The schizophrenia-organicity (SC-O) and psychiatric-organic (P-O) MMPI scales: a review

Abstract

Reviewed the research on the MMPI Schizophrenia-Organicity (Sc-O) and Psychiatric-Organic (P-O) Scales, measures developed to separate brain-damaged patients from schizophrenics and from functional psychiatric patients as a whole. Over 10 cross-validations, the average Sc-O scale hit rate has been 69%, which suggests that it is a better differentiator of brain-damaged from schizophrenic males than most popular ability-based organicity tests. Hit rates for five studies that contrasted organic and psychiatric patients on the P-O scale also averaged 69%. The scales appear to be useful in both medical and psychiatric hospitals, but their validities in female samples are not well established. A system for making diagnostic decisions from ability and personality measures in combination is described, and evidence is cited that it improves on the hit rates achieved by either type of test alone.