Frequency of Alzheimer's disease in a postmortem study of psychiatric patients.

The brains from 100 consecutive patients dying in psychiatric departments were subjected to a neuropathological study with a quantitative evaluation of neurofibrillary tangles and senile plaques. Histologically, Alzheimer changes were found in 63.4% of the group with the clinical diagnosis of senile dementia and in 60% of the arteriosclerotic dementia group. In other clinical groups (schizophrenic, manic-depressive, and "other disorders") the percentage of Alzheimer changes was about 30. Thus, Alzheimer changes were not only present in the group of patients with the "correct" psychiatric diagnosis senile dementia, but were also frequent among patients with other psychiatric diseases where no clinical suspicion of Alzheimer's disease had been forecast. Alzheimer's disease may, thus, contribute to or be concealed by other psychiatric diseases and should be considered in all geronto-psychiatric cases.