Trichotillomania is a neglected psychiatric disorder with dermatologic expression that has only recently received research attention. On the basis of clinical data, trichotillomania appears to be far more common than previously believed. Like obsessive-compulsive disorder, the hair-pulling behavior is recognized as senseless and undesirable but is performed in response to several emotions and affects, such as increasing anxiety, or unconscious conflicts with resultant tension relief. The condition may be episodic but is usually chronic and difficult to treat. On the basis of possible medical and psychiatric complications, it is important that the diagnosis is exact and early. We describe the comorbidity and the phenomenology of trichotillomania, paying attention to the possible available treatments. (J Am Acad Dermatol 2002;46:807-21.) Learning objective: At the conclusion of this learning activity, participants should be familiar with clinical and histologic aspects of trichotillomania and should be able to cope with the risks of medical and psychiatric complications in these patients. Finally, participants will be able to easily interact with psychiatrists, when needed, to identify the most successful treatment.