Elderly patients with schizophrenia exhibit infrequent neurodegenerative lesions

Immunohistochemistry and conventional stains were used to examine the brains of 10 elderly patients with both schizophrenia and dementia to characterize the neuropathology of their cognitive deterioration. Control cases included five nondemented elderly patients with schizophrenia, five age-compatible Alzheimer's disease (AD) patients, and five neurologically normal elderly patients. Only one of the patients with schizophrenia and dementia had AD, another was diagnosed with adult polyglucosan body disease, and the others were devoid of neuropathology that could account for dementia. Quantitation of immunohistochemically detected neurofibrillary tangles and senile plaques revealed similarly low counts for the normal control group and both schizophrenia groups. Typically, the neuropathological causes of dementia can be identified in up to 95% of cases, with AD accounting for 50-60%. The unexpected lack of neuropathological findings to explain the cognitive deterioration in this group of elderly patients with schizophrenia prompts speculation about alternative etiologies.