Sustained response versus relapse: the pharmacotherapeutic goal for obsessive-compulsive disorder

Convincing evidence from placebo-referenced randomized controlled trials supports efficacy for clomipramine and selective serotonin reuptake inhibitors for acute treatment of obsessive-compulsive disorder. It remains less conclusively understood whether these agents maintain efficacy over the longer term. This paper systematically reviews long-term medication studies in obsessive-compulsive disorder. Studies of clomipramine, fluoxetine and sertraline investigated 'responders' from acute treatment trials and extended treatment up to 12 months versus placebo. Responses to medication were sustained. A 24-week placebo-controlled trial of escitalopram (10 mg or 20 mg/day) and paroxetine (40 mg/day) demonstrated ongoing efficacy for all three treatments. Studies that randomized treated cases to placebo demonstrated reemergence of symptoms in the placebo-treated cohort. Six relapse prevention trials were found by systematic search. Some, but not all, revealed significant advantages for remaining on medication. Paroxetine (20-60 mg/day) and escitalopram (10 or 20 mg/day) were each found to outperform placebo in preventing relapse during 24 weeks of double-blind, randomized follow-up. Meta-analysis, using Review Manager software (4.2.8), detected overall superiority of selective serotonin reuptake inhibitors to placebo in preventing relapse among adult treatment-responders. Worsening by five Yale-Brown Obsessive Compulsive Scale points emerged from the review as a suggested threshold for relapse. Viewed collectively, these results suggest that selective serotonin reuptake inhibitors are effective long-term treatments and relapse prevention represents the treatment target for obsessive-compulsive disorder.