No gender differences in placebo responses of patients with major depressive disorder.

Background: This study was designed to compare placebo responses in men and women.

Methods: Data for 501 women and 375 men with major depressive disorder treated with placebo from seven investigational randomized double-blind trials comparing fluoxetine with placebo were analyzed. Changes in major depressive disorder symptoms with placebo administration were measured as changes in total Hamilton Depression Rating Scale scores and adverse (nocebo) effects were measured by comparing treatment-emergent signs and symptoms.

Results: Both women and men with major depressive disorder showed significant symptomatic improvement following placebo administration, similar in magnitude and time course of response. Women on placebo reported slightly more nocebo effects than men.

Conclusions: The finding that women and men with major depressive disorder demonstrated a similar therapeutic outcome after placebo administration suggests that gender is not a predictor of placebo response.