Acceptance and Commitment Therapy-Specific Processes in the Psychotherapeutic Treatment of Obsessive Compulsive Disorder: A Single Case Study

Abstract

This single case study describes acceptance and commitment therapy (ACT) with exposure and response prevention (ERP) used with a client presenting with symptoms of obsessive compulsive disorder (OCD). Standardized and idiographic outcome measures, including OCD-specific measures (Brief Yale-Brown Obsessive Compulsive Scale; Obsessional Compulsive Inventory), general measures of well-being and risk (CORE Outcome Measure; Outcome Rating Scale), an idiographic measure (Easy Personal Questionnaire), and a Sessional Rating Scale, were used across baseline and treatment phases. Statistical measures of reliable and clinical change were calculated, and client perspective on change was sought through interview. Cause–effect analysis was used to evaluate the extent to which therapeutic change was due to ACT-specific processes. Results showed reliable positive change with a probability of p < .05 across measures, and clinical change in three of five of the measures in which it could be calculated. The client reported improvements in well-being and the extent to which she lives her life according to her values. ACT-specific processes as well as generic therapy processes influenced change. The client’s own strengths and personal contributions to therapy played a major role in her achievement of therapeutic goals. The use of ACT with ERP in treating OCD and collaborative use of outcome measures with careful evaluation are recommended to clinicians.