The neurobiology and pharmacotherapy of trichotillomania has received increasing attention in recent years. Parallels have been drawn between findings in this disorder and those in obsessive-compulsive disorder (OCD). To date, however, there has been little work on the effect of a pharmacotherapeutic intervention on functional brain imaging in trichotillomania. Female patients (n = 10) with DMS-IV diagnostic criteria for trichotillomania were subjected to single photon emission computed tomography (SPECT) with technetium-99m hexamethylpropylene amine oxime (Tc-99m HMPAO) before and after 12 weeks of pharmacotherapy with the selective serotonin reuptake inhibitor (SSRI), citalopram. Pharmacotherapy led to significantly reduced activity in inferior-posterior and other frontal regions. Correlates of hair-pulling symptoms with regional brain activity differed before and after pharmacotherapy. These data are to some extent consistent with work suggesting that trichotillomania, like OCD, is mediated by corticostriatal circuits. Pharmacotherapeutic response to SSRIs in trichotillomania may not be as robust as in OCD. Further research is necessary to determine the neurobiological underpinnings of these differences.