Development of a psychopathology rating scale for children with mental retardation.

A total of 583 children and adolescents with mental retardation were rated on a new psychometric instrument designed to screen for dual diagnosis (psychopathology in individuals with mental retardation). Two psychiatrists and two clinical psychologists judged the items to have face validity as expressions of psychopathology in children and adolescents with mental retardation. Cronbach's alpha coefficient was .91 for the total score and varied between .57 and .86 for 10 psychometric scales. Children and adolescents who had a dual diagnosis obtained total scores approximately 1 standard deviation higher than those who did not have a dual diagnosis. Each of 4 diagnostic groupings had test profiles in accordance with expectation. The results suggest that the instrument is particularly well suited for use in screening and for help in the analysis of the relationships between certain behavior problems and psychopathology.