Body-focused repetitive behavior disorders (BFRBs) include Trichotillomania (TTM; Hair pulling disorder) and Excoriation (Skin Picking) Disorder (SPD). These conditions are prevalent, highly heterogeneous, under-researched, and under-treated. In order for progress to be made in optimally classifying and treating these conditions, it is necessary to identify meaningful subtypes. 279 adults (100 with TTM, 81 with SPD, 40 with both TTM and SPD, and 58 controls) were recruited for an international, multi-center between-group comparison using mixture modeling, with stringent correction for multiple comparisons. The main outcome measure was to examine distinct subtypes (aka latent classes) across all study participants using item-level data from gold-standard instruments assessing detailed clinical measures. Mixture models identified 3 subtypes of TTM (entropy 0.98) and 2 subtypes of SPD (entropy 0.99) independent of the control group. Significant differences between these classes were identified on measures of disability, automatic and focused symptoms, perfectionism, trait impulsiveness, and inattention and hyperactivity. These data indicate the existence of three separate subtypes of TTM, and two separate subtypes of SPD, which are distinct from controls. The identified clinical differences between these latent classes may be useful to tailor future treatments by focusing on particular traits. Future work should examine whether these latent subtypes relate to treatment outcomes, or particular psychobiological findings using neuroimaging techniques.

Department of Psychiatry and Behavioral Neuroscience University of Chicago Chicago IL USA

Department of Psychiatry and Biobehavioral Sciences University of California Los Angeles CA USA

Department of Psychiatry Massachusetts General Hospital and Harvard Medical School Boston USA

Department of Psychiatry University of Cambridge Cambridge UK

Department of Psychiatry University of Cambridge Cambridge UK; Department of Kinanthropology Charles University Prague Czech Republic

Department of Psychiatry University of Stellenbosch South Africa

Department of Psychology Marquette University Milwaukee WI USA

SA MRC Unit on Risk and Resilience in Mental Disorders Dept of Psychiatry and Neuroscience Institute University of Cape Town South Africa

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