Detecting comorbid Axis-II status among inpatients using the MMPI-2 Restructured Clinical Scales

This study examined the differential diagnostic utility of the MMPI-2 Restructured Clinical Scales (RCS) and Clinical Scales (CS) in detecting a complex multivariate clinical phenomenon: that is, comorbid Axis-II status in two matched samples of inpatients. Psychiatric inpatients diagnosed with either substance use disorder (n = 43) or major depression (n = 49) were matched on age, sex, and clinical setting, and compared with patients with the same Axis-I disorder and a comorbid personality disorder. Presence or absence of a comorbid personality disorder was chosen to provide a potent test of the differential diagnostic utility of the RCS versus CS when using a highly complex, multivariate criterion variable. Using hierarchical logistic regression analyses, the RCS consistently demonstrated higher diagnostic utility. Moreover, the RCS profiles were significantly more focused and more readily interpretable, relative to the CS profiles that were remarkably similar across disorders. These findings provide further support for the diagnostic and clinical utility of the RCS.