Autism in mental retardation

There is a close relationship between autism and mental retardation, About three-quarters of people with autism also suffer from mental retardation of varying degree. Although most cases of autism are idiopathic in nature, ap proximately 10-25% are associated with known medical conditions, most of wh ich involve mental retardation syndromes. Autism occurs more commonly with some conditions (such as tuberous sclerosis and fragile X syndrome) than wi th others (such as Down's syndrome and cerebral palsy). The present review examines recent research focusing on the comorbidity of autism with mental retardation. Association of autism with certain mental retardation syndrome s is discussed, and the need for further research is emphasized. Curr Opin Psychiatry 13:481-484. (C) 2000 Lippincott Williams & Wilkins.