Abstract

Objective: The validity of the MMPI Fake Bad Scale has been demonstrated, but continues to be a matter of current debate. This study validated the scale in probable clinical malingerers and nonlitigant patients.

Method: The MMPI-2 was administered to 44 litigating or compensation seeking individuals that claimed cognitive impairment and scored in the probable malingering range on the TOMM, Portland Digit Recognition Test, or Word Memory Test. The MMPI-2 was also administered to 64 non-litigating patients hospitalized for treatment of head trauma. Groups were compared on the FBS and standard MMPI-2 validity scales.

Results: Malingerers averaged significantly higher FBS raw scores (25.3, s = 6.7) than patients (15.8, s = 4.7), and higher F (77.6 vs. 60.7) and Fb (81.2 vs. 59.8) scale T-scores. FBS scores correlated significantly with F (r = .37) and Fb (r = .58) in malingerers but not patients. Hypochondria, Depression, Hysteria, and Psychasthenia were highly correlated with FBS scores (rs > .7). No relationship between the scale and gender, age, or education was observed in either group. Stepwise discriminant function analysis showed that an FBS cutoff score above 20 accurately classified 82.8% of patients and 72.7% of probable malingerers. Other validity scales did not add significantly to diagnostic accuracy. An FBS cutoff greater than 28 correctly identified 100% of patients and 34% of malingerers.

Conclusions: The FBS scale is useful for characterizing malingered cognitive impairment. Diagnostic accuracy can be improved by consideration of specificity, sensitivity, and base rates.