What does the LAC depression study really show?: Critical considerations of the methodology

Abstract

Background: Cognitive behavioral and psychodynamic therapy methods are in competition as far as evidence for their effectiveness is concerned. Although there have already been comparative efficacy studies, these often do not reflect the care situation in Germany. At the beginning of the year, the results of the LAC depression study were presented, which compares these two methods in a naturalistic study. These results suggest equal effectiveness of cognitive behavioral therapy (CBT) and psychoanalytic therapy (PAT). Material and method: A critical appraisal of several research articles published on the results of the LAC depression study, alternative presentation of the primary outcome measures relative to the number of treatment sessions. Results: The LAC depression study deviated at decisive points from the previously published trial protocol. The use of CBT achieved the same results with significantly fewer therapy sessions. The experimental design and the sample size achieved are unsuitable for demonstrating the effects suspected in the hypotheses. Conclusion: Due to methodological problems, significant deviations from the study protocol and strong dose-response differences, the results of this study cannot be interpreted as evidence of a supposedly equal efficacy of PAT and CBT.