Efficacy of internet-based acceptance and commitment therapy for depressive symptoms, anxiety, stress, psychological distress, and quality of life: A systematic review and meta-analysis (Preprint)

BACKGROUND Acceptance and commitment therapy (ACT) is an empirically supported transdiagnostic approach that involves mindfulness processes and behavior change processes for valued living. OBJECTIVE This systematic review and meta-analysis of randomized controlled trials (RCTs) aimed to assess the efficacy of internet-based ACT (iACT) for depressive symptoms, anxiety, stress, psychological distress, and quality of life. METHODS PubMed, CINAHL, PsycINFO, and SCOPUS databases were searched to identify relevant RCTs published up to June 5, 2021. The included RCTs were assessed using the Cochrane Collaboration risk-of-bias tool. Use of either a random-effects model or fixed-effects model was determined by I2 statistic values for heterogeneity. Subgroup analyses were conducted according to the type of control groups, the use of therapist guidance, delivery modes, and the use of targeted participants, when applicable. RESULTS Thirty-nine RCTs met the eligibility criteria. Meta-analyses found small effects of iACT on depressive symptoms, anxiety, stress, psychological distress, and quality of life at the immediate posttest and follow-up, except for stress at follow-up. Subgroup analyses showed small to medium effects of iACT on all the outcomes at the immediate posttest and follow-up compared to passive control groups. On the other hand, subgroup analyses that compared iACT to active control groups found no differences between groups on stress, psychological distress, and quality of life at the immediate posttest or on depressive symptoms, anxiety, and stress at follow-up. In addition, subgroup analyses conducted according to the use of therapist guidance, delivery modes, and the use of targeted participants found no statistically significant subgroup difference among studies in all the outcomes except for the subgroup difference among studies according to the use of targeted participants for depressive symptoms at the immediate posttest (ie, a statistically significant, larger effect of iACT when studies targeted people with depressive symptoms). The overall risk of bias across studies was unclear. CONCLUSIONS Findings of this study contribute to the body of evidence regarding effects of iACT on depressive symptoms, anxiety, stress, psychological distress, and quality of life and may be applicable in any population as ACT is a transdiagnostic approach. This study found that relatively fewer studies were conducted to compare iACT to active control conditions. There were 2 to 5 times more studies that compared iACT to passive control conditions than those that compared iACT to active control conditions in all the outcomes, except for anxiety at follow-up. There were fewer studies that compared iACT to active control conditions, especially for stress and psychological distress at the immediate posttest and follow-up. Future high-quality studies are needed to better understand whether iACT is comparable or superior to other evidence-based treatments, such as cognitive behavioral therapy, in decreasing depressive symptoms, anxiety, stress, and psychological distress and improving quality of life.