Below, is a nice summary regarding this exciting avenue of treatment by principal investigator and Trichotillomania Learning Center (TLC) Scientific Advisory Board member, Dr. Jon Grant:
N-Acetyl Cysteine (NAC), a dietary supplement and amino acid that affects glutamate levels in the brain, has been studied in the treatment of a number of conditions across medicine and psychiatry. In recent years, NAC has been thought to have the potential to improve symptoms of Trichotillomania (hair pulling). As no medication or other substance to date has shown effectiveness in the treatment of TTM, this finding is one of promise and one that warrants consideration and further investigation.
A preliminary (controlled, randomized) study of 50 individuals with Trichotillomania concluded that 56% of individuals reported a significant reduction of symptoms after 9-12 weeks of treatment (Grant, JE, et al, 2009). This is encouraging. Of course, it must be kept in mind that this was a small study (50 individuals makes it difficult to generalize results). It is also important to note that 44% of individuals did not report significant improvement of symptoms; thus, if it is effective, it is not likely to be effective for everyone who struggles with hair pulling behavior.
This being said, NAC has shown promise in becoming an evidence-based treatment for TTM. Current evidence-based treatment for TTM is a specific cognitive behavioral therapy approach [namely, habit reversal training (HRT) or Comprehensive Behavioral treatment (ComB)].
I see many individuals with TTM in my practice. I often discuss NAC as an option to supplement treatment, particularly for those who struggle with behavior therapy or for those who have a co-occurring autism spectrum disorder or other diagnosis that may challenge the successful treatment of hair pulling.
Glutamate may play an important role in, not only TTM, but also other body-focused repetitive behaviors (BFRBs) such as skin picking, nail biting, cheek biting, and others. It will be an important area of investigation in future treatment trials and an option to consider in treatment planning.
*Grant JE, Oldaug BL, Kim SW. 2009. A double-blind, placebo-controlled trial of a glutamate modulating agent, N-acetyl cysteine, in the treatment of trichotillomania. Arch Gen Psychiatry 66(7): 756-763