In a prospective long-term outcome study of a representative sample of teenage-onset anorexia nervosa (AN), 51 individuals with AN, recruited after community screening, were contrasted with 51 matched comparison cases at a mean age of 24 years (10 years after AN onset). All 102 cases had been examined at age 16 and 21 years. At 24 years all probands were interviewed regarding mental and physical health, and overall outcome was assessed. Ten-year outcome of teenage-onset AN seemed to be relatively favourable in that half of all cases were free from eating disorder (ED) and other axis I disorder. There were no deaths. However, one in four in the AN group had a persisting ED, 3 of whom still had AN. Lifetime diagnoses of affective disorders and obsessive-compulsive disorder (OCD) were overrepresented in the AN group. Affective disorders coincided with the ED, and were not a problem after recovery from the ED. On the other hand, OCD, OCPD (obsessive-compulsive personality disorder), and/or autism spectrum disorder continued to characterise more than one-third of the AN cases. One in six of the AN group had persistent problems with social interaction and obsessive compulsive behaviours from childhood into early adult years. Half the AN group had a poor overall outcome. These were subjects with either persisting ED or lifelong problems with social interaction and obsessive compulsive behaviour.