Use of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) may help identify early psychosis at least as well as the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders IV Text Revision (SCID). In addition, the use of a combination of the MMPI-2 and the SCID has demonstrated incremental validity compared with the use of the SCID alone. The study was conducted among first-admission patients at the Psychiatric Centre Hvidovre—a department of the University Hospital of Copenhagen, Denmark. Results of the analysis were published in the journal Psychiatry Research.
The investigators sought to assess the use of the MMPI-2 as a potential means of improving on the diagnostic efficacy of the SCID. A total of 76 first-admission psychiatric patients were assigned DSM-IV consensus diagnoses by two experienced psychiatrists utilizing all available information and then dichotomized into 1 of 2 groups: (1) the nonaffective psychosis group and (2) the other mental illness group. The SCID and the MMPI-2 were administered to all patients. The diagnostic performance of the MMPI-2 was compared with that of the SCID in order to evaluate both incremental validity and diagnostic accuracy.
The MMPI-2 scales 8 (Schizophrenia) and BIZ (Bizarre Mentations) demonstrated the ability to correctly identify 58% and 56%, respectively, of patients with nonaffective psychosis. Moreover, the Goldberg Index had an overall correct classification rate of 70%, but identified only 49% of the psychosis group. In contrast, although the SCID had a correct classification rate of 66%, it correctly identified only 25% of patients in the nonaffective psychosis group. Furthermore, use of 3 MMPI-2 scales combined with the SCID was associated with an overall correct classification rate of 73% and identified 66% of the patients with nonaffective psychoses.
The investigators concluded that the findings from this study imply that the use of the SCID to diagnose psychosis in early identification samples is insufficient when utilized alone. When the MMPI-2 is used along with the SCID, this adds an incremental validity and increases the accuracy for diagnosing psychosis. Further studies are warranted, in order to cross-validate these results.
Psychiatry Res. 2019;279:71-76. doi:10.1016/j.psychres.2019.07.010