Rating the severity of trichotillomania: methods and problems.

The capacity to measure the severity of trichotillomania is necessary for studies of the efficacy of treatment interventions. To date, researchers have used diverse methods, including: the adaptation of instruments designed for other purposes, counting episodes of hair pulling, counting hairs that have been pulled out, and both physician- and self-administered scales of severity or improvement. In this paper, the authors review the methods that have been employed, discuss problems in the measurement of trichotillomania, explore the potential for objective measures of hair loss and introduce a new instrument, the Psychiatric Institute Trichotillomania Scale.