N-acetylcysteine Shows Promise for Skin-Picking Disorder

July 1, 2016

Bret A. Moore, PsyD, ABPP Board-Certified Clinical Psychologist, San Antonio, TX Dr. Moore has disclosed that he has no relevant financial or other interests in any commercial companies pertaining to this educational activity.

Subject: (Grant J et al, JAMA Psychiatry, 2016;73:490–496)

Short Description: Excoriation, or what’s often referred to as skin-picking disorder (SPD), is a distressing and disfiguring behavior that affects up to 5% of people, occurring more commonly in women. Various lines of evidence imply that this compulsive behavior may be related to reduced levels of glutamate in the nucleus accumbens. N-acetylcysteine is an antioxidant that increases glutamate, and studies have shown that it is effective for excoriation’s sister disorder, trichotillomania (hair pulling). These data prompted investigators to try N-acetylcysteine in the treatment of SPD.

Over a 12-week period, 66 adult SPD patients from two Midwestern university-based clinics were randomized in a double-blind study to receive N-acetylcysteine (n=35) or placebo (n=31). The N-acetylcysteine group received 1,200 mg/day to start, increased to 2,400 mg/day by week three, and 3,000 mg/day by week six. An excoriation-specific version of the Yale-Brown Obsessive Compulsive Scale (NE-YBOCS) was used to assess picking symptoms over the three months. Researchers also used the Clinical Global Impression-Severity scale and other self-report, subjective measures.

The N-acetylcysteine seemed to work. Baseline NE-YBOCS scores dropped from 18.9 to 11.5 for the treatment group by the end of 12 weeks. During the same time period, the placebo scores shifted from 17.9 to 14.1. Subjective self-reports by the patients were also strong. Of the 53 patients who completed the study, 47% of the N-acetylcysteine group felt they were “much” or “very much” improved compared to only 19% of the placebo group. No significant adverse events were noted.

TCPR’s Take: The study was small, but given the benign side effect profile of N-acetylcysteine, it’s worth trying for patients with SPD.

General Psychiatry