Inconsistent Responding in a Criminal Forensic Setting: An Evaluation of the VRIN-r and TRIN-r Scales of the MMPI-2-RF.

Criminal forensic evaluations are complicated by the risk that examinees will respond in an unreliable manner. Unreliable responding could occur due to lack of personal investment in the evaluation, severe mental illness, and low cognitive abilities. In this study, 31% of Minnesota Multiphasic Personality Inventory-2 Restructured Form (MMPI-2-RF; Ben-Porath & Tellegen, 2008/2011) profiles were invalid due to random or fixed-responding (T score ≥ 80 on the VRIN-r or TRIN-r scales) in a sample of pretrial criminal defendants evaluated in the context of treatment for competency restoration. Hierarchical regression models showed that symptom exaggeration variables, as measured by inconsistently reported psychiatric symptoms, contributed over and above education and intellectual functioning in their prediction of both random responding and fixed responding. Psychopathology variables, as measured by mood disturbance, better predicted fixed responding after controlling for estimates of cognitive abilities, but did not improve the prediction for random responding. These findings suggest that random responding and fixed responding are not only affected by education and intellectual functioning, but also by intentional exaggeration and aspects of psychopathology. Measures of intellectual functioning and effort and response style should be considered for administration in conjunction with self-report personality measures to rule out rival hypotheses of invalid profiles.

Evaluation of the Response Bias Scale and Improbable Failure Scale in assessing feigned cognitive impairment.

The present study evaluated the Response Bias scale (RBS), a symptom validity test embedded within the Minnesota Multiphasic Personality Inventory (MMPI)-2 Restructured Form (MMPI-2-RF) that assesses for feigned neurocognitive complaints, in a sample of pretrial incompetent to stand trial (IST) criminal defendants. Additionally, we examined the Improbable Failure (IF) scale, a performance validity test embedded within the Structured Interview of Reported Symptoms, Second Edition (SIRS-2), which similarly assesses for feigned cognitive impairment (FCI). Results indicated that both the RBS (area under the curve [AUC] = .76) and IF scale (AUC = .72) achieved moderate classification accuracy using the Test of Memory Malingering (TOMM) as the criterion. Further, the RBS and IF scale appeared to be most useful for screening out those defendants who presented as genuine (specificity = 99% and 88%, respectively), and less effective at classifying those defendants suspected of feigning according to the TOMM (sensitivity = 29% and 46%, respectively). In order to identify a significant proportion of IST defendants who may be feigning impairment, considerably lower cutoff scores than those recommended in each measure's manual were evaluated. An RBS T score of 63 (sensitivity = 86%; specificity = 37%), and IF scale raw score of 2 (sensitivity = 80%; specificity = 43%), was required to achieve ≥80% sensitivity; these alternate cutoff scores may therefore be useful when screening inpatient forensic psychiatric IST defendants. Further, the 2 scales effectively predicted TOMM classification in combination, although only the RBS significantly contributed to the model. Implications for the assessment of FCI in forensic psychiatric settings are discussed. (PsycINFO Database Record