An A-B-C model of habit disorders: hair-pulling, skin-picking, and other stereotypic conditions.

Severe hair-pulling is characteristic of trichotillomania, an impulse control disorder not otherwise classified. Other pathological habits, including severe nail-biting and skin-picking, are also prevalent and are potentially diagnosable as stereotypic movement disorder. There is increasing awareness of the morbidity associated with these kind of habit disorders but, to date, relatively few randomized controlled trials of pharmacotherapy or psychotherapy have been undertaken. Advances in the understanding of the underlying cognitive-affective mechanisms driving stereotypies in animals and humans may ultimately lead to new approaches. An affect regulation, behavioral addiction, and cognitive control (A-B-C) approach is outlined to conceptualizing and managing these conditions.