The Bergen 4-day treatment for OCD: four years follow-up of concentrated ERP in a clinical mental health setting.

There are few long-term follow-up studies on psychological treatment of anxiety disorders carried out in clinical mental health settings, so called effectiveness studies. The present paper presents a four year follow-up of patients with obsessive-compulsive disorder treated by the Bergen 4-day treatment (B4DT), a concentrated form of exposure and response prevention (ERP). A total of 77 obsessive-compulsive disorder (OCD) patients received treatment during four consecutive days and were assessed with the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) pre, post, and at follow-ups after 3 and 6 months, and 4 years post-treatment. The Y-BOCS mean score changed from 25.9 at pre- to 10.0 post-treatment and 9.9 at long-term follow-up. The proportion fulfilling the strict international consensus criteria for remission was 73% at post-treatment and 69% at follow-up. When taking declining rate, attrition rate, remission, relapse, and further improvement during the follow-up period into account, 72% were recovered on a long-term basis. A comparison with previously published effectiveness studies of ERP indicated that the 4-day treatment yielded significantly higher proportions of remission at post-treatment and recovery at follow-up, as well as within-group effect size on the Y-BOCS. The implications of these results are discussed.