NEUROPSYCHOLOGICAL DEFICITS IN SCHIZOPHRENICS - RELATIONSHIP TO AGE, CHRONICITY, AND DEMENTIA

Background: We sought to determine whether neuropsychological impairme nt in schizophrenia is related to current age, age at onset, or durati on of illness, and whether the pattern of such impairment can be disti nguished from that caused by progressive dementias of Alzheimer's type . We administered a comprehensive neuropsychological test battery to a normal control group (n=38), a group of ambulatory patients with Alzh eimer's disease (n=42), and three ambulatory schizophrenic groups: ear ly onset-young (n=85), early onset-old (n=35), and late onset (n=22). Tests were grouped and analyzed according to eight major ability areas , and published procedures were used to remove the expected effects of normal aging. Results: The three schizophrenic groups were found to b e neuropsychologically similar to one another and different from norma l controls and patients with Alzheimer's disease. There were no signif icant differences among the schizophrenic groups in level or pattern o f neuropsychological functioning. Patients with Alzheimer's disease de monstrated less efficient learning and particularly more rapid forgett ing than did the other groups. Conclusions: These findings suggest tha t neuropsychological impairment in schizophrenia is unrelated to curre nt age, age at onset, or duration of illness. The study further sugges ts that the encephalopathy associated with schizophrenia is essentiall y nonprogressive and produces a pattern of deficits that is different from that seen in progressive cortical dementias.