An inappropriate head covering may signal that a patient is hiding trichotillomania, repetitive hair pulling that causes distress and functional impairment. Patients tend to be highly secretive about the condition and to regard it as shameful. Thus, clinicians should be sensitive as well as observant. While acknowledging the lack of reliable information on trichotillomania, Chamberlain et al. (CME, p. 568) review the existing findings on epidemiology, genetics, comorbidity, neurocognition, brain abnormalities, and treatment. Although trichotillomania is similar phenomenologically to obsessive-compulsive disorder (OCD), hair pulling is usually driven by increasing psychological tension rather than by obsessions. Its epidemiology, brain and neuropsychological dysfunction, and comorbidity also distinguish it from OCD. Treatment is likely to be largely determined by patient preference, as there have been few well-designed comparator trials. Clomipramine and behavior therapy have shown benefits in some comparisons, but fluoxetine has not. Dual therapy with both drug and behavior treatments may work best for some patients.