Silymarin/Milk Thistle Treatment of Children and Adults with Trichotillomania: A Double-Blind, Placebo Controlled, Cross-Over Study

Abstract

Objective: Data on the pharmacological treatment of trichotillomania are limited. Silymarin (derived from milk thistle) has antioxidant properties, and showed promise in trichotillomania in a prior case report. The goal of the current study was to determine the efficacy and tolerability of silymarin in children and adults with trichotillomania. Methods: 20 individuals (19 [95.0%] women; 16 adults; mean age = 27.9 [11.5] years) with trichotillomania entered a 12-week, double-blind, placebo-controlled cross-over study (6 weeks of silymarin and 6 weeks of placebo with a one-week wash-out in between). Dosing of silymarin ranged from 150mg bid to 300mg bid. Subjects were assessed with the NIMH Trichotillomania Severity Scale (primary outcome), the Massachusetts General Hospital Hair Pulling Scale, Clinical Global Impression scale, and measures of depression, anxiety, and psychosocial functioning. Outcomes were examined using linear mixed models with a random intercept for subject; and t-tests. Results: There were no statistically significant treatment type-by-time interactions for the main outcome measure but significant effects were seen for secondary measures (for example, time spent pulling per day for the past week). From baseline to week 6 there was a significant decrease in CGI severity for the silymarin group but not in the placebo group. Conclusions: This trial failed to show that silymarin/milk thistle was more effective than placebo on the main outcome measure, but silymarin/milk thistle did demonstrate significant improvements on select secondary outcome measures. These findings may shed light on important neurochemical targets worthy of future investigation.