Research on the MMPI

Today, I present two recent studies of the utility of the MMPI. First, Ambrose, Giarratano, McCue, Brand & Dalenberg (2023) published “Utility of the Minnesota Multiphasic Personality Inventory-2 in Differentiating Genuine from Feigned Dissociative Identity Disorder.” Psychological Trauma: Theory, Research, Practice, and Policy.  Here are the edited abstract and impact statements:

This study sought to determine the utility of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) in accurately distinguishing genuine dissociative identity disorder (DID) patients from coached and uncoached DID simulators. Method: DID patients (n = 34) who were diagnosed using the Structured Clinical Interview for DSM-IV—Dissociative Disorders were recruited from inpatient and outpatient settings. Coached (n = 25) and uncoached (n = 64) simulator groups were recruited from a Mid-Atlantic university. All participants completed the MMPI-2. MMPI-2 validity scales reliably distinguished simulators from DID patients with high sensitivity (0.95) and specificity (0.97). The scales showing greatest promise making the distinction were F minus K index, back infrequency scale, and superlative self-presentation. Simulators and genuine DID patients also differed in their pattern of symptoms. All results were calculated with White female DID patients and simulators only. Genuine DID patients can be differentiated from simulators. Simulators appear to overweight symptoms of paranoia and alienation relative to mood and somatic symptoms. Further research is needed to generalize these findings to male and non-White populations. 

The present study suggests that the Minnesota Multiphasic Personality Inventory-2 can successfully differentiate between White female patients with genuine dissociative identity disorder (DID) and individuals who are malingering the diagnosis. 

For anyone who deals with clients with DID symptoms, this research may be helpful in differential diagnosis. The next study looks at validity scales. Marquardt, Ferrier-Auerbach, Schumacher & Arbisi (2023) published “MMPI-2-RF validity scales add utility for predicting treatment engagement during partial psychiatric hospitalizations” in Psychological Assessment. The edited abstract and impact statements follow:

Partial psychiatric hospitalizations are resource-intensive clinical services designed to stabilize patients in the short term, prevent inpatient hospitalizations, and encourage long-term recovery. Typically, providers base their referral decisions on categorical diagnoses and subjective impressions of patient distress without closely considering the evidence for reporting biases. The present study followed veterans (n = 430) participating in partial psychiatric hospitalization services. We evaluated the extent to which clinical diagnoses at intake predicted treatment variables and changes in later mental health care utilization. Using hierarchical linear regressions with bootstrap confidence intervals, Minnesota Multiphasic Personality Inventory–2–Restructured Form content-based validity scales demonstrated incremental utility for predicting patient outcomes beyond intake diagnoses. Elevated Fp-r (“Infrequent Psychopathology Responses”) scores independently predicted an increased number of times arriving late for partial hospitalization programming, self-report of worse current functioning at intake, and a relative increase in mental health care encounters in the 12 months following discharge. Low K-r (“Adjustment Validity”) scores independently predicted self-report of worse current functioning at both intake and later discharge from partial hospitalization. Thus, indicators of severe psychopathology overreporting as well as the unlikely disavowal of emotional adjustment (i.e., high Fp-r, low K-r) predicted engagement with health care services and self-presentations of symptoms over and above the diagnostic impressions from referring providers. We discuss how indicators of content-based invalid responding on the Minnesota Multiphasic Personality Inventory–2–Restructured Form have real-world value for understanding patient behavior and shaping clinical interventions among vulnerable populations. 

The present study examined changes in functioning, individual experiences, and behaviors reported by veterans participating in partial psychiatric hospitalizations. MMPI-2-RF validity scales uniquely predicted treatment engagement and symptom endorsement, both during the partial hospitalizations and in the 12 months postdischarge. There is an added benefit in using measures of overreporting to understand patient behavior and outcomes in clinical settings. 

Although this study used veterans and, like the first one, needs replication with a more diverse sample of participants, it may be helpful to clinicians when partial hospitalization is necessary.