Compulsions in adults with mental retardation: prevalence, phenomenology, and comorbidity with stereotypy and self-injury.

A variety of conceptual similarities between compulsions seen in individuals with obsessive compulsive disorder and stereotypy and self-injury seen in individuals with mental retardation led us to investigate the prevalence, phenomenology, and comorbidity of compulsions in adults with severe or profound mental retardation. We developed simple assessment screening instruments for stereotypy and self-injury and used Gedye's Compulsive Behavior Checklist and found acceptable levels of reliability, stability, and validity for each instrument. Prevalences were as follows: stereotypy: 60.9%; self-injury: 46.6%; and compulsion: 40%. The occurrence of compulsions was significantly positively associated with the occurrence of stereotypy, self-injury, and stereotypy plus self-injury.