The association between psychiatric diagnoses and severe behavior problems in mental retardation.

To investigate the relationship between psychiatric disorders and severe behavior problems in mental retardation, statewide client databases from developmental disabilities services in California (N = 89,419) and New York (N = 45,683) were analyzed and juxtaposed. The study focussed on nine major DSM-III-R psychiatric categories (or their equivalents), and severe forms of aggressive behavior, property destruction, self-injurious behavior, and stereotyped behavior in individuals 45 years old and younger with mental retardation of all levels of severity. In California, 3.9% had at least one psychiatric diagnosis; in New York, 5.4%. The rate of specific psychiatric diagnoses was variable across states, suggesting local preferences in diagnostic practices. Severe behavior problems occurred in 22.1% in California and in 41.4% in New York. This difference in rates can be attributed in part to different recording criteria for behavior problems. With regard to the association between psychiatric diagnoses and problem behaviors the results were consistent across databases: No compelling correlations were found. This means that neither aggression, self-injury, destruction, nor stereotypies determine whether a person receives a psychiatric diagnosis or not.