Among adults, Trichotillomania appears to be much more common among females than among males. No systematic data are available on the prevalence of Trichotillomania. Although Trichotillomania was previously thought to be an uncommon condition, it is now believed to occur more frequently. However, many individuals who present with chronic Trhichtillomania in adulthood report onset in early childhood. The age at onset is usually before young adulthood, with peaks at around ages 5-8 years and age 13 years.
Some individuals have continuous symptoms for decades.
For others, the disorder may come and go for weeks, months, or years at a time. Sites of hair pulling may vary over time. The repetitive hair pulling in Trichotillomania must be distinguished from a compulsion, as in Obsessive-Compulsive Disorder . In Obsessive-Compulsive Disorder, the repetitive behaviors are performed in response to an obsession, or according to rules that must be applied rigidly. An additional diagnosis of Stereotypic Movement Disorder is not made if the repetitive behavior is limited to hair pulling.