Detecting inmates malingering on the MMPI-2: An analogue investigation

In correctional settings, the appropriate provision of mental health services to inmates and the accurate identification of inmates' mental health needs are concerns. Psychological evaluations, however, are complicated by incentives that motivate inmates to exaggerate or fabricate symptoms of mental illness, which is commonly known as malingering. Therefore, effective means to evaluate malingering are important. The Minnesota Multiphasic Personality Inventory-2 (MMPI-2), which contains the Infrequency (F) scale, Infrequency-Back (Fb) scale, Infrequency-Psychopathology (Fp) scale, Gough’s Dissimulation (F – K) index, and Gough’s Dissimulation (Ds) scale for assessing malingering, is commonly used in correctional settings. However, only three published studies have investigated these validity indicators among inmates. Therefore, this dissertation sought to expand the knowledge of malingering by inmates on the MMPI-2. This study consisted of three groups of inmates. Forty-five male inmates from general population penitentiaries formed a simulating group and were asked to fake unspecified mental illness on the MMPI-2. A clinical comparison group of 65 male inmates from correctional psychiatric inpatient facilities who were suffering from mental illnesses were asked to honestly answer the MMPI-2. The third group consisted of 44 inmates from general population penitentiaries who were asked to complete the MMPI-2 under standard instructions and who formed the standard instructions group. Multivariate analysis of covariance (MANCOVA) procedures, with demographic differences between the groups held as covariates, indicated that the validity scales, with the exception of Fb, differentiated the simulating group from the standard instructions and clinical comparison groups. Logistic regression analyses identified the Fp and Ds scales as the most effective validity indicators in detecting malingering, and neither added incrementally to the predictive power of the other. These results support the use of the MMPI-2 and the Fp and Ds validity indicators for routine use in the assessment of malingering among inmates. As a result, correctional psychologists who use the MMPI-2 will be able to make more informed decisions in order to determine the presence or absence of genuine mental illness among inmates. Consequently, mental health services might be more appropriately disbursed. Findings and conclusions are discussed in light of limitations of the study.