Trichotillomania (TTM) is a psychodermatologic disorder that is typically first seen in the dermatology clinic. There are no reported studies of TTM from nationally representative samples. The authors examined epidemiologic and clinical characteristics of an estimated 695,588±136,456 (unweighted count = 89) patient visits with physician-diagnosed TTM (using International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] code 312.39) from a nationally representative US sample. An estimated 20.6%±7.4% visits for TTM were by patients 12 years and younger and demonstrated no sex difference (P=.52). Overall, TTM patients were younger (mean age: 24.01±3.09 years) (P<.001) and more likely to be female (80.3%±6.2%) (P=.003). These demographic findings are consistent with standard diagnostic criteria for TTM (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition). There were no racial (white vs nonwhite) differences in TTM frequency. Psychiatric disorders were seen in 75.5%±9.1% of TTM patient visits, with depressive disorder being the most common comorbidity (37.8%±9.5%) and selective serotonin reuptake inhibitor antidepressants the most commonly (50.6%±9.7%) used medication. These findings highlight the importance of psychiatric comorbidity in TTM.