MMPI criteria for diagnosing schizophrenia

An attempt was made to find a combination of MMPI scale relationships which were highly discriminating of schizophrenia. Through the use of a standardized structured interview and a diagnostic system for schizophrenia based on the use of discriminant function analysis with nonpathognomonic symptom combinations, a reliable and valid system was used to establish the criterion diagnosis. Approximately 72% of patients reliably diagnosed as schizophrenics were detected on the MMPI via a set of standard criteria (T score on Sc greater than or equal to 80 less than or equal to 100; total raw score on Sc consisted of no more than 35% K items; T score on F greater than or equal to 75 less than or equal to 95; T score on Pt less than or equal to Sc). Only 5.5% of nonschizophrenics obtained all these standard criteria on the MMPI. The assets and liabilities of these MMPI criteria to diagnose schizophrenia are discussed.