MMP…NGRI – Rare Insight Into the MMPI-2-RF Profiles of Evaluees Deemed Not Guilty By Reason of Insanity

MMP…NGRI – Rare Insight Into the MMPI-2-RF Profiles of Evaluees Deemed Not Guilty By Reason of Insanity

Article Title

Characterizing Contemporary Criminal Responsibility Evaluees Using the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF)


  • Jordan T. Hall; Department of Psychological Services, Kent State University, Kent, Ohio, USA
  • Jay S. Witherell; Michigan Center for Forensic Psychiatry, Saline, Michigan, USA
  • Yossef S. Ben-Porath; Michigan Center for Forensic Psychiatry, Saline, Michigan, USA


Few recent studies have examined the psychological characteristics of contemporary defendants evaluated for criminal responsibility. The current study sought to address this gap using the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF). We provide descriptive findings for a recently collected criminal responsibility evaluation sample, contrast the MMPI-2-RF scores of this sample with those of a sample of criminal responsibility evaluees tested approximately two decades earlier, and compare MMPI-2-RF scores of those opined by examiners to meet vs. not meet not guilty by reason of insanity (NGRI) criteria. Results of the comparisons of the two cohorts of evaluees tested 10–20 years apart suggest some differences in their overall psychological functioning. Within the updated sample, those opined to meet NGRI criteria showed less over-reporting, antisocial behaviors, internalizing dysfunction, and somatic complaints, and greater under-reporting than individuals in the non-NGRI group. Results are partly consistent with the broader literature, as well as prior work on use of the MMPI-2-RF in this context.


Assessment; MMPI; self-report; criminal responsibility

Summary of the Research

“Under U.S. law, criminal conviction normally requires proof of both participation in the criminal act, the actus reus, as well as unlawful intent or mens rea. Courts generally recognize that an individual can lack the capacity necessary to be held criminally responsible for an unlawful act. This principle underlies the insanity defense, an affirmative defense used when a defendant’s mental capacity renders them not criminally responsible for the act…Given the role of mental health in establishing a successful insanity defense, psychologists are frequently called upon to assist the trier of fact in making determinations about criminal responsibility…This involves gathering information about the defendant’s mental health and intervention history, their present psychological functioning, and review of records possibly relevant to ascertaining their mental state at the time of the offense (MSO)…Although psychological testing instruments do not directly address a defendant’s MSO, practitioners report regular use of them during evaluations of criminal responsibility…Among psychological tests used in MSO evaluations, Minnesota Multiphasic Personality Inventory (MMPI) instruments stand out as some of the most widely used and highly recommended tests…Despite their regular use, relatively few studies have examined MMPI scale scores in this context…” (p.348-349).

“Given the limited recent research on CREs [criminal responsibility evaluations] at large, we sought in the present study to extend the literature on this topic in two ways. First, we sought to compare the MMPI-2-RF scores of the current study sample of CREs with those generated some 10-20 years ago for the MMPI-2-RF forensic pretrial comparison group…Second, we sought to update to the broader literature on CREs by describing psychological characteristics of evaluees in a recently collected sample using a multi-scale inventory to delineate specific symptoms, thus providing an updated description of the types of psychopathology reported by individuals evaluated for criminal responsibility…Based on the literature reviewed, we hypothesized that individuals opined NGRI [not guilty by reason of insanity] would have higher scores on the MMPI-2-RF scales reflecting thought dysfunction and lower scores on scales reflecting externalizing problems. Additionally, we hypothesized that those opined NGRI would have lower scores on the over-reporting Validity Scales…” (p. 350-351).

“The full study sample was retrieved from an archival database and included 692 male and female defendants who were referred to the Center for Forensic Psychiatry (CFP), a state hospital in Michigan, for criminal responsibility evaluations between 2008 and 2013…Expert opinions on criminal responsibility were coded…This sample included individuals referred to undergo CREs at a court clinic in Ohio between 1989 and 2002. The full sample included 266 evaluees…With respect to protocol validity, average T-scores in both groups fell within the range of scores indicative of possible over-reporting of psychopathology…Rates of invalidity for over-reporting psychopathology were consistent across the two samples. Between samples, the study sample had higher rates of under-reporting, including reporting better psychological adjustment and number of uncommon virtues” (p. 351-356).

“Average substantive scale scores across both the study and comparison samples were generally within normal limits, with a few exceptions. Defendants in both samples produced mean T-score elevations on RC6, which is consistent with past research indicating that defendants assessed for criminal responsibility have high rates of psychotic dysfunction...Altogether, this pattern of results suggests that defendants in the contemporary study sample reported less overall psychopathology than the older sample described in Sellbom (2017), suggesting a potential decrease in psychopathology of evaluees over time…Finally, analyses comparing NGRI to non-NGRI defendants in our sample yielded results largely consistent with hypotheses. Overall, defendants opined NGRI in our sample evidenced less overall over-reporting on the MMPI-2-RF’s Validity Scales, which is consistent with the context of CREs where defendants may have an incentive to overreport to avoid conviction. This interpretation is bolstered by the evidence that evaluees in the non-NGRI group were more likely to produce invalid profiles due to overreporting psychopathology. Conversely, the NGRI group had higher scores on the MMPI-2-RF under-reporting scale…that is to say, defendants opined NGRI were more likely to present themselves in a positive light by indicating good psychological adjustment” (p.356).

“We found expected differences between the groups on scales reflecting externalizing dysfunction. Defendants opined NGRI reported less antisocial behavior, substance abuse, and aggressive, violent behaviors and loss of control…Counter to expectations, we found no differences between the NGRI and non-NGRI groups on scales reflecting thought dysfunction. With the exception of the mean score of the non-NGRI group on RC6, scores for both groups were within normal limits across all thought dysfunction indicators…[notably] defendants in both groups reported more thought dysfunction than average in the general population…Finally, we found differences between NGRI-opined and non-NGRI-opined evaluees on MMPI-2-RF internalizing, somatic, and interpersonal scales. Specifically, the NGRI-opined group reported less difficulties with emotional dysfunction, general sadness, and dissatisfaction with life, diminished positive emotionality, dysfunctional negative emotions…lack of confidence, and anger-proneness. Regarding somatic dysfunction, defendants opined NGRI reported less gastrointestinal complaints, head pain, and cognitive difficulties. Interpersonally, the non-NGRI evaluees reported less enjoyment of social events and more avoidance of social situations, as well as more shyness, social embarrassment, and discomfort around others…” (p. 356-357).

Translating Research into Practice

“Overall, results of the current study increment the literature regarding the psychological characteristics of NGRI acquittees, as well as provide useful comparison information for forensic examiners using the MMPI-2-RF in evaluations of criminal responsibility so they will know what types of scores to expect in this context. For example, evaluators observing a moderate elevation on RC6 can conclude that, although this level of persecutory ideation is atypical compared to the normative population, it would be considered fairly typical of test-takers in this context. Importantly, evaluators should not use results from the current study to inform use of MMPI-2-RF scales as predictors of criminal responsibility. The current study provides an updated psychological description of recently-collected CRE sample, which is necessary given the age of samples used [in] previously published studies examining this population. Although the MMPI-2-RF does not directly address MSO, the instrument can provide information regarding a defendant’s present psychological functioning, as well as well-validated indicators of potential malingering…” (p. 358).

Other Interesting Tidbits for Researchers and Clinicians

“These MMPI-2-RF Validity and Substantive Scales may be useful in the context of a CRE. The MMPI-2-RF provides information about a defendant’s level of psychosocial functioning as well as insight into the defendant’s test-taking approach (e.g., potential attempts to malinger or deny symptoms)…Select MMPI-2-RF Scales reflect constructs related to severe mental illness that are likely to be fairly chronic and that may be detectable even outside the acute episode surrounding the offense. Specifically, the MMPI-2-RF’s thought dysfunction scales (THD, RC6, RC8, and PSYC-r) assess maladaptive traits associated with psychosis…Similarly, RC9 measures excitable and irritable temperament associated with risk for mania…Finally, the MMPI-2-RF has several validity scales designed to detect response styles, information more directly applicable to the assessment of MSO. These scales provide information about the evaluee’s approach to the evaluation at hand that is also pertinent to a determination of malingering. Two previous studies (Sellbom et al., 2010) provide support for use of the MMPI-2-RF over-reporting scales, particularly the Infrequent Psychopathology (Fp-r), for detecting response styles in samples that included CREs” (p. 350).

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