Epilepsy in young adults with autism: a prospective population-based follow-up study of 120 individuals diagnosed in childhood.

PURPOSE: Little is known about the long-term outcome of epilepsy in autism and the epilepsy characteristics of adults with autism. This prospective population-based study was conducted in an attempt to point out differences on a group basis between adults with autism with or without epilepsy, and to describe the occurrence, the seizure characteristics, and the outcome of epilepsy in autism.

METHODS: One hundred eight of 120 individuals with autism diagnosed in childhood and followed up prospectively for a period of 13-22 years were reevaluated at ages 17-40 years. As adults, the majority had mental retardation and autistic disorder or autistic-like condition. Interviews were performed with the caretakers of 42 of 43 individuals with a history of epilepsy, and their medical records were reviewed.

RESULTS: Adults with autism and mental retardation constituted a severely disabled group. On a group basis, both the cognitive level and the adaptive behavior level were lower in the epilepsy group than in the nonepilepsy group (p<0.05). In all, 38% had epilepsy. One third had epilepsy onset before age 2 years. Remission of epilepsy was seen in 16%. Partial seizures with or without secondarily generalized seizures were the dominating seizure type.

CONCLUSIONS: In a community sample of individuals with autism followed up from childhood through to adult age, one of three had epilepsy since childhood/adolescence. Severe mental retardation and autism are significantly associated with epilepsy, especially in female patients. Seizure frequency has a great impact on the individuals' lives. Specialist medical care is needed in this severely communication-disabled population.