Epilepsy and other central nervous system diseases in atypical autism: a case control study.

There is an increased but variable risk of epilepsy in autism spectrum disorders. The objective of this study is to compare the prevalence and types of epilepsy and other central nervous system (CNS) diseases in a clinical sample of 89 individuals diagnosed as children with atypical autism (AA) with 258 matched controls from the general population. Diagnoses were based on data from the nationwide Danish National Hospital Register. The average observation time was 32.9 years, and mean age at follow-up was 48.5 years. Of the 89 individuals with AA, 20 (22.5%) were registered with at least one epilepsy diagnosis against 11 (4.3%) in the comparison group (P < 0.0001; OR 6.5; 95% CI 3.0-14.2). Other CNS diseases occurred with low frequency in both groups, and no single CNS disease (except epilepsy) was significantly more frequent among patients with AA. Low intelligence was a risk factor for epilepsy in AA.