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

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. (PsycInfo Database Record (c) 2023 APA, all rights reserved).