A quality-based review of randomized controlled trials of cognitive-behavioral therapy for depression: an assessment and metaregression.

OBJECTIVE: The authors assessed the methodological quality of randomized controlled trials of cognitive-behavioral therapy (CBT) for depression using the Randomized Controlled Trial Psychotherapy Quality Rating Scale (RCT-PQRS). They then compared the quality of CBT trials with that of psychodynamic therapy trials, predicting that CBT trials would have higher quality. The authors also sought to examine the relationship between quality and outcome in the CBT trials.

METHOD: An independent-samples t test was used to compare CBT and psychodynamic therapy trials for average total quality score. Metaregression was used to examine the relationship between quality score and effect size in the CBT trials.

RESULTS: A total of 120 trials of CBT for depression met inclusion criteria. Their mean total quality score on the RCT-PQRS was 25.7 (SD=8.90), which falls into the lower range of adequate quality. In contrast to our prediction, no significant difference was observed in overall quality between CBT and psychodynamic therapy trials. Lower quality was related to both larger effect sizes and greater variability of effect sizes when analyzed across all available comparisons to CBT.

CONCLUSIONS: On average, randomized controlled trials of CBT and of psychodynamic therapy did not differ significantly in quality. In CBT trials, low quality appeared to reduce the reliability and validity of trial results. These findings highlight the importance of discerning quality in individual psychotherapy trials and also point toward specific methodological standards for the future.