Issues in the pharmacological treatment of obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) preferentially responds to a class of antidepressants called serotonin reuptake inhibitors (SRI). This review discusses certain issues unique to pharmacological treatment of OCD: choice of SRI, dose and duration of treatment, options after first failed SRI trial and treatment of SRI non-responders.

We performed a MEDLINE search for pharmacotherapy studies published until December 2006. In addition, the reference sections of major articles, and reviews were also screened. We also considered clinical guidelines and narrative reviews in writing this review.

The SRIs are equally effective in treating OCD. Meta-analyses suggest that clomipramine may be superior to other SRIs. OCD tends to respond to higher doses of SRIs than that used to treat depression. Response to treatment is usually delayed and may take up to 8-12 weeks. Atypical antipsychotics are the only proven augmenting agents in SRI non-responders. Cognitive behaviour therapy (CBT) is an effective treatment strategy in treating OCD and possibly has a role in treating SRI non-responders.

Side effect profile and drug-drug interactions largely determine the choice of SRI. Those who fail to respond to one SRI trial may well respond to another SRI trial. Clomipramine is recommended if 2-3 trials of SRIs fail to produce response. Atypical antipsychotics are the first-line augmenting agents in SRI non-responders. CBT should be considered in all patients with OCD and is a potential option in SRI non-responders.

OCD is a chronic and debilitating disorder. In responders, SRIs have to be continued in the same doses (if possible) for a minimum of 1-2 years and may be lifelong in those with persistent symptoms and in those with multiple relapses. CBT has to be offered in combination with SRIs wherever facilities for CBT exist.