N-Acetyl Cysteine in Pathologic Skin Picking

The goal of the proposed study is to evaluate the comparative efficacy of N-acetyl cysteine to placebo in pathologic skin picking. Thirty subjects with pathologic skin picking will receive 12 weeks of double-blind treatment with N-acetyl cysteine or matching placebo. The hypothesis to be tested is that N-acetyl cysteine will be more effective than placebo in patients with pathologic skin picking. The proposed study will provide needed data on the treatment of an often disabling disorder that currently lacks a clearly effective treatment.

Pathologic skin picking involves repetitive, ritualistic, or impulsive picking of otherwise normal skin leading to tissue damage, personal distress, and impaired functioning. Although skin picking has been described in the medical literature for over one-hundred years, it remains a poorly understood psychiatric issue and often goes undiagnosed and untreated.

Picking behavior does not by itself suggest a psychiatric disorder. Pathology exists in the focus, duration and extent of the behavior, as well as the reasons for picking, associated emotions, and resulting problems. Patients with PSP report thoughts of picking or impulses to pick that are irresistible, intrusive and/or senseless. These thoughts, impulses, or behaviors also cause marked distress for patients and significantly interfere with other activities. Unlike normal picking behavior, the pathologic form of skin picking is recurrent and usually results in noticeable skin damage.

Thirty subjects with pathologic skin picking will receive 12 weeks of double-blind treatment with N-acetyl cysteine or matching placebo. The hypothesis to be tested is that N-acetyl cysteine will be more effective than placebo in patients with pathologic skin picking. The proposed study will provide needed data on the treatment of an often disabling disorder that currently lacks a clearly effective treatment.

• Pathologic Skin Picking
• Neurotic Excoriation
• Psychogenic Excoriation
• Dermatillomania

• Drug: N-Acetyl Cysteine
  Week 0 (Visit 1) - Week 3 (V2): 1200mg/day (600mg po qam and 600mg po qpm) Week 3 (V2) - Week 6 (V3): 2400mg/day (1200mg po qam and 1200mg po qpm) Week 6 (V4) - Week 12 (V5): 3000mg/day (1200mg po qam and 1800mg po qpm)
  Other Name: NAC
• Drug: Placebo
  Matching placebo capsules taken in same amount of pills as the active medication.
  Other Name: Sugar pill

• Active Comparator: N-Acetyl Cysteine
  N-Acetyl Cysteine - 600mg tablets by mouth (dosing 1200mg - 3000mg qd)
  Intervention: Drug: N-Acetyl Cysteine
• Placebo Comparator: Placebo
  Matching placebo taken daily
  Intervention: Drug: Placebo

• Arnold LM, Auchenbach MB, McElroy SL. Psychogenic excoriation. Clinical features, proposed diagnostic criteria, epidemiology and approaches to treatment. CNS Drugs. 2001;15(5):351-9. Review.
• Grant JE, Odlaug BL. Update on pathological skin picking. Curr Psychiatry Rep. 2009 Aug;11(4):283-8. Review.

Inclusion Criteria:

1. Men and women age 18-65;
2. Current diagnosis of pathologic skin picking as determined by criteria proposed by Arnold et al. (2001) for at least 6 months duration

Exclusion Criteria:

1. Unstable medical illness or clinically significant abnormalities on prestudy laboratory tests or physical examination;
2. History of seizures;
3. Myocardial infarction within 6 months;
4. Current pregnancy or lactation, or inadequate contraception in women of childbearing potential;
5. Need for medication other than NAC with possible psychotropic effects or unfavorable interactions with NAC;
6. Clinically significant suicidality (score or 3 or 4 on item 3 of the Hamilton Depression Rating Scale);
7. Lifetime history of DSM-IV bipolar disorder type I, dementia, or schizophrenia or any other DSM-IV psychotic disorder;
8. Current or recent (past 3 months) DSM-IV substance abuse or dependence;
9. Illegal substance use within 2 weeks of study initiation;
10. Initiation of pharmacotherapy, psychotherapy, or behavior therapy from a mental health professional within 3 months prior to study baseline for the treatment of pathologic skin picking;
11. Previous treatment with N-acetyl cysteine;
12. Treatment with investigational medication or depot neuroleptics within 3 months, with fluoxetine within 6 weeks, or with other psychotropics within 2 weeks prior to study baseline;
13. Asthma (given possible worsening of asthma due to NAC)