The prevalence and types of psychiatric disorders in 98 school-age children with mental retardation (MR) and active epilepsy were investigated in the Departments of Child and Adolescent Psychiatry and Pediatrics, University of Goteborg, Sweden. At least 1 psychiatric diagnosis was uncovered in 53 (59%) patients, and symptoms could not be classified because of profound MR in 30 (33%). Autistic disorder was diagnosed in 24 (27%), and autistic-like disorder in 10 (11%). ADHD was present in 11, and Angelman syndrome in 4. In those with autism the most common seizures were complex partial, absence, myoclonic, and tonic-clonic. A history of infantile spasms occurred in 12 (13%). Many of the psychiatric disorders had not previously been diagnosed despite parental concern. 
COMMENT. Autism or autistic-like disorder are common in children with mental retardation and epilepsy and are frequently undiagnosed. Neurologists and psychiatrists might work in closer collaboration for optimal management of these patients.