How to Define, Find and Classify Side Effects in Psychotherapy: From Unwanted Events to Adverse Treatment Reactions

OBJECTIVE: Empirical research on the negative effects of psychotherapy is insufficient, partly because there is a lack of theoretical concept on how to define, classify and assess psychotherapy side effects. This paper proposes a model for the definition, classification and assessment of psychotherapy side effects. METHOD: Definitions are provided for 'unwanted events', 'treatment-emergent reactions', 'adverse treatment reactions', 'malpractice reactions', 'treatment non-response', 'deterioration of illness', 'therapeutic risks' and 'contraindications'. We describe processes analysing the causality of negative events and the correctness of treatment. RESULT: A procedural model on how to find, classify and evaluate negative events is described, the unwanted event to adverse treatment reaction (UE-ATR) checklist. CONCLUSION: Recognition of adverse treatment effects is a characteristic of good therapists and treatments. Psychotherapists should be sensitive for negative effects. This can help improve the quality of treatment. The UE-ATR checklist can be used in psychotherapy trials, quality assurance, clinical practice and training of psychotherapists.