Depression clearly is an important entity in the differential diagnosis of dementia.
An adequate therapeutic trial of an antidepressant may be necessary to make the diagnosis. With less toxic antidepressant drugs available today, a drug trial is a viable option for helping to distinguish depression from dementia. In neurodegenerative dementing illnesses, different parts of the brain are affected at different rates in individual patients, which causes much variability in patient presentation. For example, patients in whom frontal lobe degeneration occurs earlier may initially display depression-like withdrawal. In addition, patients with dementia may suffer from neurochemically based depression syndrome so often seen in patients after stroke.