Cognitive behavioral therapies are evidence-based – based on what? A systematic review and meta-analysis of recent randomized controlled trials of cognitive behavioral therapies for depression

BACKGROUND: We aimed to map the last five years' randomized controlled trials (RCTs) of cognitive behavioral therapies (CBTs) for depression to determine what types of CBTs are currently being investigated and how they are evaluated. METHODS: As per the pre-registration (Prospero; #CRD42023427902), RCTs of CBTs for depression (2019 through 2023) were identified from searches in PubMed and PsycINFO. We reviewed the type of CBT, outcome (e.g., positive outcomes, neuropsychological performance), frequency, and efficacy, in addition to the assessment of moderation, mediation, and adverse events. RESULTS: 78 records, representing 62 independent samples, fulfilled the inclusion criteria. CBTs were most often of a contemporary type (51 %) and the mean attrition rate post-treatment was 21 %. Fifty-nine studies (95 %) included a measure of depressive symptoms. Positive (74 %) and negative outcomes (65 %) were also frequently investigated. Harm and adverse events were evaluated in 40 studies (65 %). The post-treatment effects were of medium-to-large magnitudes (Hedges' g: 0.51 to 0.81). At follow-up, the effect either remained of the same size or decreased to a small magnitude. No differences were observed between classic (g = 0.52) and contemporary (g = 0.60) CBTs. DISCUSSION: These results show the current landscape of RCTs of CBT for depression, revealing what clients can expect in terms of effects and what researchers are currently emphasizing - and ignoring - in trial evaluations. The findings may guide future studies in closing the gaps in current research. The present study was limited to samples with a formal diagnosis of depression and superiority trials, and results should be interpreted accordingly.