The relationship between treatment integrity and outcome in group psychotherapy: A systematic review

Treatment integrity is defined as the extent to which the treatment has been implemented according to a specific theoretical model. It consists of two components: adherence, that is, the degree to which the therapist implements the techniques prescribed by the theoretical model, and competence, that is, the degree to which the therapist skilfully and appropriately implements the techniques prescribed by the model. Recently, the issue of integrity is gaining increasing importance in psychotherapy research, especially in an attempt to clarify its role in influencing the effectiveness of treatments. However, most studies focus on the individual setting. Therefore, this systematic review aims at investigating the relationship between integrity and outcome in group clinical treatments. Results highlighted a positive relationship between group treatment integrity and outcome. Moreover, this review provided insights for implications for research, clinical practice, and training of therapists, identifying questions that still need to be answered and tracing possible future research directions.