['Patients with psychogenic nonepileptic seizures (PNES) and those with epileptic seizures (ES) purportedly have roughly equal neurocognitive deficits. However, recent findings suggest that patients with somatoform disorders exhibit more variable effort on neurocognitive testing than do controls. We reexamined neurocognitive function in patients with ESs and PNES by using symptom validity testing to control for variability in effort.', 'Patients referred for video-EEG monitoring were administered the Word Memory Test (WMT), a measure of symptom validity, as part of neuropsychological evaluation. Patients classified with ictal video-EEG recordings as having ES (n = 41) or PNES (n = 43) were compared on neurocognitive and WMT performance and demographic, psychiatric, and medical variables.', 'Striking rates of WMT failure were observed in the PNES (51.2%) group, but not in the ES (8.1%) group (p = <0.001) after controlling for false-positive errors. Although the PNES and ES groups reported equivalent neurologic histories, the PNES group exhibited less objective evidence of impairment as measured by valid neuropsychological testing, MRI of the brain, and video-EEG monitoring.'] Is cognitive impairment equal in patients with epileptic and psychogenic nonepileptic seizures?