excoriation disorder. A survey of college students found a rate of 4%. One study found that among non-disabled adults, 63% of individuals engaged in some form of skin picking and 5.4% engaged in serious skin picking. Lastly, a survey of dermatology patients found that 2% had excoriation disorder. In some patients, excoriation disorder begins with the onset of acne in adolescence, but the compulsion continues even after the acne has gone away. Skin conditions such as keratosis pilaris, psoriasis, and eczema can also provoke the behavior. In patients with acne, the grooming of the skin is disproportionate to the severity of the acne. Certain stressful events including marital conflicts, deaths of friends or family, and unwanted pregnancies have been linked to the onset of the condition. If excoriation disorder does not occur during adolescence another common age of onset is between the ages of 30 to 45. Additionally, many cases of excoriation disorder have been documented to begin in children under the age of 10. One small survey of patients with excoriation disorder found that 47.5% of them had an early onset of excoriation disorder that began before age 10. Traumatic childhood events may initiate the behavior. Excoriation disorder is statistically more common in females than in males. Excoriation disorder has a high rate of comorbidity with other psychiatric conditions, especially with mood and anxiety disorders . One survey of patients with excoriation disorder found that 56.7% also had a DSM-IV Axis-I disorder and 38% had substance use problems. Studies have shown the following rates of psychiatric conditions found in patients with excoriation disorder: trichotillomania (38.3%), substance use disorder (38%), major depressive disorder (approximately 31.7% to 58.1%), anxiety disorders (approximately 23% to 56%), obsessive-compulsive disorder (approximately 16.7% to 68%), and body dysmorphic disorder (approximately 26.8% to 44.9%). There are also higher rates of excoriation disorder in patients in psychiatric facilities; a study of adolescent psychiatric inpatients found that excoriation disorder was present in 11.8% of patients. It is also present at high rates with some other conditions: 44.9% of patients with body dysmorphic disorder also have excoriation disorder; 8.9% of patients with OCD have excoriation disorder; and 8.3% of patients with trichotillomania have excoriation disorder. Skin picking is also common in those with certain developmental disabilities; for example, Prader–Willi syndrome and Smith–Magenis syndrome. Studies have shown that 85% of people with Prader–Willi syndrome also engage in skin-picking. Children with developmental