DISPROPORTIONATE LOSS OF NORADRENERGIC AND CHOLINERGIC NEURONS AS CAUSE OF DEPRESSION IN ALZHEIMERS-DISEASE - A HYPOTHESIS

Forty-two patients with neuropathologically confirmed Alzheimer's dise ase, who had been examined prospectively, had a significant decrease o f neuron numbers in the locus coeruleus, substantia nigra, and basal n ucleus of Meynert compared to 10 age-matched, non-demented controls. A subgroup of 12 demented patients with a history of depression had sig nificantly lower neuron numbers in the locus coeruleus and slightly hi gher neuronal density in the basal nucleus of Meynert. We hypothesize that a noradrenergic/cholinergic imbalance may promote the development of depressive features in patients with Alzheimer's disease.