Progress in the treatment of trichotillomania

Trichotillomania is a curious affliction characterized by the unsuppressed impulse to pluck hairs out of one's head (or body). One of my best friends experienced this phenomenon when he was undergoing the stress of a divorce. A well-adjusted, intelligent, educated, stable man in every regard, he began to pluck hairs from his head, which he would then casually examine, and then either discard, eat (!), or set fire to with a cigarette lighter. With the resolution of his family problems the syndrome spontaneously subsided.

Today the BBC reports that the drug N-acetylcysteine (NAC) has shown some efficacy in suppressing trichotillomania:

After 12 weeks, patients taking the active medication had significantly greater reductions in hair-pulling symptoms than those taking placebo.

Overall, 56% of patients were considered to be "much or very much improved" with N-acetylcysteine use compared with 16% taking placebo...

The magnitude of improvement seen in patients taking the amino acid pills was greater than that reported with other medications and was similar to that reported for cognitive behaviour therapy alone or combined with medication, such as antidepressants.

N-acetylcysteine is a curious drug to apply to this disorder, which has previously been (largely ineffectively) treated with antidepressant and antipsychotic formulations, because NAC is best known as a aerosolized mucolytic used to loosen the inspissated bronchial secretions of patients with cystic fibrosis. It does have antioxidant properties, though why that should alleviate an impulse-control disorder is beyond me.