Adverse events in psychotherapy randomized controlled trials: A systematic review.

Although evidence for benefits of psychotherapy is substantial, less is known about potential harm. Therefore, we systematically summarized randomized controlled trials (RCTs) to compile evidence-based data on the frequency and characteristics of adverse events (AEs) of psychotherapy. This systematic review of result publications is based on a review of harm consideration in psychotherapy study protocols. On the basis of 115 study protocols, 85 RCTs with 126 psychotherapy and 61 control conditions were eligible for inclusion. The sample consisted of 14,420 participants with the most common mental disorders. Harmful events, e.g., AEs, number of individuals with symptom deterioration, were explicitly reported in 60% of the studies. Conceptualization, recording, and reporting of AEs were heterogeneous. For most reported AEs, the association to study treatment remained unclear. Because the AE recording approaches of the individual studies differed substantially, results could only be compared to a limited extent. Consistent with other findings, this review demonstrates that AEs can be expected to affect more than one in ten participants. Serious AEs occurred more than in one in 21 participants in psychotherapy RCTs. To allow a balanced risk/benefit evaluation of psychotherapy, systematic harm monitoring and reporting should become standard in psychotherapy RCTs.