Editing Trichotillomania (section)

==Epidemiology==
Although no [[Population study|broad-based population]] [[epidemiology|epidemiologic studies]] had been conducted as of 2009, the lifetime [[prevalence]] of trichotillomania is estimated to be between 0.6% and 4.0% of the overall population.<ref name="Huynh2013"/> With a 1% prevalence rate, 2.5 million people in the U.S. may have trichotillomania at some time during their lifetimes.<ref name="Diefenbach2">{{cite journal | vauthors = Diefenbach GJ, Reitman D, Williamson DA | title = Trichotillomania: a challenge to research and practice | journal = Clinical Psychology Review | volume = 20 | issue = 3 | pages = 289–309 | date = April 2000 | pmid = 10779896 | doi = 10.1016/S0272-7358(98)00083-X }}</ref>

Trichotillomania is diagnosed in all age groups; onset is more common during preadolescence and young adulthood, with mean age of onset between 9 and 13 years of age,<ref name="Sah">{{cite journal | vauthors = Sah DE, Koo J, Price VH | title = Trichotillomania | journal = Dermatologic Therapy | volume = 21 | issue = 1 | pages = 13–21 | date = January 2008 | pmid = 18318881 | doi = 10.1111/j.1529-8019.2008.00165.x | doi-access = free }}</ref> and a notable peak at 12–13.<ref name="Chamberlain"/> Among preschool children the genders are equally represented; there appears to be a female predominance among preadolescents to young adults, with between 70% and 93% of patients being female.<ref name="Sah"/> Among adults, females typically outnumber males by 3 to 1.<ref name="Chamberlain"/>

"Automatic" pulling occurs in approximately three-quarters of adult patients with trichotillomania.<ref name="Sah"/>