Early improvement as a predictor of eventual antidepressant treatment response in severely depressed inpatients.

Abstract

Traditionally, the therapeutic effect of antidepressants is thought to take several weeks. However, several studies found evidence of early drug response occurring within the first 2weeks of antidepressant treatment and that this early onset response may predict eventual treatment outcome. This study aims to investigate the predictive value of early improvement in the course of treatment with imipramine or venlafaxine in an inpatient population with severe major depression. A post hoc analysis was conducted after pooling data from two almost identical trials. The study included 149 patients with DSM-IV diagnosis major depression and a baseline score ≥17 on the 17-item Hamilton Rating Scale for Depression (HAM-D). Patients were randomized for double-blind treatment with either antidepressant. Early improvement (≥25% reduction on HAM-D score) was evaluated after 2weeks and response (≥50% reduction on HAM-D score) after 6weeks of acute treatment. Of 64 patients achieving early improvement, 38 (59%) became responders, whereas of 85 patients not achieving early improvement, only 23 (27%) became responders. There was a significant difference in time to response between patients achieving early improvement and patients not achieving early improvement. Early improvement is a modest sensitive predictor for eventual response. In the present study, although the sensitivity of early improvement was modest, based on the severity of clinical symptoms, a clinician treating a patient with severe major depression may seriously consider changing the treatment at an earlier stage than is presently customary.