Date of Award


Degree Type

Selective Evidence-Based Medicine Review

Degree Name

Master of Science in Health Sciences - Physician Assistant

Department Chair

John Cavenagh, PhD, PA-C


OBJECTIVE: The objective of this systematic review is to determine whether or not “Does N-acetylcysteine supplementation alleviate compulsive behavior in adults with impulse control disorders?”

STUDY DESIGN: Review of three English primary studies published between 2007 and 2009.

DATA SOURCES: One double-blind RCT, one open label trial followed by double-blind RCT, one case study. Studies were found using PubMed, Cochrane Systematic Reviews, OVID and Ebsco databases.

OUTCOMES MEASURED: Primary outcomes measured include severity of trichotillomania symptoms measured by MGHHPS, reduction of pathological gambling symptoms measured by YBOCS-PG, and reduction of compulsive grooming urges measured by patient reports.

RESULTS: In Grant, Odlaug et al.’s study, 44% of subjects assigned to NAC had a 50% or greater reduction on the MGH-HPS compared to 0% of those assigned to placebo. In Grant, Kim et al.’s study, 69.6% of subjects were responders on the PG-YBOCS at the end of the open-label NAC phase. At the end of the double-blind phase of the same trial, 83.3% of subjects assigned to NAC still
met responder criteria, compared to 28.6% of subjects assigned to placebo. In Odlaug et al.’s study, 3 out of 5 subjects treated with NAC reported cessation of compulsive behaviors within 3-5 months on 1800-2400 mg/day NAC.

CONCLUSIONS: Evidence is inconclusive regarding the use of NAC in the treatment of impulse control disorders. Its use appears promising, but long term research in larger populations is indicated. Tailored treatment may be warranted based on the severity and type of impulse control disorder, the presence of co-morbid psychiatric disease, and individual treatment responses. Further insight into long-term effects of NAC is indicated before its widespread use in the clinical setting.