Survival in presenile Alzheimer's and multi-infarct dementias.

Duration of survival in patients who had died of presenile Alzheimer's disease (AD) or presenile multi-infarct dementia (MID) in 13 mental hospitals in Scotland are described and contrasted. The duration of survival was significantly longer from symptom onset to death in AD (mean 7.4 years) than in MID (mean 5.8 years). Most of this difference was accounted for by a longer duration between symptom onset and presentation to hospital care in AD (mean 3.2 years) than in MID (mean 2.4 years). Age at onset and gender did not influence survival duration in AD or MID.