Assessment of Trichotillomania: A Psychometric Evaluation of Hair-Pulling Scales

Currently there is no gold standard treatment outcome measure for trichotillomania (TTM), a disorder characterized by repetitive hair pulling resulting in noticeable hair loss. The goal of the current study was to evaluate the psychometric properties of TTM measures of differing assessment methods: self-report, clinician-rated summary scales, and clinician-rated global severity scales. Data collected from 28 patients with TTM indicated mixed psychometric properties for current scales. Internal consistency was strong for self-report but not clinician-rated summary scales. One clinician-rated summary scale total and subjective ratings of hair loss demonstrated good interrater agreement. Although convergent validity was good within measurement type, self-report did not correlate with clinician-rated global severity scales, perhaps because of absence of hair loss severity assessment on the self-report measure. A multimethod assessment including one of each type of measure reviewed in this paper, along with self-monitoring and measures of hair loss severity, is recommended for a comprehensive best practice approach to TTM assessment.