CORTICAL CHOLINERGIC MARKERS IN SCHIZOPHRENIA

Cortical cholinergic deficits have been implicated in the cognitive de ficits produced by a variety of neurodegenerative diseases including A lzheimer's disease (AD). Recent studies have suggested that many of th e chronically institutionalized geriatric schizophrenic patients are a lso cognitvely impaired. In this postmortem study we compared choliner gic marker activity in six different cortical regions derived from eld erly controls, chronically institutionalized geriatric schizophrenic p atients, and AD patients. All of the Alzheimer's disease cases met neu ropathological criteria for AD, while none of the schizophrenic cases met criteria for AD. Cholinergic marker activity (choline acetyltransf erase and acetylcholinesterase) was significantly diminished in the AD cohort but not in the schizophrenic cohort. Additionally, cortical ch oline acetyltransferase activity was significantly and negatively corr elated with Clinical Dementia Rating scores (CDR), whereas no such cor relations were evident in the schizophrenic cohort. These results sugg est that cognitive deficits in geriatric schizophrenics are not due to diminished cortical cholinergic activity.