Venlafaxine vs. paroxetine in the acute phase of treatment for major depressive disorder among Han Chinese population in Taiwan

Purpose: Clinical studies have suggested that venlafaxine induces a higher remission rate than paroxetine. However, very few studies have evaluated relapse episodes over treatment periods longer than a few weeks, and the cut-off score of 7 on the Hamilton Rating Scale for Depression (HRSD) often used to define remission is too high. This score is associated with the high rates of social function impairment. We report on a single centre, open-label, prospective 24-week study to investigate the comparative efficacy of acute treatments with venlafaxine and paroxetine, using different definitions of response and remission rates. Methods: Outpatients satisfying DSM-IV criteria for major depression with a baseline HRSD17 score of at least 16 were eligible. Following baseline evaluations, the patients were assigned to receive venlafaxine 75-225 mg/day with the mean dosage 141.35 +/- 26.98 (SD) mg/day (n = 78), or paroxetine 20 mg/day (n = 92) for 24 weeks. Efficacy was assessed using the mean change in HRSD17 score from baseline, the response rate and the remission rates based on different criteria for remission (HRSD17 score <= 7 or 5). Results: One hundred and seventy patients were evaluated for efficacy; 78 treated with venlafaxine and 92 with paroxetine. Over the treatment period, venlafaxine was comparable with paroxetine on most outcome measures, whereas paroxetine produced significantly higher remission rates at weeks 4, 8, 16, 20 and 24 weeks when the lower cutoff of 5 was used. Conclusions: Venlafaxine treatment was similar to paroxetine according to the typical efficacy measures for treating outpatients with major depression. However, based on the stricter remission criterion, paroxetine might be superior to venlafaxine.