Functional brain imaging and pharmacotherapy in social phobia: single photon emission computed tomography before and after treatment with the selective serotonin reuptake inhibitor citalopram.

1. Despite increased understanding of the prevalence and pharmacotherapy of social phobia (or social anxiety disorder), the neurobiology of the disorder is little understood. 2. Little data exists on the effect of pharmacotherapeutic intervention on regional cerebral blood flow (rCBF) in this disorder. Patients (n=15) who met DSM-IV diagnostic criteria for social phobia were subjected to single photon emission computed tomography (SPECT) with technetium-99m hexamethylpropylene amine oxime (Tc-99m HMPAO) before and after an eight-week trial of pharmacotherapy with the selective serotonin reuptake inhibitor (SSRI) citalopram. 3. Pharmacotherapy led to significantly reduced activity in the anterior and lateral part of the left temporal cortex; the anterior, lateral and posterior part of the left mid frontal cortex; and the left cingulum. 4. Despite the small sample size, medication non-responders (n=6) had higher activity at baseline in the anterior and lateral part of the left temporal cortex and the lateral part of the left mid frontal regions compared with responders (n=9). These data from this exploratory study are consistent with work suggesting that the anxiety disorders share certain mediating neurocircuitry, although activity in other brain regions may differ. 5. Further research is necessary to determine the neurobiological underpinnings of social phobia.