Objective: To review the last decade of behaviour therapy research in obsessive-compulsive disorder (OCD). Method: The most salient research was analyzed. Results: Many studies confirmed that exposure and ritual prevention (ERP) effectively reduced compulsive rituals and obsessive thoughts in most patients in all age groups, although a minority of the patients did not complete treatment. Gains persisted to follow-up 2 to 6 years later in several countries. Improvement after ERP generalized to obsessive-compulsive beliefs, mood, work, and social adjustment, and was accompanied by reduction in cerebral bloodflow in the right caudate nucleus. Teaching patients how to prevent relapse seems to reduce the risk of recurrence. ERP yields slightly more improvement than does appropriate antidepressant medication and is followed by far less relapse after treatment has stopped so ERP may be more cost-effective in the long term. Antidepressant medication is a useful adjunct to ERP when OCD is accompanied by comorbid depression. The therapist now tends to teach patients how to carry out self-exposure and self-imposed ritual prevention rather than to impose ERP on them. Self-help manuals help patients to do this, and computer aids to allow patients to learn how to do ERP at home have been valuable in pilot studies. Cognitive therapy without ERP was as useful as ERP. Conclusion: ERP is of lasting value for OCD. Long-term cost-effectiveness comparisons are needed of self-administered ERP versus cognitive therapy and versus medication. Studies are also needed of brief psychological treatment for depression comorbid with OCD.
