Serotonergic function in social phobia: comparison to normal control and obsessive-compulsive disorder subjects.

Eighteen patients with social phobia, 21 normal control subjects, and 42 obsessive-compulsive disorder (OCD) control subjects were challenged with single doses of the partial serotonin agonist oral m-chlorophenylpiperazine (m-CPP) and placebo. Social phobics did not significantly differ from normal or OCD control subjects in prolactin response to m-CPP. There was a significant difference across groups in cortisol response to m-CPP, such that female social phobics had more robust cortisol responses to the m-CPP challenge. Pairwise comparisons only reached trend significance, perhaps due to the relatively small sample sizes. This study offers preliminary evidence for serotonin dysfunction in social phobia, particularly in female social phobics, but needs to be replicated in a larger sample size.