OPTIMAL LENGTH OF CONTINUATION THERAPY IN DEPRESSION - A PROSPECTIVE ASSESSMENT DURING LONG-TERM FLUOXETINE TREATMENT

Objective: The purpose of this study was to determine prospectively th e optimal length of therapy in a long-term, placebo-controlled continu ation study of patients who responded to acute fluoxetine treatment fo r major depression (defined by DSM-III-R). Method: The study was condu cted at five outpatient psychiatric clinics in the United States. Pati ents who met criteria for remission after 12 or 14 weeks of open-label acute fluoxetine therapy, 20 mg/day (N=395 of 839 patients), were ran domly assigned to one of four arms of a double-blind treatment study ( 50 weeks of placebo, 14 weeks of fluoxetine and then 36 weeks of place bo, 38 weeks of fluoxetine and then 12 weeks of placebo, or 50 weeks o f fluoxetine). Relapse rate was the primary outcome measure, Both Kapl an-Meier estimates and observed relapse rates were assessed in three f ixed 12-week intervals after double-blind transfers from fluoxetine to placebo at the start of the double-blind period and after 14 and 38 w eeks of continued fluoxetine treatment. Results: Relapse rates (Kaplan -Meier estimates) were lower among the patients who continued to take fluoxetine compared with those transferred to placebo in both the firs t interval, after 24 total weeks of treatment (fluoxetine, 26.4%; plac ebo, 48.6%), and the second interval, after 38 total weeks of treatmen t (fluoxetine, 9.0%; placebo, 23.2%). In the third interval, after 62 total weeks of treatment, rates were not significantly different betwe en the groups (fluoxetine, 10.7%; placebo, 16.2%). Conclusions: Patien ts treated with fluoxetine for 12 weeks whose depressive symptoms remi t should continue treatment with fluoxetine for at least an additional 26 weeks to minimize the risk of relapse.