Trichotillomania or Hair Pulling Disorder is the compulsive behavior of pulling hair or pulling hair out. This often concerns areas of the head, but can include other areas of the body, such as from the eyebrows, eyelashes, arms, face and legs. The individual may pull their hair in a ritualized manner and some individuals with Hair Pulling Disorder may bite or eat the hair they have pulled. The hair pulling may cause significant distress and is often quite secretive. Areas that show hair damage or loss often cause embarrassment and shame. Individuals with Hair Pulling Disorder often struggle to come forward for treatment and may suffer for years with the condition. It is a commonly occurring condition that responds well to habit reversal training, an sub-therapeutic modality of Cognitive Behaviour (CBT) Therapy sometimes together with medication. The condition occurs slightly more commonly in women than men. Hair pulling behaviour may occur cyclically, where the individual may not pull for weeks or months (sometimes years) and then start pulling again. Stress, as well as boredom often precipitates episodes of hair pulling.

Hair Pulling Disorder used to be considered an impulse control disorder. Predominantly due to some individuals describing pulling urges, proceeded by a reduction in tension and feelings of pleasure. However this has not been widely reported and is no longer considered diagnostically significant. Hair Pulling Disorder is now considered an Obsessive Compulsive Spectrum Disorder (OCSD). The reason for including Hair Pulling Disorder as an OCSD is that it has many common features with OCD. Some of these features include the compulsive activity of hair pulling, similarities with the underlying neuro-cicrcuitry and that both conditions respond well to the same psychiatric treatments.