Over the years, many myths have evolved about what Alzheimer's disease is, who gets it and how it affects people who have it. These myths can add to the stigma attached to the disease and stand in the way of our ability to understand and help people with it. At the Alzheimer Society, we believe the sooner we dispel the myths, the better we'll be able to respond to the reality. Alzheimer's disease is a progressive, degenerative disease of the brain. It most often occurs in people over 65, but can affect adults at an earlier age.