Rates of Obsessive Compulsive Disorder in first degree relatives of patients with trichotillomania: a research note.

To explore a possible relationship between trichotillomania, (TTM) (compulsive hair pulling) and Obsessive Compulsive Disorder (OCD), 65 out of 69 (94%) first degree relatives of 16 female probands with severe chronic TTM were compared with two control groups for OCD and for TTM. Three (19%) of the 16 TTM probands had at least one first degree relative with a lifetime history of OCD, and there was an age corrected rate of 6.4% of first degree relatives with OCD. No relative in control group (A) met criteria for OCD. There was a trend (Fishers exact p = .07, two tailed) for a higher rate (age corrected) of OCD in TTM families; these pilot data are consistent with the concept of a spectrum of obsessive compulsive disorders which includes TTM and other pathological grooming behaviours.