The maladaptive trait model of personality has gained popularity in the assessment of personality pathology. The Minnesota Multiphasic Personality Inventory (MMPI-2-RF) is a widely used instrument to measure maladaptive traits, by means of the Personality Psychopathology 5 (PSY-5-r) scales. Polarity of these maladaptive trait measures—whether these traits are unipolar or bipolar maladaptive—has not been empirically established in the literature. In a clinical sample (N = 275), we investigated content polarity of these traits in relation to 25 psychological symptoms, measured by the Patient Description Form. Hierarchical regression analyses were applied to compare linear and curvilinear models and determine optimal fit. The results provided evidence for content unipolarity of all five traits, with small exceptions. We conclude that, in practice, the MMPI-2-RF PSY-5-r scales do not assess the PSY-5 theoretical model as expected, such that the higher the score on these scales the more it is likely impairing or impacting daily functioning. Conceptual and clinical implications are discussed.
