N-Acetylcysteine for Anxiety and Skin Picking
N-acetylcysteine (NAC) is effective for skin-picking disorder at doses of 1200-3000 mg/day, with approximately 47% of patients achieving significant improvement, but there is insufficient evidence to recommend NAC specifically for anxiety disorders. 1
Evidence for Skin-Picking Disorder
Primary Treatment Recommendation
NAC should be initiated at 1200 mg/day and titrated up to 3000 mg/day over 12 weeks for patients with excoriation (skin-picking) disorder. 1 This recommendation is based on the highest quality randomized controlled trial available:
- A double-blind RCT of 66 adults with skin-picking disorder demonstrated that NAC treatment resulted in significant reductions on the modified Yale-Brown Obsessive Compulsive Scale (NE-YBOCS) compared to placebo (P = 0.048) 1
- At study endpoint, 47% of NAC-treated patients were "much or very much improved" compared to only 19% receiving placebo (P = 0.03) 1
- The treatment was well-tolerated with minimal adverse effects 1
Mechanism of Action
NAC appears to work by restoring extracellular glutamate concentration in the nucleus accumbens, modulating the glutaminergic pathway that is dysregulated in compulsive behaviors 1, 2
Supporting Evidence
- A systematic review found favorable evidence for NAC in treating skin-picking disorder, trichotillomania, and nail biting 2
- Case series from clinical practice demonstrate successful treatment of skin-picking with NAC, with good tolerability 3
- In Prader-Willi syndrome patients with severe skin-picking, NAC at 450-1200 mg/day resulted in improvement in all 35 treated individuals, with 71% achieving complete resolution 4
Evidence for Anxiety Disorders
There is currently no high-quality evidence supporting NAC use specifically for anxiety disorders. 2 The systematic review of NAC in psychiatric disorders found that anxiety has only "preliminary evidence and requires larger confirmatory studies" 2
Practical Implementation
Dosing Strategy
- Start with 1200 mg/day (600 mg twice daily) and increase to 2400-3000 mg/day as tolerated over 2-4 weeks 1
- Treatment duration should be at least 12 weeks to assess efficacy 1
- NAC can be administered orally and is generally safe with minimal adverse effects 5
Safety Profile
- Adverse effects are uncommon, with nausea/vomiting <5%, skin rash <5%, and bronchospasm 1-2% 5
- NAC is generally safe and well-tolerated across psychiatric populations 2
- The main limitation is the sulfuric odor, which may affect adherence 6
Clinical Monitoring
- Assess skin-picking severity at baseline using standardized measures (NE-YBOCS or Clinical Global Impression scales) 1
- Re-evaluate at 4,8, and 12 weeks to determine treatment response 1
- Document number and size of active lesions if present 4
Important Caveats
Behavioral therapy remains the first-line treatment for skin-picking disorder, with NAC serving as an adjunctive or alternative pharmacological option. 7 The evidence suggests NAC may be particularly useful when behavioral interventions are insufficient or unavailable 7
For anxiety disorders specifically, standard evidence-based treatments (SSRIs, SNRIs, cognitive-behavioral therapy) should be prioritized over NAC given the lack of robust supporting data 2