Psychometric Evidence of the Trichotillomania Dimensional Scale (TTM-D) in Adults From the General Population

The aim of the present study was to analyse the psychometric properties of the Trichotillomania Dimensional Scale (TTM-D) in Peruvian adults. A total of 507 adults (66.7% women) participated, completing a sociodemographic questionnaire, the Frequency of Suicidal Ideation Inventory (FSII), the Patient Health Questionnaire-2 (PHQ-2), and the Generalized Anxiety Disorder-2 (GAD-2). Structural validity was examined using confirmatory factor analysis within a covariance-based structural equation modelling framework, and item functioning was analysed using a two-parameter item response theory (IRT) model. The TTM-D demonstrated adequate content validity, a unidimensional structure (CFI = .99, TLI = .99, RMSEA = .06 [90% CI: .032, .104], SRMR = .01), and good reliability (ω = .94, H = .98). Moreover, significant associations were observed with depressive symptoms, generalised anxiety, and suicidal ideation. Item 3 showed the highest discrimination and information, and the scale proved accurate at high levels of trichotillomania. In conclusion, the TTM-D exhibits suitable psychometric properties supporting the validity and reliability of score interpretation in the assessment of trichotillomania. Its use is recommended both in professional practice and in research with the general adult population.