Distinguishing clinical and simulated dissociative identity disorder using the Miller Forensic Assessment of Symptoms Test.

Abstract

Background: Individuals with dissociative identity disorder (DID) experience severe and broad-ranging symptoms which can be associated with elevations on measures designed to detect feigning and/or malingering. Research is needed to determine how to distinguish genuine DID from simulated DID on assessment measures and validity scales. Objective: This study examined whether the Miller Forensic Assessment of Symptoms Test (M-FAST), a screening measure of malingering, could differentiate between individuals with DID and DID simulators. Method: Thirty-five individuals with clinical, validated DID were compared to 88 individuals attempting to simulate DID on the M-FAST. A MANCOVA compared the two groups on total M-FAST score and subscales. Univariate ANCOVA's examined differences between the groups. A series of logistic regressions were conducted to determine whether group status predicted the classification of malingering. Utility statistics evaluated how well the M-FAST discerned clinical and simulated DID.Results: The M-FAST correctly classified 82.9% of individuals with DID as not malingering when using the suggested cut-off score of six. However, utilizing a cut-off score of seven correctly classified 93.6% of all participants and maintained adequate sensitivity (.96) but demonstrated increased specificity (.89). Conclusions: The M-FAST shows promise in distinguishing genuine DID when the cut-off score is increased to seven. This study adds to the growing body of literature identifying tests that can adequately distinguish clinical from simulated DID. Clinical Impact StatementWhile the M-FAST performed well at classifying malingering among those attempting to simulate dissociative identity disorder (DID), it correctly classified approximately only 83% of individuals diagnosed with DID as not malingering, indicating that a cut-off score of 6 on the M-FAST performs poorly with this population. However, by increasing the cut-off score to 7, the M-FAST improved substantially such that most individuals with DID were classified correctly, while still maintaining high sensitivity. These results suggest that a cut-off score of 7 may be indicated for individuals with DID.

Distinguishing genuine from simulated dissociative identity disorder using the Morel Emotional Numbing Test.

“…To improve specificity in embedded measures, researchers will often propose population-specific cutoffs (e.g., Erdodi et al, 2014; Finley, Cerny, et al, 2024; Tse et al, 2023). However, few studies have proposed cutoffs for DID (Barth et al, 2023). Some cutoffs have been adjusted for individuals with posttraumatic stress disorder (PTSD), but thus far, these have not worked well for individuals with DID, presumably because they have different symptomology and comorbidities that may influence the severity of symptom endorsement (e.g., Brand et al, 2006; Rogers et al, 2009).…”

“…Fewer studies have exclusively focused on DID populations. Although various types of validity tests exist, researchers in these studies have predominately investigated content-based measures of symptom overreporting (e.g., Ambrose et al, 2023;Barth et al, 2023;Brand & Chasson, 2015;Brand et al, 2006Brand et al, , 2014Brand et al, , 2019Brand et al, , 2021.…”

“…The few studies examining freestanding validity tests in individuals with DID have shown promising results. For example, Barth et al (2023) found that a revised cutoff from the Miller Forensic Assessment of Symptoms Test (M-FAST; Miller, 2000), a freestanding SVT, demonstrated high specificity (.89) and sensitivity (.96) in individuals with DID. Another freestanding test, the Test of Memory Malingering (TOMM; Tombaugh, 1997), has also shown efficacy in individuals with dissociative disorders and symptoms (Brand et al, 2019;Simotas, 2000).…”

The forensic assessment of dissociation: Distinguishing real from the unreal

“…Barth et al. (2023) examined if the M‐FAST could differentiate between individuals with DID and DID simulators. In their study, they compared 35 individuals with validated DID with 88 individuals attempting to simulate DID on the M‐FAST.…”

“…Scores of 6 or higher suggest possible malingering with further assessment using more thorough instruments recommended (Miller, 2000). Barth et al (2023) examined if the M-FAST could differentiate between individuals with DID and DID simulators. In their study, they compared 35 individuals with validated DID with 88 individuals attempting to simulate DID on the M-FAST.…”