A comparison of performance on the Test of Memory Malingering between a forensic and a non-forensic psychiatric population
The purpose of this study was to compare performance on the Test of Memory Malingering (TOMM, Tombaugh, 1996) between a Forensic Psychiatric group and a Non-forensic Psychiatric group. The TOMM is a forced-choices 50-item, visual recognition test developed to aid in the determination of effort. It was hypothesized that significant differences would emerge between groups, with less effort on the part of the Forensic group hypothesized, because of known secondary gain. Each group was composed of 20 adult men. The Forensic group consisted of men who had been referred for pre-trial evaluations to a forensic facility in the southeastern United States. Sixteen of the 20 men were minority race. The Psychiatric group consisted of men from adult inpatient units in the southwestern and southeastern United States. Fifteen of the 20 men were Caucasian. Each participant was administered the Mini-Mental State Examination (MMSE), M-Test, TOMM, Wechsler Adult Intelligence Scales--Third Edition (WAIS-III, Vocabulary and Block Design), and Structured Clinical Interview for DMS-IV Axis II (SCID-II) Antisocial Personality Disorder section. Results suggested that the Psychiatric Group was significantly older (M = 41.00, SD = 10.42 years) than the Forensic Group (M = 32.65, SD = 8.46 years) and had more Caucasian participants (n = 15) than did the Forensic Group (n = 4). The Psychiatric Group was also found to have significantly higher estimated IQ scores (M = 89.85, SD = 19.68) than the Forensic Group (M = 74.40, SD =14.28) and MMSE scores (Psychiatric Group M = 26.45, SD = 2.35; Forensic Group M = 23.80, SD = 3.98). No group differences were found for Education, M-Test, or SCID-II. Significant Group and Trial differences emerged, suggesting that the Psychiatric group performed better on all three TOMM trials. Further, results suggested that both groups performed better on Trial 2 and the Retention Trial when compared with Trial 1. However, in the Forensic group, the total TOMM score was positively correlated with MMSE and Estimated IQ score. ANCOVAs, with MMSE and IQ scores as covariates, revealed no significant group effect. Limitations included the use of volunteers from two different geographical areas, and differences in race and age. Also, the role of intelligence and cognitive functioning in the examinee's performance on the TOMM cannot be ascertained from this study. It appears that the TOMM has utility as a test of malingering for both populations; however, intellect and cognitive functioning need to be carefully considered when drawing conclusions regarding the results of this instrument. Areas of future research would include exploring these relationships further.