Clinician-rated measures of hair pulling: A preliminary psychometric evaluation

Trichotillomania (TM) typically is assessed using adaptations of clinician-rated scales for obsessive-compulsive disorder (OCD). The present preliminary study examined the psychometric properties of four OCD-based clinician-rated scales [i.e., the Yale-Brown Obsessive Compulsive Scale - Trichotillomania (YBOCS-TM), the Psychiatric Institute Trichotillomania Scale (PITS), and the NIMH Trichotillomania Severity and Impairment Scales] of TM symptoms. Descriptive data, interrater agreement, internal consistency, and concurrent validity were evaluated in a sample of 22 individuals with a principal diagnosis of TM. Mixed psychometric evidence was found regarding the utility of OCD-based scales for assessing TM symptomatology, although conclusions are limited based on small sample sizes. Interrater agreement generally was acceptable for all PITS items and for both item and summary scores for the YBOCS-TM Behavior Subscale. For all four clinician-rated scales, however, estimates of internal consistency were below minimally acceptable levels. Examination of scale validity was limited given some difficulties with reliability, although data suggested potential support for concurrent agreement between some item and summary scores with external criteria based on self-monitoring of hair pulling. Despite limitations due to the small sample size, the data provide useful preliminary information about the clinical evaluation of TM. Implications for future research, most notably development of new TM scales, are discussed.