Competence-related abilities and psychiatric symptoms: an analysis of the underlying structure and correlates of the MacCAT-CA and the BPRS.

The current study used confirmatory factor analysis to examine the factor structures of two instruments commonly used in the assessment of competency to stand trial--the MacArthur Competence Assessment Tool--Criminal Adjudication (MacCAT-CA) and the Brief Psychiatric Rating Scale (BPRS). Results revealed support for the three-subscale factor structure of the MacCAT-CA defined by the authors of the instrument; for a slightly altered three-factor structure defined by Zapf, Skeem, and Golding (2005, Psychological Assessment, 17, 433-445); and for the four symptom clusters of the BPRS as defined by Hedlund and Vieweg (1980, Journal of Operational Psychiatry, 11, 48-63). In addition, exploratory factor analysis of all 24 items of the BPRS revealed a five-factor structure. Correlations between psychiatric symptoms, symptom clusters, and competence-related abilities were also examined using the previously identified and the newly identified factor structures of the MacCAT-CA and the BPRS. Significant relations between symptoms and psycholegal abilities are discussed.