A Double-Blind, Placebo-Controlled Trial of Clonazepam in Obsessive-Compulsive Disorder

Abstract

Selective serotonin reuptake inhibitors (SSRIs) are currently the first-line pharmacological agents in treating obsessive-compulsive disorder (OCD). Appropriate treatment for OCD also involves cognitive behavioural therapy (CBT), including exposure and response prevention. As there is a time delay in seeing full therapeutic response, and not all patients tolerate SSRIs, there remains an unmet need for additional treatment approaches in OCD. In addition, most responders report only a partial reduction in symptoms. Clonazepam has demonstrated effectiveness in several preliminary reports in treating OCD. Twenty-seven patients with OCD were entered into a 10-week, double-blind, parallel design trial of clonazepam vs. placebo. Overall, only 3 out of 25 patients who had ≥ 1 rating on clonazepam/placebo were judged to be treatment responders, by scoring a 1 (very much improved) or 2 (much improved) on the CGI improvement scale. Responders included 2 of 9 in the placebo group and 1 of 16 in the clonazepam group. No significant difference was found between clonazepam and placebo groups on responder/non responder status (X² = 1.39, df = 1,24, p=0.238), nor on change in YBOCS, HAM-A, HAM-D or NIMH scales from beginning to last evaluation carried forward. These findings suggest that clonazepam is not effective as monotherapy in treating OCD. Its effectiveness in specific subgroups of OCD patients with co-morbid anxiety disorders or as an augmentation strategy added to SSRIs remains to be determined.

Key Words:

• clonazepam
• benzodiazepine
• serotonin
• obsessive-compulsive disorder

Additional information

Notes on contributors

Stephen M Stahl

Joyce Laing works in the Department of Child and Family Psychiatry, Playfield House, Cupar, Fife, and is a Consultant Art Therapist to Psychiatric Hospitals and Prisons and Chairwoman of the Scottish Society of Art and Psychology.

Dr Niculescu Dan, Centrul de Reumatologie, Str. J. (F)ucick no. 5, Bucuresti, Romania

Anni Vilppula, Department of Medicine, Paimio Hospital, Preitilä, Finland

G. Tausch, Department of Rheumatology, Municipal Hospital of Vienna-Lainz, Wolkersbergenstraße 1, A-1130Wien, Austria

Dr Guido Gothoni, Medica Pharmaceutical Company Ltd., P.O. Box 325, SF-00101 Helsinki 10, Finland

A. Elman, Dept. of Rheumatology, Karolinska sjukhuset, Stockholm, Sweden

Hannu Paitälä, Rheumatism Foundation Hospital, Heinola, Finland

Jonas Jonsson, National Bacteriological Laboratory, S-105 21 Stockholm, Sweden