Duloxetine, an inhibitor of serotonin and norepinephrine reuptake, has been approved for the treatment of major depressive disorder. In this analysis, data from eight, double-blind, placebo-controlled duloxetine trials were pooled, and the response to duloxetine treatment (40-120 mg/day) was compared between patients experiencing their first episode of depression (n=581) or a subsequent episode (n=1321), and between patients experiencing a depressive episode of short (n=596), medium (n=669), or long (n=649) duration based on tertile divisions. Treatment response was determined on the basis of changes from baseline in the 17-item Hamilton Rating Scale for Depression total score, the Clinical Global Impressions of Severity Scale, and painful physical symptoms (Somatic Symptom Inventory and Visual Analog Scales). Overall, changes on all outcome measures and response and remission rates were significantly greater in duloxetine-treated patients than in placebo-treated patients. Furthermore, the effect of duloxetine was similar across all episode characteristic groups (first/subsequent episode, short/medium/long episode duration). Only for the Somatic Symptom Inventory was the effect of duloxetine significantly different between groups (greater in the subsequent episode group than in the first episode group). Duloxetine was effective in the treatment of first and subsequent episodes of major depressive disorder, and regardless of duration of the current depressive episode.