Psychiatric disorders in adults diagnosed as children with atypical autism. A case control study.

The prevalence and types of psychiatric disorders were studied in a clinical sample of 89 individuals with atypical autism (AA) first seen as children, and 258 matched controls from the general population using data from the nationwide Danish Psychiatric Central Register. The average observation time was 36.9 years, and mean age at follow-up 45.3 years. A total of 61 persons with AA (68.5%) had been in contact with psychiatric hospitals during the follow-up period, compared with 10.9% in the comparison group. A whole range of significantly elevated psychiatric disorders was found, so AA is not seen to be associated with any specific mental disorder. Schizophrenia spectrum disorders were the most commonly associated psychiatric disorders, diagnosed at least one time in 34.8% of the AA cases. Our findings underscore that it is important for clinicians working in adult psychiatric services to be aware that AA and a wide range of psychiatric disorders often co-exist.