Symptom validity test failure indicates invalidity of neuropsychological tests.

Neuropsychological and symptom validity test results from 220 archival cases were analyzed to determine if failing a symptom validity test (SVT) affects the relationship between neuropsychological tests and brain damage. Results reveal that among those who failed either the Word Memory Test (WMT) or the Computerized Test of Attention and Memory (CTAM) there was no correlation between the results of 25 commonly used neuropsychological tests and objectively determined brain damage. For those who passed SVTs, the expected relationship between neuropsychological tests and brain damage was found. Consistent with earlier findings, effort had a greater effect on test performance than did brain damage. SVT performance was not correlated with either brain damage or the presence of external incentives. Results indicate the need for symptom validity testing in all cases and that failure of a single SVT can invalidate the expected brain-behavior relationship that underlies neuropsychological test interpretation.