Rethinking the Role of Thought Suppression in Psychological Models and Treatment

The Journal of Neuroscience, November 22, 2017 • 37(47):11293–11295 • 11293

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X Caitlin S.M. Cowan,1 Shiu F. Wong,2 and Lillian Le2 1APC Microbiome Institute, University College Cork, Cork T12 YT20, Ireland, and 2School of Psychology, University of New South Wales, Sydney, 2052 New South Wales, Australia Review of Gagnepain et al.

Wouldn’t it be nice to forget our deepest to controlling the intrusion per se. In a driven by a frontoparietal network, in- fears and cast aside our regrets? Unfortu- recent article in The Journal of Neurosci- cluding the dlPFC and other frontal nately, for many individuals, it is precisely ence, Gagnepain et al. (2017) sought to regions. Furthermore, this inhibitory these unpleasant details that always seem determine whether the cognitive and af- frontoparietal network downregulated to resurface. The repeated, distressing intru- fective components of thought suppres- both hippocampal and amygdalar activity sion of unwanted thoughts and memories is a sion are achieved through similar or in a manner suggesting parallel regulation common feature of many psychological distinct neural networks. of memories and associated emotional re- disorders (Wenzlaff and Wegner, 2000). In that study, functional connectivity sponses. The authors also observed indi- Controlling or suppressing such intrusive during a thought suppression task was as- vidual differences in suppression ability thoughts is a demanding cognitive process sessed in healthy young adults (N ϭ 24) that correlated with engagement of this that typically involves top-down inhibition using fMRI. First, participants learned as- neural “suppression network.” That is, of the hippocampus, a region known for its sociations between images of faces paired effective suppressors, who reported low role in memory regulation, by prefrontal with neutral or aversive scenes. Next, in rates of intrusions, exhibited stronger “control” regions (particularly the right the scanner, participants were shown the coupling in the suppression network dur- dorsolateral prefrontal cortex [dlPFC]) face-cues at random. On half the trials, ing the task (i.e., higher inverse correla- (Anderson et al., 2016). However, not all they were instructed to consciously recall tion between activity in the frontoparietal intrusions are equal. Psychologically dis- the paired scene in detail; on the remain- regions and activity in the hippocampus tressing intrusions have an added affective ing trials, they were instructed to engage and amygdala). These individuals also ex- component, meaning that their suppres- in thought suppression by blocking hibited greater levels of affect suppression sion requires individuals to regulate their thoughts of the paired scene and instead (i.e., diminished negative affect for sup- negative emotional response in addition blanking their mind while fixating on the pressed aversive scenes in the test phase). face cue. Throughout the task, partici- In contrast, ineffective suppressors re- pants reported whether the paired scene ported frequent intrusions during sup- Received Sept. 1, 2017; revised Oct. 10, 2017; accepted Oct. 13, 2017. came to mind during the trial. Finally, pression trials, exhibited weaker coupling This work was supported through the Joint Programming Initiative - A Healthy Diet for Healthy Life (JPI-HDHL) project HEALTHMARK by Science participants underwent an associative rec- between regions in the suppression net- Foundation Ireland (SFI) 16/ERA-HDHL/3362. The APC Microbiome Insti- ognition test and rated the emotional va- work, and rated aversive scenes as more tute was supported by SFI through the Irish Government’s National Devel- lence of each of the original scenes. negative after (attempted) suppression. opment Plan Grant 12/RC/2273. L.L. was supported by an Australian Using dynamic causal modeling and Based on these findings, the authors Government Research Training Program Scholarship. We thank Ryan Car- celler for assistance with the figure. Bayesian model selection, Gagnepain et al. proposed that individual differences in The authors declare no competing financial interests. (2017) identified the direction of com- thought suppression may reflect vulnera- Correspondence should be addressed to Dr. Caitlin S. M. Cowan, Labo- munication between a network of brain bility to psychopathology and that train- ratory of Neurogastroenterology, APC Microbiome Institute, Room 5.35, regions that were differentially activated ing in effective thought suppression may Biosciences Building, University College Cork, Cork, T12 YT20, Ireland. E-mail: [email protected]. during thought suppression. The final enhance psychological treatment out- DOI:10.1523/JNEUROSCI.2511-17.2017 model supported the hypothesis that sup- comes. This proposal, although appeal- Copyright © 2017 the authors 0270-6474/17/3711293-03$15.00/0 pression involves a top-down process ing, first needs to be considered in the 11294 • J. Neurosci., November 22, 2017 • 37(47):11293–11295 Cowan et al. • Journal Club context of established psychological models that have long characterized thought suppression as a key maintaining factor across a range of disorders, notably obsessive-compulsive disorder (OCD) and posttraumatic stress disorder (PTSD). OCD is characterized by the presence of recurrent and persistent intrusive thoughts, images, or impulses that cause marked anxiety and distress (American Psychiatric Association, 2013). Similarly, intrusive thoughts about an experienced trauma are a hallmark symptom of PTSD that causes significant psychological distress (American Psychiatric Association, 2013). Cognitive-behavioral models suggest that this distress arises due to negative interpretations of intrusive thoughts as personally significant and dangerous (Fig. 1). For example, an individual with OCD may believe that having an intrusive thought (e.g., “I’m going to kill someone”) increases the likelihood of the action occur- ring, making the individual personally responsible for their thoughts and causing guilt and anxiety (Salkovskis, 1985). In Figure1. Acognitive-behavioralmodelofthoughtsuppressionasamaintainingfactorinpsychopathology.Itisproposedthat PTSD, intrusive memories of the trauma intrusive thoughts and memories evoke negative emotional responses (sadness, anxiety, fear) due to negative appraisals or often induce fear if the intrusion is inter- interpretations of the meaning of the intrusions. The use of thought suppression to regulate negative emotions may bring some initial, short-lasting relief but often has detrimental long-term effects. These include a paradoxical increase in the frequency of preted as a signal that the individual is intrusive thoughts (rebound effects) and strengthening of negative appraisals when thought suppression fails (ineffective con- under current threat (Ehlers and Clark, trol).TheresultsofGagnepainetal.(2017)suggestthatweakconnectivitybetweenthePFCandmedialtemporallobestructures 2000). (hippocampus [HPC]; amygdala [AMYG]) may contribute to ineffective control and individual differences in vulnerability to this It should be unsurprising that individ- negative cycle of suppression. uals who experience intrusive thoughts as highly distressing may attempt to sup- press these thoughts as a strategy to regu- The findings of Gagnepain et al. (2017) 2017). Unfortunately, most of these clini- late their negative emotional response. suggest that some individuals, even in cal imaging studies have examined neuro- Unfortunately, it seems that thought sup- healthy populations, may be more vulner- biological differences only after diagnosis, pression can lead to paradoxical increases able to the negative cycle depicted in Fig- making it difficult to determine direction- in the frequency of intrusions and the in- ure 1 due to underlying neurobiological ality of effects. The findings of Gagnepain tensity of associated distress, a phenome- differences that make them more likely to et al. (2017) suggest that more research is non known as the rebound effect that is fail at thought suppression. There is some warranted to specifically examine func- observed across a variety of clinical condi- limited support for this hypothesis in the tional connectivity during thought sup- tions (e.g., Purdon et al., 2005; Nickerson clinical literature. One study found that pression across different psychological et al., 2016). In addition to the negative depressed women exhibit attenuated dlPFC disorders, particularly prospective studies to cycle created by rebound effects, failed activation during thought suppression determine whether functional abnormali- attempts at thought suppression (i.e., in- compared with healthy women (Carew et ties precede and predict symptom onset. effective control) can also exacerbate al., 2013). Importantly, women at risk for Another critical consideration for fu- psychological symptoms by reinforcing depression (first-degree relative with de- ture research will be to establish the spec- negative interpretations of intrusions. pression) showed an intermediate dlPFC ificity of the present findings to thought Specifically, individuals fail to learn that response, supporting the assertion that suppression. The suppression network intrusions are nonthreatening, preventing neurobiological differences signal risk overlaps with networks underlying other extinction of negative beliefs. In PTSD, rather than simply being consequences of emotion regulation strategies, such as suppression of trauma-related intrusions the disorder. Although brain-imaging cognitive reappraisal, a key component of can further prevent elaborate processing studies in OCD populations have pro- cognitive-behavioral therapies used to of the trauma into memory, thus main- duced inconsistent results (Menzies et al., break the suppression cycle by addressing taining psychological symptoms (Foa and 2008), there is some evidence for struc- negative interpretations of thoughts (Blechert Kozak, 1986). Supporting this model, tural and functional changes in the sup- et al., 2015). Reappraisal also increases frontal thought suppression is more frequent in pression network in PTSD, including activation (including in the dlPFC) and de- clinical populations (Magee et al., 2012) reduced volume of the hippocampus and creases amygdala activation (Buhle et al., and high thought suppression is predic- anterior cingulate cortex, hyperactivity of 2014). In a direct comparison of suppres- tive of increased symptom severity at later the amygdala response to stress, and re- sion and reappraisal, both strategies acti- time points (e.g., Mayou et al., 2002; duced prefrontal-amygdala connectivity vated the same prefrontal regions, but this Wenzlaff and Luxton, 2003). (O’Doherty et al., 2015; Clausen et al., response was faster during reappraisal and Cowan et al. • Journal Club J. Neurosci., November 22, 2017 • 37(47):11293–11295 • 11295 only reappraisal inhibited amygdala re- In conclusion, Gagnepain et al. 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