The paradox of normal neuropsychological function in schizophrenia

Mounting evidence suggests that compromised neurocognitive function is a co re feature of schizophrenia. However, some studies have found neuropsycholo gically normal schizophrenia patients. To address this apparent contradicti on, we blindly rated individual neuropsychological profiles of 75 schizophr enia patients and 91 control participants on the basis of methods developed by L. J. Seidman, S. V. Faraone, W. S. Kremen, J. R. Pepple, M. J. Lyons, and M. T. Tsuang (1993). Almost one-quarter of the patients were classified as neuropsychologically within normal limits (WNL). Despite significantly worse neuropsychological performance, WNL patients had higher estimated pre morbid ability than did controls. Compared to a subset of controls matched on overall neuropsychological function, WNL patients had higher estimated p remorbid ability and current IQs. Our results favor the view that even neur opsychologically normal schizophrenia patients have compromised cognitive f unction relative to their presumed expected or premorbid level of intellect ual ability.