Background: Retrospective data analyses were conducted of a single-blind trial of 993 outpatients with nonpsychotic major depression (DSM-III-R) treated for 12 weeks with nefazodone to provide a more specific picture of the nature and timing of response or remission to acute-phase treatment.
Method: All patients participated in a single-blind, 16-week lead-in to obtain responders eligible for a subsequent double-blind, randomized continuation phase trial. Outcomes were defined by the 17-item Hamilton Rating Scale for Depression (HAM-D). A > or = 50% reduction from baseline defined response, and a total HAM-D exit score of < or =8 defined remission.
Results: Of all patients who entered the trial, 41.8% (last observation carried forward) responded at or before week 4 (early responders), and an additional 25.2% responded thereafter; 18.3% achieved remission at or before week 4; 33.6% achieved remission after week 4. Thus, 77.3% of those responding ultimately remitted. On average, remission followed response by 2 weeks. The average end-of-treatment dose was 376 mg/day at exit (last observation carried forward). Responders or remitters (as opposed to nonresponders or nonremitters) had lower baseline depressive symptomatology and were more likely to be married or cohabiting.
Conclusion: The full symptomatic benefit of antidepressant medication may not be apparent until completion of an 8- to 10-week trial. A high number of responders ultimately attained remission. Baseline demographic and clinical features were not highly predictive of who would or would not benefit from nefazodone. For routine care, a minimal acute-phase trial, using a 50% reduction in baseline symptom severity to define response, should be 8 weeks. Whether ultimate nonresponders can be identified earlier than 8 weeks deserves further study.