Incremental validity of the MMPI-2 PSY-5 scales in assessing self-reported personality disorder criteria

The Minnesota Multiphasic Personality Inventory-2 (MMPI-2) Personality Psychopathology-Five (PSY-5) scales were developed to measure abnormal personality symptomatology. The present study examines the incremental validity of the PSY-5 scales beyond the clinical and content scales in assessing criteria associated with personality disorders. The current sample includes 240 male and 407 female clients from private practice settings who completed the MMPI-2 and the Multiaxial Diagnostic Inventory (MDI), a self-report checklist of Diagnostic and Statistical Manual of Mental Disorders (3rd ed., revised) symptoms. Six of the MDI personality disorder scales, conceptually related to the PSY-5 scales, are used as criteria. Hierarchical regression analyses determine the incremental validity of each PSY-5 scale. In most analyses, PSY-5 scales add a significant increment of variance to the clinical and content scales. Implications of the results are discussed.     

Delusions and decision-making style: use of the Need for Closure Scale

Clinicians and researchers have suggested that rapidity in belief formation, due to having a high 'need for closure' (NFC), may contribute to the acceptance of delusional explanations. The aim of the study is to determine whether NFC has such a direct link with delusions. A secondary aim is to examine if NFC is related to the delusion-associated reasoning process of 'jumping to conclusions'. One hundred and eighty-seven patients with psychosis, recruited for a treatment trial of psychological therapy (the PRP trial), completed the Need for Closure Scale (NFCS), symptom measures, and probabilistic reasoning tasks. The NFCS was considered in terms of its two dimensions: a desire for simple structure and a preference for quick, decisive answers. The individuals with psychosis reported being poor at making quick, decisive answers but required a greater need for simple structure. NFC was associated with levels of anxiety and depression. There were weak links between NFC and both positive and negative symptoms of psychosis, but these were explained by differences in affect. NFCS scores were unrelated to jumping to conclusions. Contrary to the argument that NFC is directly linked to delusions, individuals with delusions actually perceive themselves as indecisive. There was no evidence that NFC-at least as assessed by the NFCS-could be a proximal cause of delusions. Any potential effect on psychotic symptom presentation is indirect, mediated through affect. The use of the NFCS on its own in the study of psychotic symptoms cannot be recommended.