Familial trichotillomania: role of genetic factors in the determination of subtypes.

OBJECTIVES: Trichotillomania (TTM) is a psychiatric syndrome characterised by the inability to control repetitive hair pulling. Psychiatric data reveal that TTM is not usually prevalent among all family members of patients, and so far only one case of familial TTM has been reported. METHODS: In this study, we report a case of familial TTM that afflicted four sisters and discuss the importance of genetic factors in this disorder. RESULTS: This report suggests that, similar to many other psychiatric disorders, TTM can be detected in other family members and that genetic factors not only have a significant role in the development of such disorders but also in determination of the disorder subtype. This report also shows that the comorbidities in one member of the family might predict the existence of comorbidities in other members. On the basis of response to medication. CONCLUSION: the authors suggest that a genetic disorder like polymorphism in serotonin receptors or dopamine can cause such a disorder.