Trichotillomania in bipolar spectrum adolescents is associated with an affective dysregulation phenotype: a multidimensional and cluster-analytic study.

Trichotillomania (TTM) is a body-focused repetitive behavior that may function as an affect regulation strategy. In bipolar-spectrum youth, persistent emotion regulation difficulties may be particularly relevant for early recognition and intervention. In a cross-sectional design, euthymic adolescents with bipolar disorder and a documented lifetime history of TTM (BD+TTM) were compared with euthymic adolescents with bipolar disorder and no lifetime TTM (BD-only) and age- and sex-matched healthy controls (40 participants per group). None of the BD+TTM participants had active hair-pulling at assessment; lifetime TTM severity was scored on the National Institute of Mental Health Trichotillomania Symptom Severity Scale (NIMH-TSS) retrospectively, anchored to the period of greatest historical severity, on the basis of structured caregiver-and-youth interviews and chart review. Participants completed clinician-rated measures of manic symptoms and self-reported measures of depressive symptoms, impulsivity, and emotion regulation difficulties. Group differences were examined with effect-size estimates, and data-driven K-means clustering was used to identify symptom profiles within the full sample. Within the BD+TTM group, correlational and regression analyses tested independent correlates of retrospectively scored lifetime TTM severity. Emotion regulation difficulties showed a graded increase from healthy controls to BD-only to BD+TTM. Retrospectively scored lifetime TTM severity was strongly associated with emotion regulation difficulties and, in multivariable models adjusted for medication load, emotion regulation difficulties were the only independent correlate. Clustering identified an affective-dysregulation profile in which lifetime TTM severity was highest. In bipolar-spectrum youth, a documented lifetime history of TTM appears to mark a clinically meaningful affective-dysregulation phenotype. Because TTM was documented historically rather than assessed during active symptoms, findings are correlational and hypothesis-generating; early dimensional assessment of emotion regulation difficulties may nonetheless help guide mechanism-focused interventions.