Journal of Affective Disorders 260 (2020) 728–737 Contents lists available at ScienceDirect Journal of Affective Disorders journal homepage: www.elsevier.com/locate/jad Review article Acceptance and Commitment Therapy (ACT) to reduce depression: A T systematic review and meta-analysis ⁎ Bai Zhengganga, , Luo Shigaa, Zhang Luyaoa, Wu Sijiea, Chi Irisb a Evidence-Based Research Center of Social Science & Health, Public Affair School of Nanjing University of Science & Technology, Nanjing 210000, China b Suzanne Dworak-Peck School of Social Work, University of Southern California, Los Angeles, USA ARTICLE INFO ABSTRACT Keywords: Objectives: The aim of this study is to investigate the effectiveness of ACT on depression reduction and further Acceptance and Commitment Therapy examine the relationship between different follow-up periods, different degree of depression, and different ageof Systematic review patients through subgroup analysis. Meta-analysis Methods: Relevant electronic databases were searched from Jan 2010 to Aug 2018, including CNKI, WANFANG, Depression PubMed, EMBASE, Cochrane Library, PsycINFO. Two reviewers independently screened for eligible studies, ex- tracted data, and assessed risk of bias of the included studies. The Cochrane Collaboration's bias assessment tool was used to evaluate the risk of bias for included studies, and Review Manager 5.3 Software for the meta-analysis Results: 18 studies with 1,088 participants were included in the review. Four studies were rated as high-quality studies, and the remaining 14 studies were rated as moderate quality studies. ACT significantly reduced de- pression as compared with the control group [SMD = 0.59, 95% CI (0.38, 0.81)]. The subgroup analysis found a significant difference between ACT and control group after post-intervention, three months follow up,mild depression group and adults group, [SMD= 0.62, 95% CI (0.35, 0.90), [SMD= 0.55, 95% CI (0.23, 0.87)], [SMD= 0.65, 95% CI (0.40, 0.91)], [SMD= 0.52, 95% CI (0.33, 0.71)] respectively. Limitations: The heterogeneity between included studies results in heterogeneity of the results. Most of the specific methods for random sequence generation and allocation concealment were not clear. The search results had limitations since only the published studies in Chinese and English were searched and lacked a search for gray and paper documents. Conclusions: The current study suggested that ACT was significantly for reducing depressive symptoms compared with the control group, especially at three months of follow-up, adult group and mild depression. More research is needed to investigate the difference effects for minor group, moderate and severe depression and long-term follow-up. 1. Introduction taken in tablet form. There are several different types of antidepressants, and the most widely prescribed types are selective serotonin reuptake At the global level, approximately 322 million people, which is 4.4% inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors of the world's population, are suffering from depression (World Health (SNRIs). (The National Health Service, 2018). Antidepressants aim to Organization, 2017). Depression is a common mental disorder, char- correct chemical imbalances of neurotransmitters in the brain that are acterized by persistent sadness and a loss of interest in activities that believed to be responsible for changes in mood and behavior people normally enjoy, accompanied by an inability to carry out daily (Medical News Today, 2018). If a patient feels little or no relief of the activities, for at least two weeks (Kim et al., al.,2015; World Health symptoms after taking antidepressants for several weeks, his or her Organization, 2018). In addition, people with depression normally have psychiatrist can alter the dose of the medication, add another anti- several of the following symptoms: a loss of energy, anxiety, feelings of depressant, or replace it with a new antidepressant (American Psychiatric worthlessness, guilt or even having thoughts of self-harm or suicide Association, 2018). (American Psychiatric Association, 2013). Fortunately, depression can be Antidepressants can be an effective form of intervention for de- treated by taking antidepressant medication, going to therapies, or a pressive symptoms, but they may also cause side effects. Some studies combination of these treatments (World Health Organization, 2018). suggest that psychotherapy such as cognitive behavior therapy (CBT) is Antidepressants are used to treat clinical depression, and are usually safer than drugs and has equal efficiency (Dines et al., 2014; Felice ⁎ Corresponding author. E-mail address: [email protected] (Z. Bai). https://doi.org/10.1016/j.jad.2019.09.040 Received 21 May 2019; Received in revised form 28 August 2019; Accepted 8 September 2019 Available online 10 September 2019 0165-0327/ © 2019 Elsevier B.V. All rights reserved. Z. Bai, et al. Journal of Affective Disorders 260 (2020) 728–737 et al., 2015; Lazar, 2014; Rodgers et al., 2012). Acceptance and Com- depression using professional scales (e.g., Hamilton depression scale, mitment Therapy (ACT), whose ultimate goal is to improve psycholo- Montgomery and Asberg Depression Rating Scale), regardless of the ethics, gical flexibility, is a representative treatment in the third wave ofCBT gender or age of participants; (2) intervention treatment consisted of ACT (Hayes et al., 1999). ACT is a psychological therapy that encourages without other types of treatment, and the forms of ACT treatment were as participants to change their relationships with their thoughts and follows: individual or group; face to face rather than Internet-based; (3) physical sensations through mechanisms of acceptance, mindfulness The comparison group included active interventions (e.g., CBT) and con- and value-based action (Hayes, 2004). ACT is a transdiagnostic psy- ventional control measures (e.g., a waiting list control); and (4) depression chotherapeutic intervention, based on the Relational Frame Theory was the primary outcome, measured by depression rating scales. (Barnes-Holmes and Roche, 2001). The overall goal of ACT is to in- Duplicates and studies that use other interventions with ACT were ex- crease psychological flexibility, which is the ability to be mindful of cluded. In addition, studies were excluded if important and relevant data experiences in the present moment, in an accepting and nonjudgmental could not be obtained, even after the authors were contacted. Only studies way, while behaving consistently with one's values, even when one's using standardized measures of depression were included, and studies thoughts and feelings oppose taking valued action (Levin et al., 2014). using diagnostic interviews conducted by professionals were excluded. To foster psychological flexibility, according to Grégoire et al. (2017), ACT relies on six interrelated and overlapping processes: acceptance 2.3. Screening and data extraction (i.e., willingness to open fully to unwanted experiences such as difficult thoughts, memories, or emotions), contact with the present moment Studies were selected following the Preferred Reporting Items for (i.e., being mindful and aware of one's experiences), self as context (i.e., Systematic Reviews and Meta-Analyses (PRISMA) guidelines (Liberati et al., maintaining perspective about oneself within one's experiences), cog- 2009). Studies were screened independently by two reviewers, and any nitive defusion (i.e., being able to step back from unwanted experiences disagreement was resolved by discussion between the two reviewers. If without getting stuck in them), committed action (i.e., engaging in consensus could not be reached, a third reviewer was consulted. The titles actions that move toward important aspects of life), and values (i.e., and abstracts identified by the search were reviewed independently bythe staying connected to personal values or areas of life that are important). two reviewers. Articles were screened and selected for full-text review if There have been a number of systematic reviews on ACT during the last they met the selection criteria. decade focusing on a variety of diseases, including psychological and phy- Data extraction followed the Cochrane's guidelines for systematic re- siological illnesses (e.g., Swain et al., 2013; Hann and McCracken, 2014; views (Higgins et al., 2011). Two reviewers extracted data separately, and Montgomery et al., 2011). Previous systematic reviews investigating po- any disagreement was resolved by discussion or consultation with a third pulations with depression/anxiety have provided evidence for the effec- reviewer. The following study information was recorded: year of pub- tiveness of ACT as a psychological intervention for depression (e.g., Jiménez lication, characteristics of participants, sample size, specific treatment for et al., 2012; Powers et al., 2009), but only one of them looked at rando- the intervention and control groups, rating scales, and follow-up. Authors mized control trials (RCTs; Hacker et al., 2016), and the authors found that were contacted to obtain missing or unclear data for further analyses. ACT had at least moderate pre-post effects for symptom reduction for both anxiety and depression. However, Hacker et al. (2016) did not conduct 2.4. Assessment of risk of bias subgroup analysis in terms of follow up and degree of depression. During the last four years, there has been a strong increase in RCTs Based on Zeng et al. (2015), which systematically reviewed