The Detection of Malingering in Criminal Forensic Groups: MMPI Validity Scales

Abstract

Despite the value of the MMPI to the forensic assessment of malingering (exaggeration) of psychopathology, few studies have assessed the accuracy of the MMPI validity scales in criminal forensic populations. We administered the MMPI to 35 insanity defendants undergoing evaluation for fitness to stand trial and/or sanity at the time of the crime, who stood to benefit from being assessed as psychologically disturbed, and 39 subjects previously found not guilty by reason of insanity (NGRI), who did not stand to gain from such an assessment, Insanity defendants showed significantly more malingering than NGRI subjects, p less than .05. Racial differences did not affect the data. These findings support the efficacy of MMPI validity scales in assessing malingering within criminal forensic groups, and support the generalizability of the scales across race.

Potential for Bias in MMPI-2 Assessments Using the Fake Bad Scale (FBS)

“…However, the MMPI F scale has been researched in both experimentally controlled simulation research (e.g., Bagby et al 1995;Elhai et al 2000;Graham et al 1991;Hunt 1948) and in "real world" studies as well, including correctional settings (e.g., Grossman and Wasyliw 1988;Moskowitz et al 1999;Wasyliw et al 1988); compensation cases (e.g., Charles 2000); inpatients (e.g., Gynther and Petzel 1967;Post and Gasparikova-Krasnec 1979); and with suicidal patients (e.g., Rissmiller et al 1998), to mention only a few. Furthermore, like F, the FBS was developed using the MMPI item pool initially to identify those "simulating or exaggerating emotional distress" from those "who are not malingering" (Lees-Haley et al 1991, p. 203).…”

Differential patterns of responding among three groups of chronic, psychotic, forensic outpatients

“…In forensic populations, denial and defensiveness have been attributed to a socially desirable response set (Bagby et al, 1994;Roman et al, 1990;Wasyliw et al, 1988) and the use of primitive defensives such as denial (Coyle & Heap, 1965;Fjordbak, 1985;Gacono & Meloy, 1994;Meloy, 1988;Weiner, 1966); however, factors such as illness chronicity, stabilization on psychotropic medications, cognitive and emotional impoverishment, and/or the influence of concurrent character pathology (Gacono & Meloy, 1994;Meloy, 1988) may also shape the response style in forensic psychiatric patients. Since multiple factors influence test results, protocol constriction or expansion-when they occur-require special interpretation within the forensic assessment (Gacono & Meloy, 1994;Meloy & Gacono, 1995;Melton et al, 1998).…”

A limitation of using the wiener and harmon obvious and subtle scales to detect faking on the MMPI

“…The ability of Obvious and Subtle scores to detect deliberate exaggeration of psychopathology became the focus of several later studies (Anthony, 1971 ;Gendreau, Irvine, & Knight, 1973;Greene, 1988; Grow, McVaugh, & Eno, 1980; Harvey & Sipprelle, 1976; Hsu, Santelli, & Hsu, 1989;Peterson, Clark, & Bennett, 1989;Walters, White, & Greene, 1988;Wasyliw, Grossman, Haywood, & Cavanaugh, 1988). Without exception, these studies show that subjects who are told to "fake bad," or are suspected of faking bad, endorse more Obvious items than subjects told to "fake good" or answer honestly.…”

“…Paradoxically, Subtle scores decline slightly under "fake bad" conditions (Dubinsky et al, 1985). Fakers also have been shown to produce larger Obvious minus Subtle ( 0 -S ) difference scores than nonfakers (Grow et al, 1980;Walters et al, 1988;Wasyliw et al, 1988).…”

“…Walters et al (1988) found that a low Subtle score on scale 2 (D) was the most sensitive indicator of exaggeration. Wasyliw et al (1988) compared one group of forensic patients who had an incentive to malinger psychiatric symptoms with another group who had no such incentive and found that an 0 -S T score difference > 160 optimally differentiated the two groups. Greene (1988) argued that 0 -S differences of >20 T score points on every scale probably indicate "overreporting" of symptoms.…”