Assessing the unwanted: A systematic review of instruments used to assess negative effects of psychotherapy

Objective: While the efficacy of psychotherapy in the treatment of mental disorders is well examined, systematic research into negative effects of psychotherapy seems comparatively rare. Therefore, this review evaluates instruments for assessing negative effects of psychotherapy in order to create a consensus framework and make recommendations for their assessment. Methods: The study selection procedure follows current best-practice guidelines for conducting systematic reviews, with 10 included studies in three databases (PsycINFO, PubMed, and Web of Science). The nine instruments identified were each critically reviewed concerning the theoretical orientation, including the assessed domains of negative effects, psychometric properties, and diagnostic characteristics. Results: Seventeen domains of negative effects of psychotherapy were identified but inconsistently assessed by the nine instruments. Most instruments provide some initial data on their psychometric properties. Regarding diagnostic characteristics, different item-response formats are used but often with reference to attribution to therapy. Conclusion: This review indicates that the existing instruments for assessing negative effects of psychotherapy cover a wide range of relevant domains without any consensus on the most important ones and their psychometric properties are usually unsatisfactory. A framework for consensus, building on the definition and conceptualization of negative effects, is synthesized, and recommendations for improving the assessment are derived.