Is mirtazapine augmentation effective for patients with obsessive-compulsive disorder who failed to respond to sertraline monotherapy? A placebo-controlled, double-blind, clinical trial.

Mirtazapine upsurges serotonergic activity by a mechanism different from reuptake inhibition. Our aim is to assess the efficacy of mirtazapine augmentation for patients with obsessive-compulsive disorder (OCD) who did not respond to sertraline monotherapy. Sixty-one patients suffering from OCD who were resistant to sertraline monotherapy were randomly allocated to receive mirtazapine (mean dosage = 39.56 mg/day) or placebo plus their current anti-OCD treatment (sertraline: average dose = 251.37 mg/day and 255.10 mg/day in the mirtazapine and placebo groups, respectively; P = 0.871). The primary outcome was OCD symptom severity as measured by Yale-Brown Obsessive-Compulsive Scale (YBOCS). Forty-five patients (22 in the mirtazapine group and 23 in the placebo group) completed the trial. Average YBOCS score decreased in the mirtazapine group from 27.14 ± 8.05 at baseline to 11.13 ± 4.27 at week 12. In the placebo group, average YBOCS score declined from 28.15 ± 3.27 at baseline to 18.94 ± 3.88 at week 12. Nine patients (40.90%) in the mirtazapine group and only one patient (4.34%) in the placebo group revealed at least a 35% decrease in YBOCS ( P < 0.000). We found that mirtazapine adds to the effect of sertraline in improving obsessive and compulsive symptoms in OCD patients.