, 1982) ponent analysis study of CBT for depression (Jacobson et al., 1996) suggested that depression persists when there is a low relative value of demonstrated that the more parsimonious BA component of CBT was as reinforcement for “non-depressed” behaviors and a relatively high efficacious in improving depression symptoms as the full CBT package, value of reinforcement for “depressed” behaviors. which also includes the identification of maladaptive core beliefs, Around the same time, Peter Lewinsohn and colleagues (e.g., challenging of automatic thoughts, cognitive restructuring, and training Lewinsohn & Graf, 1973) proposed a behavioral explanation of the in social skills, problem-solving skills, and relaxation techniques. onset and maintenance of depression. Their theory suggested that de- The finding that BA alone could improve symptoms as muchas pression results from a low rate of response-contingent positive re- more complex and time-intensive CBT treatments led to a renewed inforcement (RCPR) for “non-depressed” behaviors related to work, interest in BA as a stand-alone intervention. Two BA treatments de- relationships, and other life domains. Lewinsohn and colleagues hy- veloped in the early 2000's have received extensive empirical support: pothesized that the onset of depression may result from chronically low Behavioral Activation (Martell et al., 2001) and Brief Behavioral Acti- levels of RCPR; or may follow an event that deprives an individual of an vation Treatment for Depression (BATD; Lejuez et al., 2001, 2011). important source of reinforcement, such as the death of a spouse, loss of Given that the term “Behavioral Activation” may refer to the broad a job, or loss of physical ability due to an illness or injury. For example, category of behavioral activation treatments as well as Martell et al.'s an individual who has recently lost a spouse may experience a decrease (2001) treatment, the acronym “BA” will be used to refer to the broad in RCPR for behaviors such as cooking dinner and doing household category of BA treatments, and the term “Behavioral Activation” will be chores, because the positive consequence of spending time with their used to refer to Martell et al.'s (2001) treatment in particular. spouse associated with these activities has been removed. Lewinsohn and colleagues suggested that the frequency of “non-depressed” beha- 3.1. Behavioral activation viors would decrease as a function of reduced or nonexistant positive reinforcement for these behaviors. The severity of depression was A primary goal of Behavioral Activation (Martell et al., 2001) is to thought to be proportional to (low) levels of RCPR. By extension, in- increase patients' engagement in rewarding activities, with a particular creasing RCPR was thought to bring about a reduction in depression focus on disrupting patterns of avoidance and escape behavior that symptoms. limit opportunities to engage with environmental sources of positive Based on this model, Lewinsohn and colleagues developed the reinforcement. As in Ferster (1973, 1974) and Lewhinsohn's Pleasant Events Schedule (PES; MacPhillamy & Lewinsohn, 1971), a list (Lewinsohn & Graf, 1973) models, “depressed” behaviors are thought to of 320 activities that were thought to be positively reinforcing, which function as avoidance and escape strategies. Therefore, there is an became the basis of a novel treatment for depression (Lewinsohn & emphasis on increasing patients' awareness of the consequences of Graf, 1973). At the outset of this treatment, patients were instructed to avoidance-oriented coping behaviors. The acronym TRAP (Trigger, rate the pleasantness of each PES item on a 3-point scale, and then to Response, Avoidance Pattern) is used to illustrate a pattern of avoid- identify the 160 activities rated as most pleasant. Patients were sub- ance behavior that may contribute to the maintenance of depression. sequently instructed to engage in activities they identified as pleasur- For example, a person might receive negative feedback on a project at able, and to maintain a record of their activities and mood each day. work (Trigger), which precipitates feelings of frustration and shame The utility of the PES received empirical support; for example, in a (Response). Consequently, they might choose to call in sick to work and study of 90 undergraduates including currently depressed participants, stay in bed the next day (Avoidance Pattern). Although the behavior of psychiatric controls, and nonpsychiatric controls, less engagement in calling in sick to work and staying in bed is likely to alleviate distress in pleasant activites was significantly associated with low mood across all the short-term, it may also lead to work-related problems. Moreover, three groups over a 30-day period; and depressed participants were this behavior limits opportunities for positive reinforcement, such as found to engage in significantly fewer pleasant activities overall com- accomplishing a different task at work. pared to psychiatric and nonpsychiatric controls (Lewinsohn & Graf, Once ineffective coping strategies are identified, the next step isto 1973). disrupt patterns of avoidance behavior through the use of alternative Several key concepts from Ferster and Lewinsohn's work laid the coping behaviors. The acronym TRAC (Trigger, Response, Alternative foundations for the development of novel BA treatments several dec- Coping) illustrates this process. Extending the example above, the in- ades later. Both Ferster and Lewinsohn conceptualized depression as dividual who received negative feedback on a project (Trigger) and driven, in part, by low levels of RCPR. Both scholars suggested that a experienced a negative emotional response (Response) might reflect on low rate of RCPR for “non-depressed” behaviors is likely to decrease the the negative feedback and make a plan for improving their performance frequency of those behaviors; and a high rate of negative reinforcement on future projects (Alternative Coping). The use of alternative coping for “depressed” behaviors (e.g., avoidance and escape behaviors) would strategies is thought to interrupt the feedback loop of avoidance be- likely increase the frequency of these behaviors. Furthermore, increases havior and worsening depression by identifying opportunities to ad- in avoidance and escape behaviors were thought to narrow individuals' dress and modify environmental precipitants of avoidance. A reduction opportunities to engage with environmental sources of RCPR. The in avoidance coping, in turn, is thought to bring about increased op- combination of decreases in “non-depressed” behaviors and increases in portunities for engagement with environmental sources of reward. “depressed” behaviors were thought to reduce contact with sources of Behavioral Activation prioritizes the identification of activities that RCPR; and this in turn was thought to bring about symptom worsening. patients find enjoyable. The therapist and patient work together to generate a list of positively reinforcing activities, and then prioritize the 3. Current empirically supported BA treatments activities and break them down into manageable components. The therapist and patient then develop concrete, specific plans for engaging Over time, the pleasant event scheduling intervention (Lewinsohn & in those activities. Patients are instructed to engage in activities during Graf, 1973) shifted away from a purely behavioral approach as strate- the week and monitor any mood changes that occur as a result. Through gies such as cognitive restructuring, relaxation training, assertiveness “graded task assignment,” patients gradually increase their level of

3 C.N. Forbes Clinical Psychology Review 79 (2020) 101860 activity over the course of treatment. Over time, reductions in avoid- residential substance abuse treatment (Daughters et al., 2008). BA treat- ance behavior and increases in approach-oriented coping strategies are ments have also been adapted to different treatment modalities, including thought to facilitate engagement with sources of reward and subgroup therapy (Chu et al., 2016; Hershenberg, Smith, Goodson, & Thase, sequent improvement in depression symptoms (Martell et al., 2001). 2018), internet-delivered treatments (see Huguet et al., 2018, for a review), one-session interventions (Tull, Berghoff, Bardeen, Schoenleber, & 3.2. Brief behavioral activation treatment for depression Konkle-Parker, 2018), and delivery by primary care paraprofessionals (Ekers, Dawson, & Bailey, 2013; Ekers, Richards, McMillan, Bland, & Similar to Behavioral Activation, Brief Behavioral Activation Gilbody, 2011). Strategies from BA have also been incorporated into other Treatment for Depression (BATD; Lejuez et al., 2001, 2011) emphasizes empirically supported treatments, such as exposure therapy for PTSD increasing patients' engagement with sources of RCPR in their en- (Acierno et al., 2016). vironment. The theoretical foundations of BATD are informed by Notably, Jacobson et al.'s (1996) finding that the BA component of Hernstein's (1961, 1970) Matching Law and Ferster's (1973) behavioral CBT was comparable to the full CBT package in improving depression theory of depression, which suggest that the frequency of “depressed” symptoms has been extended in several recent studies. A recent re- and “non-depressed” behaviors exhibited by an individual will be di- analysis of Jacobson et al.'s (1996) outcome data found that there were rectly proportional to the relative value of reinforcement obtained for no significant differences in treatment outcomes between the BA-only those behaviors. Thus, the treatment employs strategies for increasing group and full-CBT group when only individuals with severe depression the relative value of reinforcement for “non-depressed” behaviors, with (Hamilton Rating Scale for Depression score ≥ 20) were included in the intention of increasing the frequency of these behaviors; and de- analyses (Lorenzo-Luaces & Dobson, 2019). These findings are con- creasing relative value of reinforcement for “depressed” behaviors, with sistent with Jacobson et al.'s (1996) results; however, they failed to the goal of decreasing the frequency of these behaviors (Lejuez et al., replicate Dimidjian et al.'s (2006) finding that BA is more efficacious 2001, 2011). Given that BATD is focused almost exclusively on mod- than CBT for severe depression. By contrast, other studies have de- ifying behavior, the treatment is straightforward and transportable, monstrated that BA alone facilitates greater symptom improvemement which has facilitated its application across different populations and than CBT. For example, a recent 12-week clinical trial of CBT for settings (Lejuez et al., 2011). adolescent females with depression (Webb et al., 2019) found that BATD is typically administered over 8–15 sessions in a highly patients' engagement in the BA component of CBT was a significant structured format, with specific activities assigned to be completed predictor of session-by-session symptom changes, while patients' self- during and in-between weekly individual therapy sessions. At the outset rated use of cognitive skills did not significantly predict symptom im- of treatment, patients use self-monitoring strategies to establish a provement. These somewhat conflicting findings highlight the need for baseline activity level. The therapist and patient then work together to a more nuanced understanding of the processes underlying symptom identify behavioral goals related to the patient's personal values in life change in BA treatments. domains including relationships, education, employment, hobbies, and physical health. Longer-terms goals are broken down into specific ac- 5. What's next? Mechanisms of change in behavioral activation tion steps, and behaviors are then ranked according to their perceived difficulty in order to create a hierarchy from least to most challenging Despite robust empirical support for the efficacy of BA treatments, behaviors. During individual therapy sessions, concrete plans are de- there has been a surprising lack of research on specific mechanisms of veloped for activities to be completed during the week. Patients use change that may bring about symptom improvement. Research on monitoring forms to track their activities throughout the week. mechanisms of change is critical for the development and refinement of Monitoring forms are reviewed in subsequent sessions, and barriers that psychological treatments (Kazdin, 2005), given that identifying these may have interfered with the completion of assigned activities are mechanisms can help researchers and clinicians determine which discussed. Next, activities are planned for the following week, and the components of a treatment are causally related to symptom improve- therapist and patient problem-solve potential barriers to engagement. ment. A small number of studies have examined factors that may drive The amount and/or difficulty of assigned activities gradually increases symptom change in BA treatments. One participant-level study of four each week, with the ultimate goal of building sustainable patterns of depressed adolescents who demonstrated remission following BA engagement with rewarding activities that will persist after the end of treatment (Gaynor & Harris, 2008) found that increases in activity level treatment (Lejuez et al., 2001, 2011). A key assumption of BATD is that over the course of treatment were followed by improvements in de- new skills are developed and practiced most effectivly in the patient's pression symptoms. Furthermore, in an open-label trial of BA adapted environment while they are engaging in rewarding activities. There- for Spanish-speaking Latinx individuals (N = 10; Collado, Castillo, fore, rather than teaching coping skills prior to increasing a patient's Maero, Lejuez, & MacPherson, 2014), improvements in depression activity level, skill and performance deficits related to specific beha- symptoms were found to occur concurrently with increases in activity viors are problem-solved during weekly sessions (Hopko, Lejuez, level. In a session-by-session analysis of 21 Latinx individuals receiving Ruggiero, & Eifert, 2003). the intervention described above (Santos et al., 2017), increases in activity level preceded or co-occurred with changes in depression for a 4. Effectiveness of BA treatments across varied populations and majority of participants. Consistent with these preliminary findings, settings results from a trial of BATD among 23 depressed cancer patients (Ryba, Lejuez, & Hopko, 2014) demonstrated that greater engagement in as- There is abundant support for the efficacy of BA treatments (Lejuez signed activities accounted for substantial improvements in depression et al., 2001, 2011; see meta-analyses by Cuijpers, Van Straten, & symptoms over the course of treatment. In the same study, all patients Warmerdam, 2007; Ekers et al., 2014; and Mazzuchelli, Kane, & Rees, who compled 100% of assigned activities achieved remission of a de- 2009). BA treatments have been found to improve depression symptoms in pressive episode by the end of the 8-week treatment. These studies a variety of populations, including veterans (Wagner, Jakupcak, Kowalski, provide preliminary indications that increases in activity level may lead Bittinger, & Golshan, 2019), cancer patients (Hopko, Magidson, & Lejuez, to symptom improvement in BA treatments. However, relations be- 2011; Hopko, Robertson, & Carvalho, 2009), Latinx (Kanter et al., 2015) tween activity level and symptom change would need to be observed in and African-American (Jacob, Keeley, Ritschel, & Craighead, 2013) po- larger and more diverse samples in order to further validate these pulations, children and adolescents (see Martin & Oliver, 2019, for a re- findings. Given the small number of studies on mechanisms of changein view), pregnant women (Dimidjian et al., 2017), psychiatric inpatients BA, there is a need for further examination of mechanisms that could (Hopko, Lejuez, Lepage, Hopko, & McNeil, 2003), and drug users in inform the development and refinement of future BA interventions.

4 C.N. Forbes Clinical Psychology Review 79 (2020) 101860

6. Reward functioning days (Reward Satiation). Finally, the person might learn from this experience that hard work is likely to lead to a promotion, and might then As noted above, a potential mechanism of change in BA that war- apply similar strategies in the pursuit of other work-related rewards in rants attention is improvement in reward functioning. Given that the the future (Reward Learning). primary goal of BA treatments is to increase individuals' engagement Basic science findings related to several sub-domains of reward with rewarding stimuli in their environment, BA may bring about functioning will be reviewed below. In particular, Reward Anticipation, symptom improvement by increasing individuals' engagement in and Initial Responsiveness, Effort Valuation, and Reward Learning will be responsiveness to rewarding stimuli. Reward functioning is a multi- discussed in relation to potential mechanisms of change in BA treat- faceted construct that captures individuals' tendencies to seek out, an- ments. Recent findings on distinctions among sub-types of reward ticipate, and respond to rewarding stimuli; as well as the willingness to functioning that may be relevant to BA treatments will also be con- expend effort to obtain rewards and the ability to modify behavior in sidered. response to shifting environmental reward contingencies (Gard, Gard, Kring, & John, 2006; Pizzagalli, Jahn, & O'Shea, 2005; Treadway, 7. Potential reward-related mechanisms of change in behavioral Buckholtz, Schwartzman, Lambert, & Zald, 2009; Whitton, Treadway, & activation Pizzagalli, 2015). In recent decades, research on neural and behavioral processes related to reward functioning has shed new light on the role To date, one study has examined changes in neural reward func- of this mechanism in the etiology and maintenance of depression tioning over the course of BA treatment (Dichter et al., 2009). Twenty- (Treadway & Zald, 2011). In particular, research on reward functioning seven adults with and without MDD completed a behavioral Wheel of has been advanced by the identification of two relevant neural circuits. Fortune task, which parses the anticipation, selection, and feedback The first, a ventral (limbic) neurocircuit that includes the amygdala, phases of reward, while undergoing functional magnetic resonance insula, ventral striatum, and ventral regions of the anterior cingulate imaging (fMRI). Participants with MDD subsequently received 8–14 cortex and orbitofrontal cortex, is involved in assigning emotional weekly individual sessions of BATD. Relative to controls, depressed salience to stimuli and generating affective responses. The second, a participants who received BATD demonstrated increased functional dorsal (cognitive) neurocircuit that includes the hippocampus, dorsal responding in the dorsal striatum during anticipation of reward, the regions of the anterior cingulate cortex, and the parietal cortex, is in- paracingulate gyrus during selection of reward, and the paracingulate volved in selective attention, planning, and effortful regulation of and orbitofrontal gyri while receiving feedback about the amount of emotions (Nusslock & Alloy, 2017; Phillips, Drevets, Rauch, & Lane, reward obtained. Findings from this preliminary study raise the possi- 2003a; Phillips, Drevets, Rauch, & Lane, 2003b). Attenuated activation bility that BA treatments may increase the activation of neural circuits in these circuits has been linked to depression-relevant outcomes. Re- relevant to reward functioning. However, there is a need for further cent findings point to attenuated fronto-striatal responding to reward as research on the influence of BA treatments on this mechanism, as well an endophenotypic marker that signals risk for MDD among youth with as whether increased neural reward functioning leads to subsequent a family history of depression (Gotlib et al., 2010; Olino et al., 2014), symptom improvement. distinguishes individuals with depression from nondepressed controls (Epstein et al., 2006), and predicts increases in depression symptoms 7.1. Anticipatory versus consummatory reward functioning over time (Morgan, Olino, McMakin, Ryan, & Forbes, 2013). Recognizing the importance of reward functioning as a broad do- One line of research has focused on temporal components of reward main underlying psychological functioning at multiple levels of analysis functioning. Researchers have distinguished between reward anticipa- (e.g., neural, behavioral, self-report), the National Institute of Mental tion, or the desire for and pleasant anticipation of a reward, and con- Health (NIMH) included a PVS domain in its Research Domain Criteria sumption, or enjoyment of a reward in-the-moment (Klein, 1984; framework (RDoC; Insel et al., 2010). The PVS domain encompasses Knutson, Adams, Fong, & Hommer, 2001). Although this research several sub-domains of reward functioning (NIMH, 2018; PVS predates the PVS domain, these constructs would align with Reward Proceedings, 2011): 1) Reward anticipation, which reflects anticipation Anticipation and Initial Responsiveness. The distinction between re- of reward; 2) Initial responsiveness, which reflects in-the-moment reward anticipation and consumption was informed by preclinical responseiveness to reward; 3) Reward satiation, which reflects longer- search conducted in animals, which showed that “wanting” and “liking” term responseiveness to reward; 4) Reward learning, which refers to the are associated with different brain structures and patterns of neuro- ability to adapt reward-seeking behavior in response to changing con- chemical activity (Berridge & Robinson, 2003). “Wanting” is associated tingencies; 5) Reward probability, which reflects expectations about the with dopamine systems involved in assigning salience to rewards, while probability of obtaining a reward; 6) Delay, which reflects the ability to “liking” is associated with opioid, endocannabinoid, and GABA neuro- integrate information about the time interval prior to the delivery of a transmitter systems involved in pleasurable reactions to reward. reward into reward-seeking behavior; and 7) Effort valuation, which Several studies have used the Temporal Experience of Pleasure Scale, a reflects willingness to expend effort to obtain a reward. self-report measure of anticipatory and consummatory components of To illustrate the relevance of each PVS category to reward attain- reward functioning (Gard et al., 2006), to examine temporal compo- ment, imagine a situation in which a person could potentially receive a nents of reward functioning. Results have identified attenuation in self- promotion based on their performance on an important project at work. reported reward anticipation among individuals with depression The person might estimate that the likelihood of receiving a promotion (Chentsova-Dutton & Hanley, 2010) and schizophrenia (Gard, Kring, is high if the project is successful (Reward Probability). They might Gard, Horan, & Green, 2007). There were not significant differences in decide that it is worthwhile to spend extra time working on the project consummatory reward functioning, however, between clinical popula- during the evenings and over the weekend, based on the assumption tions and nonclinical controls. Relatedly, associations between antici- that doing so will increase the probability of receiving the promotion pation of reward and personality traits associated with depression (i.e., (Effort Valuation). Moreover, they may be willing to maintain thisad- low approach motivation and positive emotionality) have been found to ditional effort for several months if they perceive the promotion tobe be stronger than associations between reward consumption and the highly desirable (Delay). Following successful completion of the pro- same measures (Ho, Cooper, Hall, & Smillie, 2015), suggesting that low ject, the person might look forward in anticipation to receiving the reward anticipation may be particularly relevant to depression. promotion (Reward Anticipation). When they receive good news about Temporal components of reward functioning have also been ex- the promotion, they might experience a positive emotional response in amined at the behavioral level of analysis. In one study, currently de- the moment (Initial Responsiveness) that persists over the next several pressed, previously depressed, and never-depressed undergraduates

5 C.N. Forbes Clinical Psychology Review 79 (2020) 101860 completed a puzzle-solving task for monetary reward (McFarland & between activities and resulting mood changes (see discussion of Klein, 2009). Consistent with findings from self-report studies, de- Reward Learning, below). Furthermore, strategies to increase mindful pressed participants evidenced the lowest levels of reward anticipation awareness may help patients connect with natural contingencies asso- during the puzzle-solving task. In another study, adults with a range of ciated with engaging in rewarding activities (Jacobson et al., 1996). In depression symptoms completed a task in which they were required to other words, mindfulness may increase the positive emotional con- expend effort to view enjoyable cartoons (Sherdell, Waugh, & Gotlib, sequences of engaging in rewarding activities by drawing an in- 2012). Results indicated that participants with low reward anticipation dividuals' focus toward enjoyable aspects of an activity, and perhaps were significantly less willing to expend effort in order to viewthe away from perseverative thoughts that might otherwise limit engage- cartoons. There were no differences, however, between depressed and ment. non-depressed participants in their in-vivo enjoyment of the cartoons. Finally, among nonclinical university students, low reward anticipation 7.2. Willingness to expend effort for rewards was associated with weaker affective responses to a positive emotion induction and less willingness to expend effort on a behavioral task Another key component of reward functioning is effort valuation, or (Geaney, Treadway, & Smillie, 2015). These effects were not observed the willingness to expend effort in order to obtain a reward. Extending for reward consumption. These results are consistent with findings from preclinical research on effort-based decision-making in rodents (Correa, self-report studies suggesting that reward anticipation may be espe- Carlson, Wisniecki, & Salamone, 2002; Salamone, Correa, Farrar, & cially relevant to depression, while reward consumption may be less Mingote, 2007), Treadway et al. (2009) developed the Effort Ex- disrupted among depressed individuals. penditure for Rewards Task (EEfRT) in order to assess effort-based Several recent neuroimaging studies have contributed to the decision-making in a laboratory setting. During the task, participants growing base of knowledge regarding associations between depression choose between performing high-effort or low-effort tasks to obtain and temporal components of reward functioning. In a recent meta- varying amounts of monetary reward. However, monetary reward is not analysis of fMRI studies examining reward processing abnormalities in provided for all tasks. Instead, participants are informed during each depression, reduced striatal activation during reward anticipation was trial of the probability that the monetary reward will be provided fol- shown to distinguish individuals with depression from non-depressed lowing task completion. Thus, individuals' choices on the task take into controls (Keren et al., 2018). Moreover, in a large study (N = 1576) of account the influence of the amount of effort required for the task,the community adolescents (Stringaris et al., 2015), low ventral striatal value of the potential monetary reward, and the probability that the activation during reward anticipation in a laboratory-based monetary reward will be provided upon completion of the task. In the initial reward task (Knutson et al., 2001) differentiated individuals with sub- validation sample (Treadway et al., 2009), which included adults threshold and clinical depression from non-depressed controls, pre- screened to ensure a range of trait anhedonia scores, trait anhedonia dicted the transition to subthreshold or clinical depression at two-year was significantly and negatively associated with the proportion of high- follow-up, and demonstrated stronger associations with the symptom of effort tasks selected for medium probability trials. Moreover, depres- anhedonia relative to low mood. sion symptoms were significantly and negatively associated with the In summary, observations from multiple levels of analysis suggest proportion of high-effort tasks selected for high probability trials. In that the processes underlying reward anticipation and consumption are other words, individuals with higher levels of anhedonia and other related to depression, and are to some extent separable. This distinction depression symptoms tended to choose fewer high-effort tasks in trials is relevant to BA treatments, as it may shed light on antecedent barriers where there was a medium or high probability of obtaining a monetary and reinforcing contingencies that influence individuals' choices to reward. engage in potentially rewarding activities. In particular, findings from a Subsequent studies using the EEfRT task have confirmed associa- number of studies indicate that reward anticipation tends to be more tions between depression and attenuated willingness to expend effort impaired than reward consumption among individuals with depression. for rewards. In a sample of adults with and without MDD (Treadway Therefore, attenuated reward anticipation may serve as an antecedent et al., 2012), participants with MDD selected a significantly lower barrier to engagement in meaningful and enjoyable activities. Patients proportion of high-effort tasks compared to participants without MDD. with low reward anticipation may feel as though there is “nothing good Moreover, in the MDD group, the selection of low-effort tasks was to look forward to,” or that there would be “no point” to an activity. For significantly associated with the length of the current depressive epi- example, a patient who is thinking about getting involved in vo- sode, suggesting that the willingness to expend effort for reward may be lunteering for a community organization might experience thoughts sensitive to the duration of depression symptoms. Attenuated will- such as “It probably won't be much fun,” or “I can't imagine I'll get ingness to expend effort for reward has also been observed among in- anything positive out of it.” Unfortunately, if the individual chooses not dividuals with subsyndromal depression (Yang et al., 2014). to start volunteering, they might miss out on opportunities to access Recently, the EEfRT task has been adapted for use in the fMRI en- other sources of reward that could come about as a result (e.g., positive vironment (Arulpragasam, Cooper, Nuutinen, & Treadway, 2018). In the interactions with new people, a sense of purpose). validation study for this task, the ventromedial prefrontal cortex was found Given research demonstrating that reward consumption may remain to be active during encoding of the expected subjective value for a trial, relatively intact among individuals with depression, it is possible that which involves the integration of information regarding the amount of the same individual may indeed enjoy volunteering if they choose to do possible reward and the amount of effort required to obtain it. This study so, regardless of their low anticipation of positive consequences. The did not examine associations between depression symptoms and ven- focus of BA treatments on increasing approach-oriented behavior, re- tromedial prefrontal cortex activity during expected subjective value en- gardless of internal barriers to action (e.g., hopelessness, low motiva- coding; however, given previous findings linking depression and atte- tion, low energy), may be particularly useful for patients presenting nuated willingness to expend effort for reward (Treadway et al., 2009, with low reward anticipation. Strategies used in BA treatments to in- Treadway et al., 2012; Yang et al., 2014), this task could be used in future crease approach-oriented behavior may promote engagement in situa- studies to investigate the influence of depression on expected subjective tions where patients are likely to experience in-vivo enjoyment, even value encoding. Though results are preliminary, the fMRI-adapted EEfRT though they do not anticipate that those situations will be pleasurable paradigm holds promise for identifying neural substrates of effort-based or meaningful. In other words, a BA therapist might take a “just do it” decision-making in depressed individuals. Future studies using this task approach and instruct the patient to engage in assigned activities even would also benefit from the assessment of neural activitvation in response if they do not feel motivated. Moreover, monitoring forms used to track to reward attainment, in addition to effort valuation and expected sub- activities and mood could be used to help the patient make connections jective value encoding.

6 C.N. Forbes Clinical Psychology Review 79 (2020) 101860

Results from these studies suggest that attenuated effort valuation is learning has primarily been assessed at the behavioral level of analysis associated with depression-relevant outcomes. Given that a primary using laboratory-based tasks. For example, the Probabilistic Reward goal of BA treatments is increasing patients' engagement in rewarding Task (PRT; Pizzagalli et al., 2005) provides participants with the op- activities, a patient's willingness to expend effort in pursuit of rewards portunity to obtain monetary reward for responding correctly on a is likely to play a critical role in homework compliance and motivation signal-detection task. The signal-detection task requires participants to for treatment. Specifically, the perception that engaging in a potentially identify the correct length (short or long) of a smile that was previously rewarding activity is “not worth the effort” would present an ante- presented on a drawing of a face. In order to elicit a response bias, cedent behavior to engaging in that behavior. Paradoxically, depres- correct identification of either the short or long smile is reinforced with sion-relevant symptoms such as low motivation, low energy, difficulties monetary reward three times more frequently than correct identifica- in concentration and decision-making, and hopelessness may be sig- tion of the other smile. Thus, response bias on the task is oper- nificant antecedent barriers to engaging in rewarding activities, even ationalized as the extent to which participants develop a systematic bias though these activities would likely result in mood improvement and a toward the stimulus that is reinforced more frequently over the course decrease in depression symptoms (Lejuez et al., 2001, 2011; Martell of the task. Performance on the task is thought to reflect the extent to et al., 2001). which decision-making behavior is influenced by reinforcement history. Strategies drawn from BA treatments may be particularly beneficial In one study using the PRT task (Vrieze et al., 2013) to assess reward for patients presenting with low effort valuation. As noted above, the learning in psychiatric inpatients with MDD and nonclinical controls, explicit focus of BA on modifying behavior regardless of undesired in- depressed participants demonstrated a lesser response bias toward the ternal experiences could be used to encourage patients to increase their stimulus that was more frequently reinforced over the course of the activity level, even while having thoughts that doing so would not be task, compared to control participants. Within the MDD group, in- worth the effort. Moreover, the identification of personal values that dividuals with low reward functioning demonstrated significiantly less one associates with living a meaningful life (i.e., values clarification) of a response bias over the course of the task, compared to depressed can be used to highlight the aspects of meaningful activities that may individuals with higher reward functioning. Moreover, individuals who make them feel “worth the effort.” Connecting specific behaviors to demonstrated poorer reward learning on the task were more likely to values (Lejuez et al., 2001, 2011) may provide an additional source of have a persisting MDD diagnosis after 8 weeks of pharmacological positive reinforcement for engaging in activities; in other words, a pa- treatment (OR = 7.84). These findings suggest that attenuated reward tient may experience a reinforcing sense of satisfaction while taking learning is associated with depression and low overall reward func- action consistent with their values. A focus on values may also assist tioning, and may hold promise as a predictor of response to anti- patients in making connections between present behaviors and desired depressant treatment. long-term consequences. Attenauted reward learning has also been observed among in- Breaking down behaviors into concrete, manageable steps may also dividuals with remitted depression. In two independent studies, adults be beneficial for patients with low effort valuation, because this would with remitted depression and nonclinical controls completed the PRT likely reduce the perceived amount of effort associated with a given (Pechtel, Dutra, Goetz, & Pizzagalli, 2013). Relative to nonclinical activity. This can be accomplished through strategies such as graded controls, individuals with remitted depression evidenced less of a re- task assignment (Martell et al., 2001) and the development of activity sponse bias toward more frequently rewarded stimuli over the course of heirarchies (Lejuez et al., 2001, 2011), which are used to gradually the task, suggesting that attenuation in reward learning may persist shape behavior toward desired goals and establish longer-term patterns beyond the remission of a depressive episode. A history of depression of behavior. For example, a patient in BA treatment might set a goal of predicted attenuated reward learning on the task over and above re- beginning a new exercise routine. Although the patient wants to in- sidual depression symptoms. While it is not possible to determine crease their exercise behavior, they may perceive that the potential whether attenuated reward learning reflects a trait-like characteristic, a benefits of exercising may not be worth the amount of effort involved in clinical feature of remitted depression, or a combination of both, given initiating the new routine. The patient and therapist might work to- that reward learing prior to the onset of a depressive eposide was not gether to identify personal values associated with physical exercise, assessed, the persistence of attenuated reward learning beyond the re- such as maintaining health and setting a good example for one's chil- mission of a depressive episode certainly merits further consideration. dren. This could provide an additional source of reinforcement for ex- The Iowa Gambling Task (IGT; Bechara, Damasio, Damasio, & ercise behavior (i.e., reinforcement associated with behaving in line Anderson, 1994) has also been used as a behavioral measure of reward with one's values). learning. During the IGT, participants are instructed to maximize profit Extending the example above, the patient and therapist could on a $2000 “loan” by selecting cards from four decks (decks A, B, C, and identify and schedule maneageable weekly goals related to exercise D). Two of the decks (A and B) yield larger rewards on individual trials behavior that do not require large amounts of effort expenditure. but also occasional large losses, resulting in a net loss over time, and are Weekly homework assignments might include purchasing exercise at- considered “disadvantageous.” Conversely, the other two decks (C and tire, researching local gyms, or taking a 10-min walk each day after D) yield smaller rewards on individual trials and smaller occasional work. Through shaping behavior in small increments, the patient and losses, resulting in a net gain over time, and are considered “advanta- therapist could gradually increase these behaviors until a regular ex- geous.” Reward learning on the task is operationalized as the extent to ercise routine is established. Furthermore, in the context of a positive which individuals are able to incorporate information about monetary and supportive therapeutic relationship, positive reinforcement pro- reward contingencies associated with each deck into future decisions vided by the therapist for completing weekly assignments may also about card selection, as reflected by a shift toward selection of cards facilitate continued engagement in those behaviors. from the advantageous decks over time (Must, Horvath, Nemeth, & Janka, 2013). 7.3. Alterations in reward learning Impaired reward learning on the IGT (i.e., a lesser shift toward selection of cards from the advantageous decks over time) has been as- Reward learning, or the ability to modulate behavior in response to sociated with depression-relevant outcomes. In several studies com- shifting environmental reward contingencies, may also provide insight paring IGT performance among depressed outpatients and nonclinical into mechanisms of change in BA treatments. Attenuated reward controls (Cella, Dymond, & Cooper, 2010; Moniz, Jesus, Gonçalves, learning is thought to contribute to abnormalities in reward-related Pacheco, & Viseu, 2016; Must et al., 2006), those with depression de- decision-making and goal-directed behavior among individuals with monstrated less of a shift toward “advantageous” decks over the course depression (Eshel & Roiser, 2010; Pizzagalli et al., 2005). Reward of the task. Cella et al. (2010) also found a significant relation between

7 C.N. Forbes Clinical Psychology Review 79 (2020) 101860 severity of depression symptoms and poorer reward learning on the demonstrated less activation in the ventral striatum and anterior cin- IGT. Moreover, a lesser tendency to adapt behavior in response to re- gulate cortex in response to positive social feedback during a “chat- inforcing contingencies has been observed among first-degree relatives room” task, compared to low-risk youth. Another study (McCabe, of suicide completers (Hoehne, Richard-Devantoy, Ding, Turecki, & Woffindale, Harmer, & Cowen, 2012) found that high-risk youth de- Jollant, 2015), and has been shown to distinguish depressed individuals monstrated less activation in the orbitofrontal cortex to the taste of with a recent (past 72 h) suicide attempt from nonclinical controls chocolate and pictures of chocolate (i.e., a physical reward), compared (Gorlyn, Keilp, Oquendo, Burke, & Mann, 2013). to low-risk youth. These results suggest that neural responsiveness to There is a focus in BA treatments on building sustainable patterns of both social and physical rewards may be impaired among youth at high behavior that facilitate regular engagement in rewarding activities. risk for depression; however, future research is needed to examine Impairment in the ability to adapt behavior in response to reinforcing whether neural responses differ across reward types in this population. contingencies may interfere with patients' ability to “learn” from posi- A small number of studies at the self-report level of analysis have tive reinforcement associated with past activities and incorporate this demonstrated differences in reward functioning across domains. Inone information into subsequent behavioral choices. For example, a patient study, social reward responsiveness on the Dimensional Anhedonia in BA treatment might choose to increase their engagement with so- Rating Scale (Rizvi et al., 2015) distinguished between depressed and cially rewarding activities by joining a local book club. During the first nondepressed individuals better than responsiveness to other reward book club meeting, the patient may experience a sense of enjoyment types (i.e., physical and recreational rewards). More recently, from positive interactions with new people. However, a patient with Khazanov, Ruscio, and Forbes (2019) developed the Positive Valence attenuated reward learning may have difficulty in using this positive Systems Scale (PVSS), whose factor-analytically derived subscales as- reinforcement as a guide for future behavior. The patient might ex- sess responsiveness to rewards in the domains of food, touch, the out- perience thoughts such as “I had a little bit of fun at the first meeting, doors, positive feedback, hobbies, social interactions, and goals. In the though I don't think I will enjoy the next one.” BA treatments often validation study for the PVSS, responsiveness to social rewards (and involve monitoring the impact of activities on mood (Lejuez et al., hobbies) significantly distinguished depressed individuals from non- 2001, 2011). This may assist patients in “learning” from positive re- clinical controls, consistent with other studies demonstrating large inforcement by highlighting associations between rewarding activities differences between depressed and nondepressed individuals inthe and positive mood changes. Over time, patients may be able to in- domain of social rewards (Olino et al., 2015; Rizvi et al., 2015). tegrate information about reward contingencies associated with activ- These findings are preliminary, and the relations between reward ities into the development of sustainable patterns of engagement with sub-types and depression require additional exploration within diverse environmental rewards. samples and across multiple levels of analysis. Nonetheless, results Reward learning may be particularly relevant to modifying beha- confirming that certain sub-types of reward are more relevant tode- vioral patterns of avoidance coping and increasing patients' use of al- pression than others may highlight the utility of emphasizing reward ternative coping strategies (i.e., TRAP and TRAC; Martell et al., 2001). types that are most relevant in BA treatments. For example, findings For example, a patient might want to replace the strategy of avoiding that low social reward functioning is a significant predictor of depres- time with their romantic partner in effort to prevent conflict with an sion severity, or that social rewards are significantly lower among de- approach-oriented strategy, such as discussing conflicts openly and pressed (vs. nondepressed) individuals, would suggest that BA treat- working collaboratively toward conflict resolution. The patient may ments should emphasize social engagement over and above other types experience a positive response from their partner as a result of utilizing of reward. approach-oriented strategies. However, a patient with attenuated re- Consideration of distinct sub-types of reward may also facilitate ward learning may have a difficult time incorporating these positive personalization of BA treatments to meet the needs of individual pa- consequences into decisions about conflicts that may occur in the fu- tients. For example, a patient who is employed as a surgeon may have ture. This may, in turn, result in a return to earlier avoidance strategies. many opportunities to experience positive reinforcement from mastery- As in the example of mood monitoring described above, the patient and oriented tasks, but may feel isolated as a result of having limited time therapist could work together to closely monitor the consequences of for hobbies and social relationships. For this patient, BA treatment approach-oriented strategies. This may assist the patient in drawing might focus on identifying feasible opportunities for recreation and connections between approach-oriented coping and positive con- social engagement within a busy schedule. The focus of BA treatment sequences, which could inform the patient's decisions to use approach- might be different, however, for a patient who is a full-time parent and oriented strategies in the future. enjoys fulfilling relationships with their partner and children, buthas few opportunities to engage in activities that generate feelings of ac- 7.4. Distinctions among reward types complishment. Given that this patient has sufficient social rewards, treatment could focus on identifying mastery-oriented activities such as A growing literature on differential associations between sub-types learning a new skill or taking on a leadership position in a local orga- of rewards and clinical outcomes may also inform the development and nization. Of course, emphasis on one or more sub-types of reward may refinement of BA treatments. Several broad categories of rewards have shift over the course of BA treatment in response to progress and been identified, including physical rewards, such as food, sex, and changes in patients' needs. physical touch; social rewards, such as positive social feedback and enjoyable social interactions; mastery-oriented rewards, such as 8. Additional considerations for future study meeting a goal or mastering a skill; and recreational rewards, such as spending time outdoors or participating in a hobby (Chapman, A number of hypotheses have been proposed regarding the ways in Chapman, & Raulin, 1976; Forbes & Dahl, 2012; Johnson, Fulford, & which BA treatments may address facets of (low) reward functioning Carver, 2012; Ryba & Hopko, 2012; Zhang, Harris, Split, Troiani, & that are characteristic of depression; particularly reward anticipation, Olson, 2016). For example, several fMRI studies have examined dif- effort valuation, reward learning, and responsiveness to specific sub- ferences in responding to physical and social rewards in youth at high types of rewards. The next step in testing these hypotheses would be to familial risk for depression. One study comparing youth with a family establish whether changes in reward functioning do indeed operate as a history of depression to those with no family history of mental illness mechanism of change in BA. Two novel treatments designed to speci- (Monk et al., 2008) found less nucleus accumbens activation in re- fically target low reward functioning may speak to this question: sponse to viewing happy faces among high-risk participants. Relatedly, Positive Affect Treatment (PAT; Craske et al., 2019) and BATA (Nagy Olino, Silk, Osterritter, and Forbes (2015) found that high-risk youth et al., 2020). Data on the efficacy of BATA is not currently available.

8 C.N. Forbes Clinical Psychology Review 79 (2020) 101860

However, promising preliminary data from a trial of PAT indicate that given that BA can leverage the heightened sensitivity to reward in this individuals receiving the treatment experienced significant increases in developmental period. Furthermore, interest in and motivation to positive affect, and decreases in depression symptoms, from pre-treat- pursue social rewards may be a particularly important target in BA ment to 6-month follow-up. Additional trials of these interventions may treatments for adolescents given the salience of these rewards for this shed light on whether improvements in reward functioning have a age group. Indeed, BA treatments have demonstrated efficacy in causal influence on symptom change. Moreover, larger-scale trials are treating depression among adolescents (Gaynor & Harris, 2008; Webb needed to examine whether BA treatments have a greater impact on et al., 2019; see Martin & Oliver, 2019, for a review). BA has been anhedonia and low positive emotionality relative to other depression identified as developmentally appropriate for adolescents, given that treatments, such as CBT and antidepressant medication. the treatment focuses primarily on behavioral change and does not In addition, given the diagnostic heterogeneity of depression require the full maturation of cognitive processes required for cognitive (Drysdale et al., 2017; Monroe & Anderson, 2015), future research on therapy (Dimidjian & McCauley, 2016). However, given that measures mechanisms of change in BA would benefit from examining the influ- of reward functioning designed for adults may have limited validity in ence of BA on reward functioning across different subsets of depressed adolescent populations (Olino, 2016), there is a need for further ex- participants. Recently, a precision medicine approach has been used to amination of BA processes using assessments that are sensitive to the predict which treatments for depression may be most efficacious for developmental context of adolescence. individual patients (Cohen & DeRubeis, 2018; Huibers et al., 2015). To Another promising direction for future research would be to identify this end, viewing BA treatments through the lens of compensatory versus and examine cognitive processes that may drive symptom change in BA capitalization models may facilitate increased understanding of which treatments. Rumination may be a particularly relevant mechanism, individuals and/or groups may benefit most from the intervention. The given that entanglement in ruminative thoughts may lead to isolation present review has conceptualized BA in terms of a compensatory and inactivity (e.g., an individual who spends a great deal of time at model, in which treatment strategies are designed to address deficits in home ruminating may be less likely to seek out opportunities to engage reward functioning. An implicit assumption of this model is that in- in meaningful and rewarding activities). Rumination may also interfere dividuals with greater deficits in reward functioning may benefit most with an individual's ability to connect with meaningful and rewarding from BA treatments. However, as noted previously, findings on the ef- aspects of activities, if they are more focused on ruminative thoughts ficacy of BA for individuals with severe depression have been mixed, than their experiences in the present moment. Indeed, decreases in with some studies demonstrating that BA is comparable to anti- rumination have been observed over the course of BA treatment. In a depressant treatment and more efficacious than CBT in this population study of internet-delivered exposure and BA for complicated grief and (Dimidjian et al., 2006) and others finding no significant differences in grief rumination, BA resulted in reductions in grief rumination at BA treatment response compared to CBT, antidepressant, or combined posttreatment (after 6–8 weeks) that were maintained at 3-months CBT-antidepressant treatment (Lorenzo-Luaces & Dobson, 2019) for (Eisma et al., 2015). Decreases in rumination over the course of BA severely depressed individuals. treatment have also been observed in a 16-week open trial of BA among An alternative approach would be a capitalization model, which individuals with atypical depression (Weinstock, Munroe, & Miller, emphasizes enhancing the strengths (vs. deficits) that individuals bring 2011), as well as in an 8-week group BA treatment for university stu- to treatment. A capitalization approach would imply that individuals dents with depression and anxiety (Zemestani, Davoudi, Mehrabizadeh, with higher pre-treatment reward functioning may benefit most from a & Zargar, 2014). Although decreases in rumination might be thought to treatment that leverages their pre-existing interest in and motivation to result from increases in control over cognitive processes, adjunctive pursue rewards. Consistent with this approach, a study of depressed cognitive control training along with standard BA treatment has not adults receiving a 16-week CBT treatment found better outcomes been associated with significant changes in treatment outcomes among individuals whose treatment was personalized to capitalize on (Moshier & Otto, 2017). An alternative explanation would be that in- their relative strengths, compared to those whose treatment was per- creased activity and behavioral engagement decrease rumination sonalized to address their relative deficits (Cheavens, Strunk, Lazarus, & simply by providing opportunities for activities that engage individuals' Goldstein, 2012). Future research would benefit from the application of cognitive processes. More research is needed, however, to understand this model in order to understand which individuals and groups may the relations between BA, rumination, and treatment outcomes. achieve the greatest responses to BA treatments (and, conversely, those The role of mindfulness (i.e., full attentional engagement with the who may be better-suited for other types of treatment). present moment), which can be conceptualized as an opponent process The efficacy of BA treatments for adolescents also warrants further to rumination, also warrants additional study. Martell et al.'s (2001) examination, particularly given that adolescence is a critical vulner- Behavioral Activation treatment and subsequent iterations of this ability period for the development of depression (Andersen & Teicher, treatment include mindfulness skills training, based upon the assump- 2008; Bertha & Balázs, 2013). As noted above, attenuated neural re- tion that increasing individuals' mindful engagement with enjoyable ward functioning has been observed among adolescents at familial risk and meaningful aspects of their experiences will increase the salience of for depression (Gotlib et al., 2010; McCabe et al., 2012; Monk et al., reinforcement (i.e., positive emotional responses) associated with as- 2008; Olino et al., 2014), as well as currently depressed adolescents signed activities. Given that mindfulness may oppose maladaptive (Stringaris et al., 2015). Though the PVS domain was developed based cognitive processes, such as worry and rumination, future research on on research on reward functioning in adults, there has been increasing BA treatments would benefit from investigating the relation of changes interest in developmental considerations related to PVS processes in mindfulness to treatment outcomes. (Olino, 2016). The influence of homework completion on BA treatment outcomes The PVS sub-domains of Initial Responsiveness and Effort Valuation also warrants consideration. Several preliminary studies (Collado et al., have been identified as particularly relevant to adolescence, asevi- 2014; Ryba et al., 2014; Santos et al., 2017) have found that greater denced by findings from self-report and behavioral studies that ap- engagement in assigned homework activities precedes or co-occurs with proach motivation and the pursuit of immediate (vs. delayed) rewards improvement in depression symptoms. And yet, motivational deficits is heightened during this developmental period (Anokhin, Golosheykin, associated with attenuated reward functioning may present a sig- & Mulligan, 2015; Cauffman et al., 2010; Lee et al., 2013). Respon- nificant antecedent barrier to homework completion. Indeed, lowmo- siveness to social rewards is also thought to be particularly relevant, tivation (Dimidjian & Hollon, 2011) and homework non-completion given the importance of affiliative processes in adolescent development (Hopko et al., 2011) have been identified as significant barriers to (Forbes, 2009). Viewed through the lens of a capitalization model, these treatment response. Balán, Lejuez, Hoffer, and Blanco (2016) en- results suggest that adolescents may be well-suited for BA treatments, couraged the integration of motivational interviewing strategies into

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Table 1 Domains of reward functioning corresponding to strategies in behavioral activation treatments.

Domain Behavioral activation treatment strategies

Reward anticipation Behavior-first approach; encourage patients to engage in activities even if they do not feel motivated or do not expect positive consequences. Increase accountability for engaging in activities (even in the absence of reward anticipation) by reviewing assigned homework in weekly sessions. Initial responsiveness Encourage patients to be mindful and present while engaging in rewarding activities in order to maximize the positive emotional consequences associated with those activities. Reward satiation Use monitoring forms to help patients identify activities that bring about sustained positive changes in mood. Reward learning Use monitoring forms to help patients learn to make connections between activities and positive mood changes that occur as a result. Encourage patients to incorporate information about positive consequences of past behavior into future behavioral choices. Reward probability Address feelings of hopelessness and low reward anticipation by discussing the probability that engaging in rewarding activities will bring about positive consequences. Delay Discuss short-term versus long-term consequences of behaviors (e.g., avoidance and withdrawal behaviors may bring about a short-term reduction in distress, while some adaptive reward-seeking behaviors may have longer-term positive consequences). Effort valuation Use values clarification to provide additional sources of reinforcement for effortful behaviors (i.e., reinforcement from taking action in linewithone's values). Use graded task assignment to break down effortful tasks into manageable sub-tasks. Reward subtypes Select activities from reward types that are most relevant to individual patients.

BA treatments in order to build motivation for homework completion; Understanding mechanisms of change in BA can facilitate the devel- for example, reminding patients of the personal relevance of activities, opment of more targeted and streamlined treatment approaches to best using functional analysis to address factors motivating noncompliance, meet the unique needs of individual patients. Although research on and collaborating with the patient to problem-solve barriers to home- biobehavioral mechanisms underlying reward functioning in depressed work completion. Additional strategies might include using graduated individuals has occurred in large part independently of research on BA activity assignment (i.e., starting with easier activities and working treatments for depression, integrating these disparate literatures will be toward more challenging ones over time), building activities into pa- an important next step for the development and refinement of BA tients' existing routines, and matching activities to relevant positive- treatments that efficiently target underlying biobehavioral processes in valence deficits. More research is needed to elucidate the influence of depression and other reward-related clinical problems. motivation on homework completion and BA treatment outcomes, as well as the development and refinement of strategies that can be used Role of funding sources by therapists to improve homework compliance among patients with low motivation. There were no funding sources for this study. Finally, as noted above, most experimental studies of reward functioning have used tasks that assess responding to monetary reward. Contributors While monetary reward tasks are certainly informative, findings from studies using these tasks may be limited in their generalizability to The author conceptualized the review paper, conducted literature other types of rewards. Given that individuals typically encounter a reviews, and wrote the manuscript. wide range of reward types in their daily lives, future research should utilize stimuli that maximize ecological validity by assessing in- Declaration of Competing Interest dividuals' responses to different types of rewards. For example, in addition to the social reward tasks described above, the IGT has recently The author has no conflicts of interests to declare. been adapted to assess responses to social, rather than monetary, rewards (Case & Olino, 2020). The development of similar behavioral Acknowledgements tasks to asses a variety of reward stimuli could provide insight into mechanisms of change that are associated with different types of re- The author would like to thank Dr. Matthew Tull, Dr. Kim Gratz, warding activities in the context of BA. and Dr. Jason Levine for their formative feedback on earlier versions of this manuscript.

9. Summary and conclusions References

Behavioral theories of depression (e.g., Ferster, 1973; Lewinsohn & Acierno, R., Gros, D. F., Ruggiero, K. J., Hernandez-Tejada, M. A., Knapp, R. G., Lejuez, C. Graf, 1973), which emphasize the influence of environmental reward W., ... Tuerk, P. W. (2016). Behavioral activation and therapeutic exposure for contingencies on the onset and maintenance of depression symptoms posttraumatic stress disorder: A noninferiority trial of treatment delivered in person and reated behaviors, form the theoretical basis for modern BA treat- versus home-based telehealth. Depression and Anxiety, 33(5), 415–423. https://doi. org/10.1002/da.22476. ments. Both Behavioral Activation (Martell et al., 2001) and Brief Be- Andersen, S. L., & Teicher, M. H. (2008). Stress, sensitive periods and maturational events havioral Activation Treatment for Depression (Lejuez et al., 2001, in adolescent depression. Trends in Neurosciences, 31(4), 183–191. https://doi.org/10. 2011) focus on increasing engagement with environmental sources of 1016/j.tins.2008.01.004. Anokhin, A. P., Golosheykin, S., & Mulligan, R. C. (2015). Long-term test–retest reliability positive reinforcement in order to bring about improvement in de- of delayed reward discounting in adolescents. In: Behavioural Processes, 111, 55–59. pression symptoms. Given that BA treatments focus specifically on in- https://doi.org/10.1016/j.beproc.2014.11.008. creasing engagement in rewarding activities, understanding the bio- Arias-Carrión, O., Stamelou, M., Murillo-Rodríguez, E., Menéndez-González, M., & Pöppel, E. (2010). Dopaminergic reward system: A short integrative review. behavioral processes underlying reward functioning may provide International Archives of Medicine, 3(1), 24. https://doi.org/10.1186/1755-7682-3-24. insight into mechanisms of change in BA. Specifically, findings related Arulpragasam, A. R., Cooper, J. A., Nuutinen, M. R., & Treadway, M. T. (2018). to neural and behavioral processes involved in sub-domains of reward Corticoinsular circuits encode subjective value expectation and violation for effortful goal-directed behavior. Proceedings of the National Academy of Sciences, 115(22), functioning, including reward anticipation, effort valuation, reward E5233–E5242. https://doi.org/10.1073/pnas.1800444115. learning, and responsiveness to sub-types of reward, can highlight Balán, I. C., Lejuez, C. W., Hoffer, M., & Blanco, C. (2016). Integrating motivational in- processes through which BA treatments may bring about improvement terviewing and brief behavioral activation therapy: Theoretical and practical considerations. Cognitive and Behavioral Practice, 23(2), 205–220. https://doi.org/10. in reward functioning and depression symptoms (see Table 1).

10 C.N. Forbes Clinical Psychology Review 79 (2020) 101860

1016/j.cbpra.2015.07.001. cognitive therapy for major depressive disorder: A secondary analysis of two ran- Bechara, A., Damasio, A. R., Damasio, H., & Anderson, S. W. (1994). Insensitivity to domized controlled trials. Clinical Psychological Science, 8(1), 36–51. https://doi.org/ future consequences following damage to human prefrontal cortex. Cognition, 10.1177/2167702619863427. 50(1–3), 7–15. https://doi.org/10.1016/0010-0277(94)90018-3. Eisma, M. C., Boelen, P. A., van den Bout, J., Stroebe, W., Schut, H. A., Lancee, J., & Beck, A. T., Rush, A. J., Shaw, B. F., & Emery, G. (1979). Cognitive therapy of depression. Stroebe, M. S. (2015). Internet-based exposure and behavioral activation for com- Guilford. plicated grief and rumination: A randomized controlled trial. Behavior Therapy, 46(6), Berridge, K. C., & Robinson, T. E. (2003). Parsing reward. Trends in Neurosciences, 26(9), 729–748. https://doi.org/10.1016/j.beth.2015.05.007. 507–513. https://doi.org/10.1016/S0166-2236(03)00233-9. Ekers, D., Richards, D., McMillan, D., Bland, J. M., & Gilbody, S. (2011). Behavioural Bertha, E. A., & Balázs, J. (2013). Subthreshold depression in adolescence: A systematic activation delivered by the non-specialist: Phase II randomised controlled trial. The review. European Child & Adolescent Psychiatry, 22(10), 589–603. https://doi.org/10. British Journal of Psychiatry, 198(1), 66–72. https://doi.org/10.1192/bjp.bp.110. 1007/s00787-013-0411-0. 079111. Brown, R. A., & Lewinsohn, P. M. (1984). A psychoeducational approach to the treatment Ekers, D., Webster, L., Van Straten, A., Cuijpers, P., Richards, D., & Gilbody, S. (2014). of depression: Comparison of group, individual, and minimal contact procedures. Behavioural activation for depression; an update of meta-analysis of effectiveness and Journal of Consulting and Clinical Psychology, 52(5), 774–783. https://doi.org/10. subgroup analysis. PLoS One, 9(6), e100100. https://doi.org/10.1371/journal.pone. 1037/0022-006X.52.5.774. 0100100. Case, J. A., & Olino, T. M. (2020). Approach and avoidance patterns in reward learning Ekers, D. M., Dawson, M. S., & Bailey, E. (2013). Dissemination of behavioural activation across domains: An initial examination of the Social Iowa Gambling Task. Behaviour for depression to mental health nurses: Training evaluation and benchmarked clinical Research and Therapy, 125, 103547. https://doi.org/10.1016/j.brat.2019.103547. outcomes. Journal of Psychiatric and Mental Health Nursing, 20(2), 186–192. https:// Cauffman, E., Shulman, E. P., Steinberg, L., Claus, E., Banich, M. T., Graham, S.,& doi.org/10.1111/j.1365-2850.2012.01906.x. Woolard, J. (2010). Age differences in affective decision making as indexed byper- Epstein, J., Pan, H., Kocsis, J. H., Yang, Y., Butler, T., Chusid, J., ... Silbersweig, D. A. formance on the Iowa Gambling Task. Developmental Psychology, 46(1), 193–207. (2006). Lack of ventral striatal response to positive stimuli in depressed versus https://doi.org/10.1037/a0016128. normal subjects. American Journal of Psychiatry, 163(10), 1784–1790. https://doi. Cella, M., Dymond, S., & Cooper, A. (2010). Impaired flexible decision-making in major org/10.1176/ajp.2006.163.10.1784. depressive disorder. Journal of Affective Disorders, 124(1–2), 207–210. https://doi. Eshel, N., & Roiser, J. P. (2010). Reward and punishment processing in depression. org/10.1016/j.jad.2009.11.013. Biological Psychiatry, 68(2), 118–124. https://doi.org/10.1016/j.biopsych.2010.01. Chapman, L. J., Chapman, J. P., & Raulin, M. L. (1976). Scales for physical and social 027. anhedonia. Journal of Abnormal Psychology, 85(4), 374–382. https://doi.org/10. Ferster, C. B. (1973). A functional analysis of depression. American Psychologist, 28(10), 1037/0021-843X.85.4.374. 857–870. https://doi.org/10.1037/h0035605. Cheavens, J. S., Strunk, D. R., Lazarus, S. A., & Goldstein, L. A. (2012). The compensation Ferster, C. B. (1974). “a functional analysis of depression”: Reply. American Psychologist, and capitalization models: A test of two approaches to individualizing the treatment 29(5), 361–362. https://doi.org/10.1037/h0038144. of depression. Behaviour Research and Therapy, 50(11), 699–706. https://doi.org/10. Ferster, C. B., & Skinner, B. F. (1957). Schedules of reinforcement. Appleton-Century-Crofts. 1016/j.brat.2012.08.002. Forbes, E. E. (2009). Where’s the fun in that? Broadening the focus on reward function in Chentsova-Dutton, Y., & Hanley, K. (2010). The effects of anhedonia and depression on depression. Biological Psychiatry, 66(3), 199. https://doi.org/10.1016/j.biopsych. hedonic responses. Psychiatry Research, 179(2), 176–180. https://doi.org/10.1016/j. 2009.05.001. psychres.2009.06.013. Forbes, E. E., & Dahl, R. E. (2012). Research review: Altered reward function in adoles- Chu, B. C., Crocco, S. T., Esseling, P., Areizaga, M. J., Lindner, A. M., & Skriner, L. C. cent depression: What, when and how? Journal of Child Psychology and Psychiatry, (2016). Transdiagnostic group behavioral activation and exposure therapy for youth 53(1), 3–15. https://doi.org/10.1111/j.1469-7610.2011.02477.x. anxiety and depression: Initial randomized controlled trial. Behaviour Research and Gard, D. E., Gard, M. G., Kring, A. M., & John, O. P. (2006). Anticipatory and con- Therapy, 76, 65–75. https://doi.org/10.1016/j.brat.2015.11.005. summatory components of the experience of pleasure: A scale development study. Cohen, Z. D., & DeRubeis, R. J. (2018). Treatment selection in depression. Annual Review Journal of Research in Personality, 40(6), 1086–1102. https://doi.org/10.1016/j.jrp. of Clinical Psychology, 14, 209–236. https://doi.org/10.1146/annurev-clinpsy- 2005.11.001. 050817-084746. Gard, D. E., Kring, A. M., Gard, M. G., Horan, W. P., & Green, M. F. (2007). Anhedonia in Collado, A., Castillo, S. D., Maero, F., Lejuez, C. W., & MacPherson, L. (2014). Pilot of the schizophrenia: Distinctions between anticipatory and consummatory pleasure. brief behavioral activation treatment for depression in Latinos with limited English Schizophrenia Research, 93(1–3), 253–260. https://doi.org/10.1016/j.schres.2007.03. proficiency: Preliminary evaluation of efficacy and acceptability. Behavior Therapy, 008. 45(1), 102–115. https://doi.org/10.1016/j.beth.2013.10.001. Gaynor, S. T., & Harris, A. (2008). Single-participant assessment of treatment mediators: Correa, M., Carlson, B. B., Wisniecki, A., & Salamone, J. D. (2002). Nucleus accumbens Strategy description and examples from a behavioral activation intervention for de- dopamine and work requirements on interval schedules. Behavioural Brain Research, pressed adolescents. Behavior Modification, 32(3), 372–402. https://doi.org/10.1177/ 137(1–2), 179–187. https://doi.org/10.1016/S0166-4328(02)00292-9. 0145445507309028. Craske, M. G., Meuret, A. E., Ritz, T., Treanor, M., Dour, H., & Rosenfield, D. (2019). Geaney, J. T., Treadway, M. T., & Smillie, L. D. (2015). Trait anticipatory pleasure pre- Positive affect treatment for depression and anxiety: A randomized clinical trial fora dicts effort expenditure for reward. PLoS One, 10(6), e0131357. https://doi.org/10. core feature of anhedonia. Journal of Consulting and Clinical Psychology, 87(5), 1371/journal.pone.0131357. 457–471. https://doi.org/10.1037/ccp0000396. Gorlyn, M., Keilp, J. G., Oquendo, M. A., Burke, A. K., & Mann, J. J. (2013). Iowa gam- Cuijpers, P., Van Straten, A., & Warmerdam, L. (2007). Behavioral activation treatments bling task performance in currently depressed suicide attempters. Psychiatry Research, of depression: A meta-analysis. Clinical Psychology Review, 27(3), 318–326. https:// 207(3), 150–157. https://doi.org/10.1016/j.psychres.2013.01.030. doi.org/10.1016/j.cpr.2006.11.001. Gortner, E. T., Gollan, J. K., Dobson, K. S., & Jacobson, N. S. (1998). Cognitive–behavioral Daughters, S. B., Braun, A. R., Sargeant, M. N., Reynolds, E. K., Hopko, D. R., Blanco, C., & treatment for depression: Relapse prevention. Journal of Consulting and Clinical Lejuez, C. W. (2008). Effectiveness of a brief behavioral treatment for inner-city illicit Psychology, 66(2), 377–384. https://doi.org/10.1037/0022-006X.66.2.377. drug users with elevated depressive symptoms: The life enhancement treatment for Gotlib, I. H., Hamilton, J. P., Cooney, R. E., Singh, M. K., Henry, M. L., & Joormann, J. substance use (LETS Act!). Journal of Clinical Psychiatry, 69(1), 122. http:// (2010). Neural processing of reward and loss in girls at risk for major depression. behavioralactivationtech.com/wp-content/uploads/2016/03/Daughters-et-al_2008. Archives of General Psychiatry, 67(4), 380–387. https://doi.org/10.1001/ pdf. archgenpsychiatry.2010.13. Dichter, G. S., Felder, J. N., Petty, C., Bizzell, J., Ernst, M., & Smoski, M. J. (2009). The Gray, J. A. (1972). The psychophysiological basis of introversion–extraversion: A mod- effects of psychotherapy on neural responses to rewards in major depression. ification of Eysenck’s theory. In V. D. Nebylitsyn, & J. A. Gray (Eds.). The biological Biological Psychiatry, 66(9), 886–897. https://doi.org/10.1016/j.biopsych.2009.06. bases of individual behavior (pp. 182–205). Academic Press. 021. Gray, J. A. (1990). Brain systems that mediate both emotion and cognition. Cognition & Dimidjian, S., Goodman, S. H., Sherwood, N. E., Simon, G. E., Ludman, E., Gallop, R., ... Emotion, 4(3), 269–288. https://doi.org/10.1080/02699939008410799. Beck, A. (2017). A pragmatic randomized clinical trial of behavioral activation for Hernstein, R. J. (1961). Relative and absolute strength of a response as a function of depressed pregnant women. Journal of Consulting and Clinical Psychology, 85(1), frequency of reinforcement. Journal of the Experimental Analysis of Behavior, 4(3), 26–36. https://doi.org/10.1037/ccp0000151. 267–272. https://doi.org/10.1901/jeab.1961.4-267. Dimidjian, S., & Hollon, S. D. (2011). What can be learned when empirically supported Hernstein, R. J. (1970). On the law of effect. Journal of the Experimental Analysis of treatments fail? Cognitive and Behavioral Practice, 18(3), 303–305. https://doi.org/10. Behavior, 13(2), 243–266. https://doi.org/10.1901/jeab.1961.4-267. 1016/j.cbpra.2011.02.001. Hershenberg, R., Smith, R. V., Goodson, J. T., & Thase, M. E. (2018). Activating veterans Dimidjian, S., Hollon, S. D., Dobson, K. S., Schmaling, K. B., Kohlenberg, R. J., Addis, M. toward sources of reward: A pilot report on development, feasibility, and clinical E., ... Jacobson, N. S. (2006). Randomized trial of behavioral activation, cognitive outcomes of a 12-week behavioral activation group treatment. Cognitive and therapy, and antidepressant medication in the acute treatment of adults with major Behavioral Practice, 25(1), 57–69. https://doi.org/10.1016/j.cbpra.2017.04.001. depression. Journal of Consulting and Clinical Psychology, 74(4), 658–670. https://doi. Ho, P. M., Cooper, A. J., Hall, P. J., & Smillie, L. D. (2015). Factor structure and construct org/10.1037/0022-006X.74.4.658. validity of the temporal experience of pleasure scales. Journal of Personality Dimidjian, S., & McCauley, E. (2016). Modular, scalable, and personalized: Priorities for Assessment, 97(2), 200–208. https://doi.org/10.1080/00223891.2014.940625. behavioral interventions for adolescent depression. Clinical Psychology: Science and Hoehne, A., Richard-Devantoy, S., Ding, Y., Turecki, G., & Jollant, F. (2015). First-degree Practice, 23(1), 58–61. https://doi.org/10.1111/cpsp.12142. relatives of suicide completers may have impaired decision-making but functional Drysdale, A. T., Grosenick, L., Downar, J., Dunlop, K., Mansouri, F., Meng, Y., ... Liston, C. cognitive control. Journal of Psychiatric Research, 68, 192–197. https://doi.org/10. (2017). Resting-state connectivity biomarkers define neurophysiological subtypes of 1016/j.jpsychires.2015.07.004. depression. Nature Medicine, 23(1), 28–38. https://doi.org/10.1038/nm.4246. Hopko, D. R., Lejuez, C. W., Lepage, J. P., Hopko, S. D., & McNeil, D. W. (2003). A brief Dunn, B. D., German, R. E., Khazanov, G., Xu, C., Hollon, S. D., & DeRubeis, R. J. (2019). behavioral activation treatment for depression: A randomized pilot trial within an Changes in positive and negative affect during pharmacological treatment and inpatient psychiatric hospital. Behavior Modification, 27(4), 458–469. https://doi.

11 C.N. Forbes Clinical Psychology Review 79 (2020) 101860

org/10.1177/0145445503255489. Martin, F., & Oliver, T. (2019). Behavioral activation for children and adolescents: A Hopko, D. R., Lejuez, C. W., Ruggiero, K. J., & Eifert, G. H. (2003). Contemporary be- systematic review of progress and promise. European Child & Adolescent Psychiatry, havioral activation treatments for depression: Procedures, principles, and progress. 28(4), 427–441. https://doi.org/10.1007/s00787-018-1126-z. Clinical Psychology Review, 23(5), 699–717. https://doi.org/10.1016/S0272- Mazzuchelli, T., Kane, R., & Rees, C. (2009). Behavioral activation treatments for de- 7358(03)00070-9. pression in adults: A meta-analysis and review. Clinical Psychology: Science and Hopko, D. R., Magidson, J. F., & Lejuez, C. W. (2011). Treatment failure in behavior Practice, 16(4), 383–411. https://doi.org/10.1007/s00787-018-1126-z. therapy: Focus on behavioral activation for depression. Journal of Clinical Psychology, McCabe, C., Woffindale, C., Harmer, C. J., & Cowen, P. J. (2012). Neural processing of 67(11), 1106–1116. https://doi.org/10.1002/jclp.20840. reward and punishment in young people at increased familial risk of depression. Hopko, D. R., Robertson, S. M., & Carvalho, J. P. (2009). Sudden gains in depressed Biological Psychiatry, 72(7), 588–594. https://doi.org/10.1016/j.biopsych.2012.04. cancer patients treated with behavioral activation therapy. Behavior Therapy, 40(4), 034. 346–356. https://doi.org/10.1016/j.beth.2008.09.001. McDowell, J. J. (1982). The importance of Hernstein’s mathematical statement of the law Huguet, A., Miller, A., Kisely, S., Rao, S., Saadat, N., & McGrath, P. J. (2018). A systematic of effect for behavior therapy. American Psychologist, 37(7), 771–779. https://doi. review and meta-analysis on the efficacy of Internet-delivered behavioral activation. org/10.1037/0003-066X.37.7.771. Journal of Affective Disorders, 235, 27–38. https://doi.org/10.1016/j.jad.2018.02. McFarland, B. R., & Klein, D. N. (2009). Emotional reactivity in depression: Diminished 073. responsiveness to anticipated reward but not to anticipated punishment or to non- Huibers, M. J., Cohen, Z. D., Lemmens, L. H., Arntz, A., Peeters, F. P., Cuijpers, P., & reward or avoidance. Depression and Anxiety, 26(2), 117–122. https://doi.org/10. DeRubeis, R. J. (2015). Predicting optimal outcomes in cognitive therapy or inter- 1002/da.20513. personal psychotherapy for depressed individuals using the personalized advantage McFarland, B. R., Shankman, S. A., Tenke, C. E., Bruder, G. E., & Klein, D. N. (2006). index approach. PLoS One, 10(11), e0140771. https://doi.org/10.1371/journal.pone. Behavioral activation system deficits predict the six-month course of depression. 0140771. Journal of Affective Disorders, 91(2–3), 229–234. https://doi.org/10.1016/j.jad.2006. Insel, T., Cuthbert, B., Garvey, M., Heinssen, R., Pine, D. S., Quinn, K., ... Wang, P. (2010). 01.012. Research domain criteria (RDoC): Toward a new classification framework for re- McMakin, D. L., Olino, T. M., Porta, G., Dietz, L. J., Emslie, G., Clarke, G., ... Brent, D. A. search on mental disorders. The American Journal of Psychiatry, 167(7), 748–751. (2012). Anhedonia predicts poorer recovery among youth with selective serotonin https://doi.org/10.1176/appi.ajp.2010.09091379. reuptake inhibitor treatment–resistant depression. Journal of the American Academy of Jacob, M. L., Keeley, M., Ritschel, L., & Craighead, W. E. (2013). Behavioural activation Child & Adolescent Psychiatry, 51(4), 404–411. https://doi.org/10.1016/j.jaac.2012. for the treatment of low-income, African American adolescents with major depressive 01.011. disorder: A case series. Clinical Psychology & Psychotherapy, 20(1), 87–96. https://doi. Moniz, M., Jesus, S., Gonçalves, E., Pacheco, A., & Viseu, J. (2016). Decision-making in org/10.1002/cpp.774. adult unipolar depressed patients and healthy subjects: Significant differences in net Jacobson, N. S. (1994). Contextualism is dead: Long live contextualism. Family Process, score and in non-traditional alternative measures. Neuropsychological Trends, 19, 33(1), 97–100. https://doi.org/10.1111/j.1545-5300.1994.00097.x. 7–15. https://doi.org/10.7358/neur-2016-019-moni. Jacobson, N. S., Dobson, K. S., Truax, P. A., Addis, M. E., Koerner, K., Gollan, J. K., ... Monk, C. S., Klein, R. G., Telzer, E. H., Schroth, E. A., Mannuzza, S., Moulton, J. L., ... Prince, S. E. (1996). A component analysis of cognitive-behavioral treatment for Blair, R. J. (2008). Amygdala and nucleus accumbens activation to emotional facial depression. Journal of Consulting and Clinical Psychology, 64(2), 295–304. https://doi. expressions in children and adolescents at risk for major depression. American Journal org/10.1037/0022-006X.64.2.295. of Psychiatry, 165(1), 90–98. https://doi.org/10.1176/appi.ajp.2007.06111917. Johnson, S. L., Fulford, D., & Carver, C. S. (2012). The double-edged sword of goal en- Monroe, S. M., & Anderson, S. F. (2015). Depression: The shroud of heterogeneity. Current gagement: Consequences of goal pursuit in bipolar disorder. Clinical Psychology & Directions in Psychological Science, 24(3), 227–231. https://doi.org/10.1177/ Psychotherapy, 19(4), 352–362. https://doi.org/10.1002/cpp.1801. 0963721414568342. Kanter, J. W., Santiago-Rivera, A. L., Santos, M. M., Nagy, G., López, M., Hurtado, G. D., & Morgan, J. K., Olino, T. M., McMakin, D. L., Ryan, N. D., & Forbes, E. E. (2013). Neural West, P. (2015). A randomized hybrid efficacy and effectiveness trial of behavioral response to reward as a predictor of increases in depressive symptoms in adolescence. activation for Latinos with depression. Behavior Therapy, 46(2), 177–192. https://doi. Neurobiology of Disease, 52, 66–74. https://doi.org/10.1016/j.nbd.2012.03.039. org/10.1016/j.beth.2014.09.011. Moshier, S. J., & Otto, M. W. (2017). Behavioral activation treatment for major depres- Kasch, K. L., Rottenberg, J., Arnow, B. A., & Gotlib, I. H. (2002). Behavioral activation and sion: A randomized trial of the efficacy of augmentation with cognitive control inhibition systems and the severity and course of depression. Journal of Abnormal training. Journal of Affective Disorders, 210, 265–268. https://doi.org/10.1016/j.jad. Psychology, 111(4), 589–597. https://doi.org/10.1037/0021-843X.111.4.589. 2017.01.003. Kazdin, A. E. (2005). Treatment outcomes, common factors, and continued neglect of Must, A., Horvath, S., Nemeth, V. L., & Janka, Z. (2013). The Iowa Gambling Task in mechanisms of change. Clinical Psychology: Science and Practice, 12(2), 184–188. depression–what have we learned about sub-optimal decision-making strategies? https://doi.org/10.1093/clipsy.bpi023. Frontiers in Psychology, 4, 732. https://doi.org/10.3389/fpsyg.2013.00732. Keren, H., O’Callaghan, G., Vidal-Ribas, P., Buzzell, G. A., Brotman, M. A., Leibenluft, E., Must, A., Szabó, Z., Bódi, N., Szász, A., Janka, Z., & Kéri, S. (2006). Sensitivity to reward ... Stringaris, A. (2018). Reward processing in depression: A conceptual and meta- and punishment and the prefrontal cortex in major depression. Journal of Affective analytic review across fMRI and EEG studies. American Journal of Psychiatry, 175(11), Disorders, 90(2–3), 209–215. https://doi.org/10.1016/j.jad.2005.12.005. 1111–1120. https://doi.org/10.1176/appi.ajp.2018.17101124. Nagy, G. A., Cernasov, P., Pisoni, A., Walsh, E., Dichter, G. S., & Smoski, M. J. (2020). Khazanov, G. K., & Ruscio, A. M. (2016). Is low positive emotionality a specific risk factor Reward network modulation as a mechanism of change in behavioral activation. for depression? A meta-analysis of longitudinal studies. Psychological Bulletin, 142(9), Behavior Modification, 44(2), 186–213. https://doi.org/10.1177/ 991–1015. https://doi.org/10.1037/bul0000059. 0145445518805682. Khazanov, G. K., Ruscio, A. M., & Forbes, C. N. (2019). The positive valence systems scale: National Institute of Mental Health (2018). RDoC changes of the matrix (CMAT) update: Development and validation. Assessment, 1073191119869836. https://doi.org/10. Proposed positive valence domain revisions. https://www.nimh.nih.gov/about/ 1177/1073191119869836. advisory-boards-and-groups/namhc/reports/cmat-pvs-report-508_157003.pdf. Klein, D. (1984). Depression and anhedonia. In D. C. Clark, & J. Fawcett (Eds.). Anhedonia Nestler, E. J., & Carlezon, W. A. (2006). The mesolimbic dopamine reward circuit in and affect deficit states (pp. 1–14). PMA Publishing Corporation. depression. Biological Psychiatry, 59(12), 1151–1159. https://doi.org/10.1016/j. Knutson, B., Adams, C. M., Fong, G. W., & Hommer, D. (2001). Anticipation of increasing biopsych.2005.09.018. monetary reward selectively recruits nucleus accumbens. Journal of Neuroscience, Nusslock, R., & Alloy, L. B. (2017). Reward processing and mood-related symptoms: An 21(16), RC159. https://doi.org/10.1523/JNEUROSCI.21-16-j0002.2001. RDoC and translational neuroscience perspective. Journal of Affective Disorders, 216, Lee, N. C., De Groot, R. H. M., Boschloo, A., Dekker, S., Krabbendam, L., & Jolles, J. 3–16. https://doi.org/10.1016/j.jad.2017.02.001. (2013). Age and educational track influence adolescent discounting of delayed re- Olino, T. M. (2016). Future research directions in the positive valence systems: wards. Frontiers in Psychology, 4, 993. https://doi.org/10.3389/fpsyg.2013.00993. Measurement, development, and implications for youth unipolar depression. Journal Lejuez, C. W., Hopko, D. R., Acierno, R., Daughters, S. B., & Pagoto, S. L. (2011). Ten-year of Clinical Child & Adolescent Psychology, 45(5), 681–705. https://doi.org/10.1080/ revision of the brief behavioral activation treatment for depression: Revised treat- 15374416.2015.1118694. ment manual. Behavior Modification, 35(2), 111–161. https://doi.org/10.1177/ Olino, T. M., McMakin, D. L., & Forbes, E. E. (2018). Toward an empirical multi- 0145445510390929. dimensional structure of anhedonia, reward sensitivity, and positive emotionality: An Lejuez, C. W., Hopko, D. R., & Hopko, S. D. (2001). A brief behavioral activation treat- exploratory factor analytic study. Assessment, 25(6), 679–690. https://doi.org/10. ment for depression: Treatment manual. Behavior Modification, 25(2), 255–286. 1177/1073191116680291. https://doi.org/10.1177/0145445501252005. Olino, T. M., McMakin, D. L., Morgan, J. K., Silk, J. S., Birmaher, B., Axelson, D. A., ... Lewinsohn, P. M., & Graf, M. (1973). Pleasant activities and depression. Journal of Forbes, E. E. (2014). Reduced reward anticipation in youth at high-risk for unipolar Consulting and Clinical Psychology, 41(2), 261–268. https://doi.org/10.1037/ depression: A preliminary study. Developmental Cognitive Neuroscience, 8, 55–64. h0035142. https://doi.org/10.1016/j.dcn.2013.11.005. Lewinsohn, P. M., Sullivan, J. M., & Grosscup, S. J. (1980). Changing reinforcing events: Olino, T. M., Silk, J. S., Osterritter, C., & Forbes, E. E. (2015). Social reward in youth at An approach to the treatment of depression. Psychotherapy: Theory, Research & risk for depression: A preliminary investigation of subjective and neural differences. Practice, 17(3), 322–334. https://doi.org/10.1037/h0085929. Journal of Child and Adolescent Psychopharmacology, 25(9), 711–721. https://doi.org/ Lorenzo-Luaces, L., & Dobson, K. S. (2019). Is Behavioral Activation (BA) more effective 10.1089/cap.2014.0165. than Cognitive Therapy (CT) in severe depression? A reanalysis of a landmark trial. Pechtel, P., Dutra, S. J., Goetz, E. L., & Pizzagalli, D. A. (2013). Blunted reward respon- International Journal of Cognitive Therapy, 12(2), 73–82. https://doi.org/10.1007/ siveness in remitted depression. Journal of Psychiatric Research, 47(12), 1864–1869. s41811-019-00044-8. https://doi.org/10.1016/j.jpsychires.2013.08.011. MacPhillamy, D. J., & Lewinsohn, P. M. (1971). Pleasant events schedule. University of Phillips, M. L., Drevets, W. C., Rauch, S. L., & Lane, R. (2003a). Neurobiology of emotion Oregon. perception I: The neural basis of normal emotion perception. Biological Psychiatry, Martell, C. R., Addis, M. E., & Jacobson, N. S. (2001). Depression in context: Strategies for 54(5), 504–514. https://doi.org/10.1016/S0006-3223(03)00168-9. guided action. W.W. Norton & Company. Phillips, M. L., Drevets, W. C., Rauch, S. L., & Lane, R. (2003b). Neurobiology of emotion

12 C.N. Forbes Clinical Psychology Review 79 (2020) 101860

perception II: Implications for major psychiatric disorders. Biological Psychiatry, 1037/a0028813. 54(5), 515–528. https://doi.org/10.1016/S0006-3223(03)00171-9. Treadway, M. T., Buckholtz, J. W., Schwartzman, A. N., Lambert, W. E., & Zald, D. H. Pizzagalli, D. A., Holmes, A. J., Dillon, D. G., Goetz, E. L., Birk, J. L., Bogdan, R., ... Fava, (2009). Worth the “EEfRT”? The effort expenditure for rewards task as an objective M. (2009). Reduced caudate and nucleus accumbens response to rewards in un- measure of motivation and anhedonia. PLoS One, 4(8), e6598. https://doi.org/10. medicated individuals with major depressive disorder. American Journal of Psychiatry, 1371/journal.pone.0006598. 166(6), 702–710. https://doi.org/10.1176/appi.ajp.2008.08081201. Treadway, M. T., & Zald, D. H. (2011). Reconsidering anhedonia in depression: Lessons Pizzagalli, D. A., Jahn, A. L., & O’Shea, J. P. (2005). Toward an objective characterization from translational neuroscience. Neuroscience & Biobehavioral Reviews, 35(3), of an anhedonic phenotype: A signal-detection approach. Biological Psychiatry, 57(4), 537–555. https://doi.org/10.1016/j.neubiorev.2010.06.006. 319–327. https://doi.org/10.1016/j.biopsych.2004.11.026. Tull, M. T., Berghoff, C. R., Bardeen, J. R., Schoenleber, M., & Konkle-Parker, D. J.(2018). PVS Proceedings (2011). NIMH research domain criteria (RDoC) positive valence systems An initial open trial of a brief behavioral activation treatment for depression and domain workshop, Rockville, Maryland. https://www.nimh.nih.gov/research/ medication adherence in HIV-infected patients. Behavior Modification, 42(2), research-funded-by-nimh/rdoc/positive-valence-systems-workshop-proceedings. 196–209. https://doi.org/10.1177/0145445517723901. shtml. Uher, R., Perlis, R. H., Henigsberg, N., Zobel, A., Rietschel, M., Mors, O., ... McGuffin, P. Rizvi, S. J., Quilty, L. C., Sproule, B. A., Cyriac, A., Bagby, R. M., & Kennedy, S. H. (2015). (2012). Depression symptom dimensions as predictors of antidepressant treatment Development and validation of the Dimensional Anhedonia Rating Scale (DARS) in a outcome: Replicable evidence for interest-activity symptoms. Psychological Medicine, community sample and individuals with major depression. Psychiatry Research, 42(5), 967–980. https://doi.org/10.1017/S0033291711001905. 229(1–2), 109–119. https://doi.org/10.1016/j.psychres.2015.07.062. Vrieze, E., Pizzagalli, D. A., Demyttenaere, K., Hompes, T., Sienaert, P., de Boer, P., ... Ryba, M. M., & Hopko, D. R. (2012). Gender differences in depression: Assessing med- Claes, S. (2013). Reduced reward learning predicts outcome in major depressive iational effects of overt behaviors and environmental reward through daily diary disorder. Biological Psychiatry, 73(7), 639–645. https://doi.org/10.1016/j.biopsych. monitoring. Depression Research and Treatment, 2012, 865679. https://doi.org/10. 2012.10.014. 1155/2012/865679. Wagner, A. W., Jakupcak, M., Kowalski, H. M., Bittinger, J. N., & Golshan, S. (2019). Ryba, M. M., Lejuez, C. W., & Hopko, D. R. (2014). Behavioral activation for depressed Behavioral activation as a treatment for posttraumatic stress disorder among re- breast cancer patients: The impact of therapeutic compliance and quantity of activ- turning veterans: A randomized trial. Psychiatric Services, 70(10), 867–873. https:// ities completed on symptom reduction. Journal of Consulting and Clinical Psychology, doi.org/10.1176/appi.ps.201800572. 82(2), 325–335. https://doi.org/10.1037/a0035363. Webb, C. A., Stanton, C. H., Bondy, E., Singleton, P., Pizzagalli, D. A., & Auerbach, R. P. Salamone, J. D., Correa, M., Farrar, A., & Mingote, S. M. (2007). Effort-related functions (2019). Cognitive versus behavioral skills in CBT for depressed adolescents: of nucleus accumbens dopamine and associated forebrain circuits. Disaggregating within-patient versus between-patient effects on symptom change. Psychopharmacology, 191(3), 461–482. https://doi.org/10.1007/s00213-006-0668-9. Journal of Consulting and Clinical Psychology, 87(5), 484–490. https://doi.org/10. Santos, M. M., Rae, J. R., Nagy, G. A., Manbeck, K. E., Hurtado, G. D., West, P., ... Kanter, 1037/ccp0000393. J. W. (2017). A patient-level session-by-session evaluation of behavioral activation’s Weinstock, L. M., Munroe, M. K., & Miller, I. W. (2011). Behavioral activation for the mechanism of action. Journal of Behavior Therapy and Experimental Psychiatry, 54, treatment of atypical depression: A pilot open trial. Behavior Modification, 35(4), 93–100. https://doi.org/10.1016/j.jbtep.2016.07.003. 403–424. https://doi.org/10.1177/0145445511405646. Sherdell, L., Waugh, C. E., & Gotlib, I. H. (2012). Anticipatory pleasure predicts moti- Whitton, A. E., Treadway, M. T., & Pizzagalli, D. A. (2015). Reward processing dys- vation for reward in major depression. Journal of Abnormal Psychology, 121(1), function in major depression, bipolar disorder and schizophrenia. Current Opinion in 51–60. https://doi.org/10.1037/a0024945. Psychiatry, 28(1), 7–12. https://doi.org/10.1097/yco.0000000000000122. Skinner, B. F. (1953). Some contributions of an experimental analysis of behavior to Yang, X. H., Huang, J., Zhu, C. Y., Wang, Y. F., Cheung, E. F., Chan, R. C., & Xie, G. R. psychology as a whole. American Psychologist, 8(2), 69–78. https://doi.org/10.1037/ (2014). Motivational deficits in effort-based decision making in individuals with h0054118. subsyndromal depression, first-episode and remitted depression patients. Psychiatry Skinner, B. F. (1957). The experimental analysis of behavior. American Scientist, 45(4), Research, 220(3), 874–882. https://doi.org/10.1016/j.psychres.2014.08.056. 343–371. https://www.jstor.org/stable/27826953. Zemestani, M., Davoudi, I., Mehrabizadeh, H. M., & Zargar, Y. (2014). Effectiveness of Smoski, M. J., Felder, J., Bizzell, J., Green, S. R., Ernst, M., Lynch, T. R., & Dichter, G. S. group behavioral activation on depression, anxiety and rumination in patients with (2009). fMRI of alterations in reward selection, anticipation, and feedback in major depression and anxiety. Journal of Clinical Psychology, 5(4), 73–84 doi unavailable. depressive disorder. Journal of Affective Disorders, 118(1–3), 69–78. https://doi.org/ Zhang, H., Harris, L., Split, M., Troiani, V., & Olson, I. R. (2016). Subclinical anhedonia 10.1016/j.jad.2009.01.034. and individual differences in orbitofrontal cortex sulcogyral morphology. Human Stringaris, A., Vidal-Ribas Belil, P., Artiges, E., Lemaitre, H., Gollier-Briant, F., Wolke, S., Brain Mapping, 37(11), 3811–3873. https://doi.org/10.1002/hbm.23282. ... Paillère-Martinot, M.-L. (2015). The brain’s response to reward anticipation and depression in adolescence: Dimensionality, specificity, and longitudinal predictions Courtney N. Forbes is a doctoral candidate in clinical psychology at the University of in a community-based sample. American Journal of Psychiatry, 172(12), 1215–1223. Toledo. Her research interests include transdiagnostic biobehavioral processes in mood, https://doi.org/10.1176/appi.ajp.2015.14101298. anxiety, and trauma-related disorders, as well as integration of findings from basic re- Treadway, M. T., Bossaller, N. A., Shelton, R. C., & Zald, D. H. (2012). Effort-based de- search into the development and dissemination of evidence-based treatments. cision-making in major depressive disorder: A translational model of motivational anhedonia. Journal of Abnormal Psychology, 121(3), 553–558. https://doi.org/10.