Objective: Trichotillomania and skin-picking disorder are underrecognized and often disabling conditions in which individuals repeatedly pull at their hair or pick at their skin, leading to noticeable hair loss or tissue damage. To date there is a severe paucity of evidence-based treatments for these conditions. In this study, the authors sought to determine whether memantine, a glutamate modulator, is more effective than placebo in reducing hair-pulling and skin-picking behavior. Methods: One hundred adults with trichotillomania or skin-picking disorder (86 women; mean age, 31.4 years [SD=10.2]) were enrolled in a double-blind trial of memantine (dosing range, 10–20 mg/day) or placebo for 8 weeks. Participants were assessed with measures of pulling and picking severity. Outcomes were examined using a linear mixed-effects model. The prespecified primary outcome measure was treatment-related change on the NIMH Trichotillomania Symptom Severity Scale, modified to include skin picking. Results: Compared with placebo…