Also commonly known as TTM and "trich," trichotillomania(抜毛症)is an impulse control disorder characterized by the repeated urge to pull out one's hair. Classified by many clinicians as a habit behavior that falls into the same class as nail biting, TTM has no cure but can sometimes be managed with habit reversal training and pharmacotherapy(薬物療法). It is estimated that up to 5% of the world's population has TTM. In recent years, the number of reported TTM cases has increased.