Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Johnny L. Matson


Sixty-five mildly to moderately mentally retarded adult patients from institutional and community placements in Louisiana and Texas and with a diagnosis of schizophrenia, depression, or no psychopathology were recruited. The primary goal of the study was to establish the validity of the schizophrenia subscale of the PIMRA for diagnosing schizophrenia among mentally retarded individuals. The same methods utilized to determine the validity of the schizophrenia subscale were also used to replicate the validation of the depression subscale of the PIMRA. In addition, the extent to which other PIMRA subscale scores aid in diagnosis was investigated. Assessment measures included the informant version of the PIMRA, DSM-III-R checklists for schizophrenia and depression, and a drug response rating. Univariate and multivariate analyses were conducted as well as interrater reliability on all measures. Results provided some support for the validity of the schizophrenia subscale of the PIMRA. Support was more strongly indicated, however, for the affective disorder subscale of this measure. Combinations of subscales improved prediction of group membership. Issues such as the impact of reliability and small sample size on results were discussed. Implications of the research as well as directions for future research were presented.