Utility of the SIRS-2 in Distinguishing Genuine From Simulated Dissociative Identity Disorder

Individuals with trauma histories often elevate on validity scales and forensic interviews intended to detect symptom exaggeration or "faking bad." A widely used forensic interview designed to detect feigned psychiatric illness, the Structured Interview of Reported Symptoms (SIRS; Rogers, Bagby, & Dickens, 1992), overclassifies individuals with complex trauma, including patients with dissociative identity disorder (DID), as feigners (Brand, McNary, Loewenstein, Kolos, & Barr, 2006; Rogers, Payne, Correa, Gillard, & Ross, 2009). However, a new Trauma Index shows promise of being useful in accurately distinguishing feigned versus genuine individuals with severe trauma (Rogers et al., 2009). No studies have examined the performance of the new edition of the SIRS, the SIRS-2 (Rogers, Sewell, & Gillard, 2010), with severely traumatized or dissociative individuals. This study sought to determine the utility of the SIRS, the SIRS-2, and the Trauma Index in distinguishing genuine DID from simulated DID. A sample of 49 DID patients was compared to 77 well-coached DID simulators. The SIRS classification rules combined with the Trauma Index, as well as the Trauma Index alone, provided the best balance of sensitivity and specificity, with similar overall diagnostic power. The SIRS-2, either alone or combined with the Trauma Index, was not as sensitive as the SIRS or Trauma Index alone. However, the SIRS-2 demonstrated excellent specificity.