OCD: where the serotonin selectivity story begins.

Since concomitant anxiety is frequent and prominent, obsessive-compulsive disorder (OCD) is classified as an anxiety disorder. However, effective antidepressant and anxiolytic agents that are nonserotonin-selective are generally ineffective in significantly reducing OCD symptoms, while the potent serotonin reuptake inhibitor, the tricyclic clomipramine, and several serotonin selective reuptake inhibitors (SSRIs) are efficacious. These results suggest that serotonergic transmission may be important in achieving significant antiobsessive efficacy. Although no significant differences in efficacy between SRIs and SSRIs have been demonstrated in the treatment of OCD, there are important differences in side effect profiles and pharmacokinetic factors. Further research in the treatment of OCD is required on comparative efficacy of SRIs, the choice of SRI agents following initial nonresponse, and effects resulting from the long-term use of SRIs.