Prevalence of psychopathology among mentally retarded adults.

The prevalence of psychopathological disorders was determined in a random, stratified sample of 165 adults, 110 males and 55 females, with mental retardation using the Psychopathology Instrument for Mentally Retarded Adults. Stratified variables included mental retardation level and living environment (institutional, family, independent). Results showed that 35.9% of the sample had at least one significant psychopathological disorder. Presence of pathology was related to level of retardation, but not to living environment, sex, or age. Difficulties associated with assessing pathology in persons with mental retardation are described.