Developing and Evaluating a Situated Assessment Instrument for Trichotillomania: The SAM2 TAI.

Measuring trichotillomania is essential for understanding and treating it effectively. Using the Situated Assessment Method (SAM2), we developed a psychometric instrument to assess hair pulling in situations where it occurs. In two studies, pullers evaluated their pulling in relevant situations, along with how much they experience factors that potentially influence it (e.g., external triggers, reduction in negative emotion, negative self-thoughts). Individual measures of pulling, averaged across situations, exhibited high test reliability, construct validity, and content validity. Large differences between situations in pulling were observed, along with large individual-situation interactions (with limited evidence distinguishing focused versus automatic pulling subtypes). In linear regressions for individual participants, factors that influence pulling tended to correlate with pulling as predicted, explaining a median 74%-83% of its variance. By identifying factors that predict pulling for each individual across situations, the SAM2 Trichotillomania Assessment Instrument (TAI) offers a rich understanding of an individual's pulling experience, potentially supporting individualized pulling interventions.