Structured Inventory Of Malingered Symptomatology Research Articles

Psychometric validation of the Italian Self-Report Symptoms inventory (SRSI): Factor structure, construct validity, and diagnostic accuracy

The Self-Report Symptom Inventory (SRSI) is a novel tool designed to detect symptom overreporting and other forms of noncredible responding. Unlike existing scales, the SRSI includes genuine and pseudosymptoms scales covering cognitive, affective, motor, pain, and post-traumatic stress disorder domains. The present study aims to investigate the psychometric properties of the Italian Version of the SRSI (SRSI-It), in particular, its factor structure, reliability, convergent and discriminant validity, and diagnostic accuracy. Data from 1180 healthy participants showed a hierarchical structure with higher-order constructs for genuine symptoms and pseudosymptoms, each comprising five subscales. The SRSI-It showed a strong convergent validity with the Structured Inventory of Malingered Symptomatology and discriminant validity through low correlations with the Psychopathic Personality Inventory-Revised. Receiver operating characteristic analysis determined cut scores of 6 (95% specificity) and 9 (98% specificity) for pseudosymptoms, with a Ratio Index score of 0.289 (82% specificity). In summary, the SRSI-It appears to be a promising tool for identifying symptom exaggeration in clinical and forensic contexts, ultimately enhancing the quality and reliability of evaluations in these contexts.

Results of Symptom Validity Testing in Portuguese Prison Inmates: The Influence of Educational Level, Age, and Conviction Status

Current guidelines for psychological assessment recommend the use of multiple validity measures in an evaluation protocol, particularly in forensic settings. As such, self-report instruments which detect distorted symptom reporting have become essential. We studied a pooled sample of 240 male inmates with the Self-Report Symptom Inventory (SRSI), the Structured Inventory of Malingered Symptomatology (SIMS), and the Symptom Validity Scale–Version 2 (EVS-2). Concurrent validity was analyzed via correlations between all three symptom validity tests (SVTs), revealing strong associations (rho ranging from .72 to .79), and ROC analyses yielded areas under the curve (AUC) values over .9 for every model. Base rates of SVT failure ranged from 7.9 to 13.3% using the most conservative cutoff scores, although true and false positive rates were not established. Education was shown to have a statistically significant effect on the mean results of the three SVTs (rho ranging from − 162 to − 283), associating lower educational levels with more bogus symptom endorsement. The influence of age and conviction status (pre-trial vs. post-trial) on the SIMS results was statistically significant as well (rho estimates of .171 and − 232). With data showing robust construct validity and excellent predictive accuracy, the instruments were shown to be adequate for use in the Portuguese prison context, but further research is required, in particular using forensic inpatients and clinical populations, and including systematic data on the presence of mental disorders.

EMG measured reaction time as a predictor of invalid symptom report in psychosomatic patients

Background: Symptom validity tests (SVTs) and performance validity tests (PVTs) are important tools in sociomedical assessments, especially in the psychosomatic context where diagnoses mainly depend on clinical observation and self-report measures. This study examined the relationship between reaction times (RTs) and scores on the Structured Inventory of Malingered Symptomatology (SIMS). It was proposed that slower RTs and larger standard deviations of reaction times (RTSDs) would be observed in participants who scored above the SIMS cut-off (>16). Methods: Direct surface electromyography (EMG) was used to capture RTs during a computer-based RT test in 152 inpatients from a psychosomatic rehabilitation clinic in Germany. Correlation analyses and Mann-Whitney U were used to examine the relationship between RTs and SIMS scores and to assess the potential impact of covariates such as demographics, medical history, and vocational challenges on RTs. Therefore, dichotomized groups based on each potential covariate were compared. Results: Significantly longer RTs and larger RTSDs were found in participants who scored above the SIMS cut-off. Current treatment with psychopharmacological medication, diagnosis of depression, and age had no significant influence on the RT measures. However, work-related problems had a significant impact on RTSDs. Conclusion: There was a significant relationship between longer and more inconsistent RTs and indicators of exaggerated or feigned symptom report on the SIMS in psychosomatic rehabilitation inpatients. Findings from this study provide a basis for future research developing a new RT-based PVT.

A - 186 Performance Characteristics of the Structured Inventory of Malingered Symptomatology in a Diverse Community Sample of Social Security Disability Applicants.

Analyze performance characteristics of the Structured Inventory of Malingered Symptomatology (SIMS) in a diverse community sample of SSDI applicants. 532 adult SSDI applicants providing research consent were administered the SIMS in conjunction with standard psychodiagnostic, intellectual, and neuropsychological assessments performed in a private practice setting. A broad range of ages and referring diagnoses are represented. Mean age was 42years (SD = 13), with 56% female and 44% male. Based on the nature of the examination, WAIS (n = 47), WMS (n = 60), and Trail Making Test (n = 50) data were obtained, along with performance validity tests (PVTs) including Reliable Digit Span (n = 182), Dot Counting Test (n = 18), and Test of Memory Malingering (n = 70). No meaningful age or gender differences emerged across SIMS scores. The mean SIMS Total Score within this population is 22.9 (SD = 10.1). This compares to a suggested manual cutting score of 14-16 for detection of likely noncredible symptom reporting. 69% of this population produced SIMS Total Scores at or above 16, with 45% of the sample scoring 21 or above. Established studies indicate a roughly 46% base rate of symptom invalidity in SSDI applicants. Standard SIMS cutoff scores when used with this population are likely to overestimate invalidity. Upward adjustment to 21 may be indicated for the SIMS Total Score when attempting to capture a portion of the SSDI population more likely to demonstrate symptom invalidity. Individual subscale performances and correlations with concurrently administered Wechsler scales and PVTs are reported, along with data limitations and additional areas of suggested research.

Symptom validity indices in the Posttraumatic Stress Disorder Checklist for DSM-5.

The use of symptom validity tests (SVTs) is standard practice in psychodiagnostic assessments. Embedded measures are indices within self-report measures. To date, no embedded SVTs have been identified in the Posttraumatic Stress Disorder Checklist for DSM-5 (PCL-5). This research aimed to develop and validate PCL-5 SVTs in two samples of veterans. Participants completed one of two prospective research studies that included cognitive and psychological tests. Participants in Study 1 were veterans (N = 464) who served following the September 11, 2001, terrorist attacks; participants in Study 2 were veterans or service members (N = 338) who had been deployed to Iraq and/or Afghanistan. Both studies included the PCL-5 and the Structured Inventory of Malingered Symptomatology (SIMS), the latter of which served as the criterion for identifying PCL-5 SVTs. For Study 1, two separate SVTs were developed: the PCL-5 Symptom Severity scale (PSS), based on the PCL-5 total score, and the PCL-5 Rare Items scale (PRI), based on PCL-5 items infrequently endorsed at the highest item ratings. At the most conservative SIMS cutoff score, the PSS achieved excellent discrimination for both the Study 1, AUC = .840, and Study 2 samples, AUC = .858, with specific cutoff scores of ≥ 51 and ≥ 56 maximizing sensitivity while maintaining a specificity of .90. The PRI achieved good discrimination, AUCs = .760 and.726, respectively, with a cutoff score of 2 or higher indicated by both studies. The results of these two studies provide provisional support for these two embedded SVTs in the PCL-5.

Discriminant validity of the Structured Inventory of Malingered Symptomatology (SIMS) under conditions of simulating symptoms

Background/Aim. The Structured Inventory of Malingered Symptomatology (SIMS) is a self-report measure to be used with adults, which may be utilized to assess the potential malingering of psychosis, neurologic impairment, amnesia, low intelligence, or affective disorder. The aim of the study was to examine the discriminant validity of SIMS under conditions of simulating symptoms of neurological and memory disorders, in response to a hypothetical situation, after watching a recording of an actual car accident in which a motorcycle rider sustained head injuries. Methods. The study involved 94 students (35 men and 59 women) from the University of Criminal Investigation and Police Studies in Belgrade and the Faculty of Medicine ? Special Education and Rehabilitation in Novi Sad, aged 20?26 [arithmetic mean = 20.69; standard deviation (SD) = 0.80], divided into two groups (n = 4 7), malingerer and control. The malingerer group was instructed to identify with the motorcycle rider hit by the car and malinger symptoms related to neurological difficulties and amnesia in order to obtain greater reimbursement from the insurance company. The control group had instructions to honestly assess the probability of occurrence of the symptoms. Results. The results of the multivariate one-way analysis of variance suggested that the effect of experimental manipulation was statistically significant [F (88, 5) = 91.21, p < 0.001; ?2p = 0.838]. Univariate effects were also statistically significant for all five scales. Participants in the malingerer group scored higher on all five scales than participants in the control group. The magnitudes of the effects support the largest differences between the malingerer and control groups on the scales of Memory Disorders and Neuro-logical Disorders, which was also the basic instruction for simulating symptoms given to the participants in the malingerer group. Conclusion. The obtained results support the discriminant validity of the SIMS questionnaire in the situation of simulating symptoms of neurological disorders and memory disorders.

Symptom and performance validity in neuropsychological assessments of outpatients 15-30 years of age

ABSTRACT Objective It has been suggested that performance validity tests (PVTs) assess the credibility of a patient’s objective test performance, symptom validity tests (SVTs) assess the credibility of a patient’s subjective complaints, and that PVTs and SVTs are independent measures. The aim of this study was to test this hypothesis and investigate the associations of PVTs and SVTs with cognitive tests and self-reported measures. Method Patients 15–30 years of age were consecutively recruited from a neurorehabilitation outpatient clinic. The participants completed a battery of cognitive tests and self-reporting questionnaires as well as the Test of Memory Malingering (TOMM) and the Structured Inventory of Malingered Symptomatology (SIMS). Results Forty-eight neurological patients of various etiologies were included. The TOMM (PVT) was related to cognitive tests across cognitive domains and unrelated to self-reporting measures. The SIMS (SVT) was related to other self-reported measures of perceived stress, anxiety, and depression, though also related to cognitive test of attention and processing speed. The PVT and the SVT were unrelated and hence seemed to measure two different constructs of validity. Conclusions This study supports the definition of PVTs and SVTs as two independent measures, consequently that both should be applied routinely in neuropsychological assessments.

The Impact of Different Forms of Coaching on the Structured Inventory of Malingered Symtomatology (SIMS).

Psychometric symptom validity instruments (SVTs) can be vulnerable to coaching, which can negatively affect their performance. Our aim was to assess the impact that different types of coaching may have on the sensitivity of the Structured Inventory of Malingered Symptomatology (SIMS). A simulation design was used with 232 non-clinical adults divided into five experimental simulation conditions and 58 patients with anxious-depressive symptomatology derived from a traffic accident. All simulators received a basic scenario and, in addition, the second group was instructed on the symptomatology, the third was warned about the risk of exaggerating the presentation, the fourth received a combination of the two previous groups and the fifth received specific training on SVTs. The discriminative ability of the SIMS was higher in the basic and symptom information groups, and it decreased significantly in the specific training group on SVTs. SIMS seems not to be severely impacted by a variety of symptom coaching styles, although test coaching diminished its performance.

Machine learning item selection for short scale construction: A proof-of-concept using the SIMS

ObjectiveThis proof-of-concept paper provides evidence to support machine learning (ML) as a valid alternative to traditional psychometric techniques in the development of short forms of longer parent psychological tests. ML comprises a variety of feature selection techniques that can be efficiently applied to identify the set of items that best replicates the characteristics of the original test. MethodsIn the present study, we integrated a dataset of 329 participants from published and unpublished datasets used in previous research on the Structured Inventory of Malingered Symptomatology (SIMS) to develop a short version of the scale. The SIMS is a multi-axial self-report questionnaire and a highly efficient psychometric measure of symptom validity, which is frequently applied in forensic settings. Results State-of-the-art ML item selection techniques achieved a 72% reduction in length while capturing 92% of the variance of the original SIMS. The new SIMS short form now consists of 21 items. ConclusionsThe results suggest that the proposed ML-based item selection technique represents a promising alternative to standard psychometric correlation-based methods (i.e. item selection, item response theory), especially when selection techniques (e.g. wrapper) are employed that evaluate global, rather than local, item value.

The English-language version of the Self-Report Symptom Inventory: a pilot analogue study with feigned head injury sequelae

Questionnaire-based symptom validity tests (SVTs) are an indispensable diagnostic tool for evaluating the credibility of patients’ claimed symptomatology, both in forensic and in clinical assessment contexts. In 2019, the comprehensive professional manual of a new SVT, the Self-Report Symptom Inventory (SRSI), was published in German. Its English-language version was first tested in the UK. This experimental analogue study investigated 20 adults simulating minor head injury symptoms and 21 honestly responding participants. The effect sizes of differences between the two groups were large, with the simulating group endorsing a higher number of pseudosymptoms, both on the SRSI and the Structured Inventory of Malingered Symptomatology, and scoring lower on the Reliable Digit Span than the control group. The results are similar to those obtained in previous research of different SRSI language versions, supporting the effort to validate the English-language SRSI version.

Symptom coaching and symptom validity tests: An analog study using the structured inventory of malingered symptomatology, Self-Report Symptom Inventory, and Inventory of Problems-29

In this pilot and exploratory study, we tested the robustness of three self-report symptom validity tests (SVTs) to symptom coaching for depression, with and without additional information available on the Internet. Specifically, we divided our sample (N = 193) so that each subject received either the Structured Inventory of Malingered Symptomatology (SIMS; n = 64), the Self-Report Symptom Inventory (SRSI; n = 66), or the Inventory of Problems-29 (IOP-29; n = 63). Within each of the three subgroups, approximately one third of participants were instructed to respond honestly (Genuine Condition, n SIMS = 21; n SRSI = 24; n IOP-29 = 26) and approximately two-thirds were instructed to feign depression. One half of the feigners were presented with a vignette to increase their compliance with instructions and were given information about symptoms of depression (Coached Feigning, n SIMS = 25; n SRSI = 18; n IOP-29 = 21), and the other half were given the same vignette and information about symptoms of depression, plus two Internet links to review before completing the test (Internet-Coached Feigning, n SIMS = 18; n SRSI = 24; n IOP-29 = 16). Overall, the results showed that the genuine conditions yielded the lowest total scores on all three measures, while the two feigning conditions did not significantly differ from each other. Looking at the detection rates for all feigning participants, all three measures showed satisfactory results, with IOP-29 performing slightly better than SIMS and SIMS performing slightly better than SRSI. Internet-Coached Feigners scored slightly lower on all three measures than feigners who were coached without the Internet links. Taken together, the results of this preliminary and exploratory study suggest that all three SVTs examined are sensitive to feigned depression even in the presence of symptom coaching, both with and without additional Internet-based information.

Scores in Self-Report Questionnaires Assessing Adult ADHD Can Be Influenced by Negative Response Bias but Are Unrelated to Performance on Executive Function and Attention Tests

Self-report questionnaires are in widespread use in the assessment of adults with suspected attention-deficit and hyperactivity disorder (ADHD). Notwithstanding the high degree of validity, these questionnaires are considered to possess, their stand-alone use in assessment for adult ADHD may result in false-positive diagnoses due to the risk of negative response bias. Most of the self-report questionnaires in typical use are based on the diagnostic systems DSM-5 or ICD-10. From a neuropsychological point of view, however, testing of various executive function abilities and attentional performance is important in the assessment of adult ADHD. The present study (N = 211) found no evidence linking executive function (working memory and inhibitory processes) and attentional performance (processing speed) to the results of a self-report questionnaire, the ADHS-LE. The number of failures on the three symptom or performance validity tests (SVT/PVT) used provided the sole, and significant, explanation for the response behavior reported on the ADHS-LE. Of these three SVT/PVTs (the German version of the Structured Inventory of Malingered Symptomatology, SIMS, the reliable digit span, and the standard deviation of simple reaction time), only the SIMS was found to be a significant predictor variable. In the clinical context of this study, 32.6% of subjects produced at least one invalid SVT/PVT result. The use of a more conservative criterion—failure on at least two of the three SVT/PVTs deemed to be feigning ADHD—reduced the proportion of participants generating invalid values to 5%.

Self-reported neurobehavioral symptoms in combat veterans: An examination of NSI with mBIAS symptom validity scales and potential effects of psychological distress.

This study evaluated symptom validity scales from the Neurobehavioral Symptom Inventory (NSI) and mild Brain Injury Atypical Symptom Scale (mBIAS) in a sample of 338 combat veterans. Classification statistics were computed using the Structured Inventory of Malingered Symptomatology (SIMS) as the validity criterion. Symptom distress was assessed with the Patient Health Questionnaire-9 and Posttraumatic Stress Disorder (PTSD) Checklist-5. At SIMS > 14, the NSI total score resulted in the highest area under the curve (AUC; .91), followed by Validity-10 (AUC = .88) and mBIAS (AUC = .67). At SIMS > 23, both NSI total and Validity-10 AUCs decreased to .88; in contrast, mBIAS AUC increased to .75. The NSI total score and Validity-10 were interpreted to reflect symptom magnification, whereas the mBIAS may reflect symptom fabrication. There was a subsample with elevated Patient Health Questionnaire-9 (PHQ-9) and PTSD Checklist-5 scores who were significantly distressed but not deemed invalid on the NSI; however, there appears to be an upper threshold on the NSI total score (>69) beyond which nobody produced an invalid score on the SIMS. A recommended approach is provided for using NSI-related validity measures. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Exploring the Structured Inventory of Malingered Symptomatology in Patients with Multiple Sclerosis

Exploring the Structured Inventory of Malingered Symptomatology in Patients with Multiple Sclerosis

Validity of the "Structured Inventory of Malingered Symptomatology" [SIMS] in the Assessment of Healthy Individuals and Patients with Psychiatric Disorders Outside the Forensic Context

Assessment of the rate of false-positive results of the Structured Inventory of Malingered Symptomatology (SIMS) in healthy controls and authentic patients outside the forensic or rehabilitative context. Beyond the SIMS scores, further variables (PANSS, Hamilton scale, MMSE) were obtained. SIMS scores of healthy individuals were compared with the SIMS scores of the different groups of patients. Additionally, correlations between the SIMS scores and other variables were investigated. Patients with psychotic disorders (n=30) or depressive episodes (n=32) more frequently achieved SIMS scores >16 as compared to healthy controls. In comparison, patients with amnestic disorders (n=15) had inconspicuous SIMS scores. Depressed patients with positive SIMS results were significantly more likely to be diagnosed with another psychiatric disorder and the scores of these patients on the Hamilton scale were correlated with positive results on 2 subscales of the SIMS (NI, AF). If this instrument is to applied in clinical practice in the future, further validation of the SIMS is necessary. The specificity of the SIMS seems to be context-related.

How good are inpatients at feigning Miranda abilities?: An investigation of the Miranda Quiz, Inventory of Legal Knowledge, and Structured Inventory of Malingered Symptomatology.

The current study represents the first investigation into feigned Miranda abilities using an inpatient population. We investigated the use of a very generic measure (i.e., the Structured Inventory of Malingered Symptomatology, or SIMS) as well as two specialized forensic feigning measures: the Miranda Quiz (MQ) and Inventory of Legal Knowledge (ILK). With a quasi-random assignment, 82 acute inpatients were evenly distributed to "feigning" and "genuine" groups. The recommended SIMS cut score >14 performed poorly, misclassifying three-quarters of the genuine group as feigning. In general, sensitivities on the specialized scales were constrained by the general lack of severe decrements for the feigning group. However, specificities were strong to outstanding. In particular, the MQ floor effect showed some promise but was limited by its small number of items. The strongest potential was observed for the revised ILK scales, especially the Revised Clinical ILK (RC-ILK). When using single-point cut scores on two prior correctional samples, the RC-ILK produced excellent sensitivities (0.94 and 0.96) and outstanding specificities (0.98 and 0.99). Methodological issues and professional implications were discussed in the context of feigned Miranda abilities.

Symptom Profile of Injured Motorists on the Structured Inventory of Malingered Symptomatology

Background: Recent extensive content analyses demonstrated that the items of the Structured Inventory of Malingered Symptomatology (SIMS) have no capacity to differentiate malingerers from legitimate medical patients: all items list or assess legitimate medical symptoms. We examined which SIMS items are the most frequently endorsed by injured motorists. Method: De-identified archival data of 23 survivors (mean age=38.0, SD=12.8) of high impact motor vehicle accidents (MVAs) contained their SIMS scores, their responses to the Brief Pain Inventory, Morin’s Insomnia Severity Index, Rivermead Post-Concussion Symptoms Questionnaire, and to the Post-MVA Neurological Symptoms scale. Results: All SIMS items which were endorsed by more than 43% of the patients in the directions scored by the SIMS as indicative of “malingering” were selected. Twenty-five items met this criterion. On a closer examination, all these 25 items are legitimate psychological and neuropsychological symptoms typically experienced by injured motorists, such as depression, impaired sleep, and postconcussive symptoms (memory and concentration problems, impaired balance) and whiplash symptoms (numbness in the limbs, instances of reduced muscular control over some of the limbs). Discussion and Conclusions: The 25 endorsed items are consistent with the polytraumatic symptom profile of injured patients. In a travesty of psychological assessment, these symptoms are scored in the SIMS as denoting “malingering”.

Flawed Studies of SIMS’s Diagnostic Accuracy by Teams of Puente-López and Capilla Ramírez

Background: The teams of Puente-López and Capilla Ramírez evaluated diagnostic accuracy of the Structured Inventory of Malingered Symptomatology (SIMS), a test often used to assess malingering by persons injured in motor vehicle accidents (MVAs). Yet all SIMS items represent legitimate medical symptoms, and more than 50% of them are those experienced by severely injured motorists, but they are fallaciously scored as indicative of malingering. Thus, more injured patients with more symptoms obtain higher SIMS scores for malingering. Method: The studies by Puente-López and by Capilla Ramírez were carried out on SIMS scores of injured motorists. The present article assesses the severity of their injuries, as documented by Puente-López and by Capilla Ramírez. Results and Discussion: The study by Capilla Ramírez’s team excluded patients with pathological results on physical examinations, or on X-Rays, EMG, and MRI: thus, only mildly injured motorists were included. The patients of Puente-López had signs of only a mild cervical whiplash. Almost none reported lower back pain or dizziness. Thus, both studies included patients with only mild symptoms that resulted in very low SIMS scores: they scored within the non-malingering range as defined by the SIMS manual. Their scores were below SIMS scores of healthy persons instructed to feign whiplash symptoms from an MVA. The teams of Capilla Ramírez and of Puente-López erroneously interpreted these results as demonstrating diagnostic accuracy of the SIMS for detection of malingering in injured motorists. Conclusions: The two studies of very mildly injured motorists fail to demonstrate “diagnostic accuracy of the SIMS” because the SIMS is mostly used by insurance contracted psychologists on more severely injured MVA patients (those with whiplash and post-concussion syndrome), i.e., those with more symptoms and thus, with higher SIMS scores that fallaciously classify them as “malingerers.”

High elevation rates of the Structured Inventory of Malingered Symptomatology (SIMS) in neuropsychological patients

The current study examined characteristics of the Structured Inventory of Malingered Symptomatology (SIMS) in a sample of 110 patients at an adult neuropsychology clinic. Subjects with especially high or low suspicion of invalid reporting were identified based on clinician-completed questions. SIMS elevation rates were examined at different cutoffs and between these groups and were correlated with other indicators of validity. High rates of SIMS elevations were found at the standard cutoff (>14) for the total sample (45.5%), low suspicion cases (24.4%), and high suspicion cases (95.7%). Other indicators of invalidity were low (secondary gain = 8.5%, clinical suspicion of exaggeration in interview M = 2.37/5, medical records concerning for invalidity = 2.4%, mixed/poor performance validity = 6.1%). Elevations correlated with clinician concern for over-reporting in interview, subject-reported cognitive concern (r = −.610) and psychological measures (BDI-II r = −.602, PROMIS r = −.409) but not with neuropsychological memory tests or performance validity measures (all p > .23). The SIMS should be interpreted with caution, as elevations appeared largely related to cognitive concern and psychiatric distress rather than true malingering. A cutoff of > 16 could be used in neuropsychological populations, although this is still of modest specificity.

The utility of the Structured Inventory of Malingered Symptomatology for distinguishing individuals with Dissociative Identity Disorder (DID) from DID simulators and healthy controls

ABSTRACT Background: Individuals with dissociative identity disorder (DID) have complex symptoms consistent with severe traumatic reactions. Clinicians and forensic assessors are challenged by distinguishing symptom exaggeration and feigning from genuine symptoms among these individuals. This task may be aided by administering validity measures. Objective: This study aimed to document how individuals with DID score on the Structured Inventory of Malingered Symptomatology (SIMS). The second objective was to compare coached DID simulators and healthy controls to DID patients on the SIMS’s total score and subscales. The third objective was to examine the utility rates of the SIMS in distinguishing simulated DID from clinically diagnosed DID. Method: We compared SIMS data gathered from participants from two Dutch sites, one Swiss site and one U.S. site. Sixty-three DID patients were compared to 77 coached DID simulators and 64 healthy controls on the SIMS. A multivariate analysis compared the groups on the SIMS total scores and subscales, and post-hoc Games Howell tests and univariate ANOVAs examined differences between the groups. Utility statistics assessed the accuracy of the SIMS in distinguishing clinical from simulated DID. Results: DID simulators scored significantly higher than DID individuals and healthy controls on every SIMS subscale as well as the total score. The majority (85.7%) of the individuals with DID scored above the cut-off, which is typically interpreted as indicative of possible symptom exaggeration. DID individuals scored higher than the healthy controls on every subscale except Low Intelligence, even after controlling for dissociation. The subscales and items most frequently endorsed by the DID group are consistent with symptoms associated with complex trauma exposure and dissociative reactions. The SIMS total score had a sensitivity of 96% but an unacceptably low specificity of 14%. Conclusions: The findings indicate that the instrument is not accurate in assessing potential symptom exaggeration or feigning in DID.