The differential effects of simulating malingering, closed head injury, and other CNS pathology on the Wisconsin Card Sorting Test: support for the "pattern of performance" hypothesis.

We investigated the effects of faking bad on the Wisconsin Card Sorting Test, comparing the performance of simulating malingerers (M; n = 24) to controls (C; n = 21), closed head-injured patients (CHI, n = 70), and patients with mixed CNS pathology other than CHI alone (CNS; n = 89). Stepwise discriminant functions achieved good accuracy (91-96%), sensitivity (58-100%), and specificity (92-100%) in differentiating simulating malingerers from these groups. The Categories score was a consistent significant independent discriminating variable. Categories alone could differentiate between the M and C groups. However, in discriminating between simulating malingerers and both CHI or CNS patients, more complex patterns of performance emerged, consisting of relatively poorer performance ratios on Categories compared to Perseverative Errors. This supported the Pattern of Performance theory of the effects of simulating malingering on neuropsychological tests, which holds that people simulating malingering do more poorly on obvious vs. subtle tasks compared to people with verified brain damage. Due to the difficulty of tracking one's performance on several different indices simultaneously, known patterns of performance for patients with verified brain dysfunction should be very difficult to fake, even with coaching.