Motor inhibition in trichotillomania and obsessive-compulsive disorder.

We investigated motor inhibition abilities in trichotillomania (TTM) and obsessive-compulsive disorder (OCD), two disorders characterized by repetitive, intentionally performed behaviors. Performance in a GoNogo experiment of 25 TTM and 21 OCD participants was compared to the performance of 26 HC participants. In contrast to OCD and HC participants, TTM participants tended to perform either 'fast and inaccurate' (indicating poor motor inhibition) or 'slow and accurate'. TTM participants with poor motor inhibition reported a significantly earlier age of TTM onset than those TTM participants who performed well. There was no evidence for motor inhibition deficits in OCD. Based on our data, a subgroup of TTM sufferers seems to be characterized by motor inhibition deficits.