Oral Scopolamine Augmentation in Moderate to Severe Major Depressive Disorder: A Randomized, Double-Blind, Placebo-Controlled Study

Objective: To evaluate the antidepressant effect of oral scopolamine as an adjunct to citalopram.

Method: In this randomized double-blind placebo-controlled study, patients were assessed in the outpatient clinics of 2 large hospitals from November 2011 to January 2012. Forty patients (18-55 years) with major depressive disorder (DSM-IV-TR criteria) and 17-Item Hamilton Depression Rating Scale (HDRS) score ≥22 were randomly assigned to scopolamine hydrobromide (1 mg/d) (n=20) or placebo (n=20) in addition to citalopram for 6 weeks. HDRS score was measured at baseline and days 4, 7, 14, 28, and 42. The primary outcome measure was HDRS score change from baseline to week 6 in the scopolamine group versus the placebo group. Response was defined as ≥50% decrease in HDRS score; remission, as HDRS score ≤7.

Results: Augmentation with scopolamine was significantly more effective than placebo (F1,38=5.831, P=.021). Patients receiving scopolamine showed higher rates of response (65%, 13/20 at week 4) and remission (65%, 13/20 at week 6) than the placebo group (30%, 6/20 and 20%, 4/20, respectively; P=.027, P=.004, respectively). Patients in the scopolamine group showed higher rates of dry mouth, blurred vision, and dizziness than the placebo group.

Conclusions: Oral scopolamine is a safe and effective adjunct for treatment of patients with moderate to severe major depressive disorder.

Trial Registration: Iranian Registry of Clinical Trials identifier: IRCT201201181556N31

J Clin Psychiatry

© Copyright 2012 Physicians Postgraduate Press, Inc.

Submitted: February 17, 2012; accepted June 18, 2012.

Online ahead of print: October 16, 2012 (doi:10.4088/JCP.12m07706).

Corresponding author: Prof. Shahin Akhondzadeh, PhD, Psychiatric Research Center, Roozbeh Psychiatric Hospital, Tehran University of Medical Sciences, South Kargar St, Tehran 13337, Iran ([email protected]).