In two studies with hair pullers, this work applied the SAM^2 psychometric approach for measuring individual differences across situations to trichotillomania (compulsive hair pulling).

Findings demonstrated large situational effects, along with large situation X individual interactions and trait-level individual differences.

Multiple findings questioned the classic distinction between hairpulling subtypes (e.g., automatic versus focused pullers), indicating that almost all pullers do some of both.

Predictive measures from the Situated Action Cycle assessed how well different theories of trichotillomania in the literature explain pulling.  At the group level, situational triggers, emotion, and reward all predicted pulling behavior highly, accompanied by considerable variation for individual predictor profiles.  At the individual level, these predictors explained a median 74%–83% of the variance across individuals and studies.

Correlations with the classic unsituated measure of pulling (the MGH-HPS) were relatively low.

This article can be accessed at:  https://barsaloulab.org/Online_Articles/2024-Taylor_Browne_Luka_et_al-Assessment-SAM2_trich.pdf