Trichotillomania (TTM, repetitive hair pulling) is a complex underdiagnosed syndrome that often causes considerable psychological distress and physical disfigurement. Although many aspects of hair pulling bear similarity to compulsions of obsessive-compulsive disorder (OCD), TTM lacks obsessions associated with OCD. The phenomenology of TTM also is similar to tics in Tourette Syndrome (TS) and overlaps with TS in both limited structural neuroimaging data and in terms of treatment response to pharmacotherapy with dopamine antagonists.
In order to study potential comorbid relationships between TTM, TS, and OCD, a total of 61 patients with either TS, OCD, or OCD comorbid with TS were assessed using structured interviews as part of a phenomenological study of these groups. Post hoc analyses indicated significantly higher proportions of hair pulling in those subjects with OCD comorbid with TS compared to subjects with either OCD or TS alone.
These data, in conjunction with clinical phenomenology, neuroimaging results, and response to pharmacotherapy suggest the possibility that some forms of TTM may be more closely related to tic disorders than OCD. Futher research is needed to clarify and confirm these observations of putative relationships between TTM and TS and potential treatment implications.