N-Acetyl Cysteine in Pathologic Skin Picking

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.

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)