Young-Onset Dementia: Unanswered Questions and Unmet Needs

We think of dementia as an illness of the old. Regan described the senility of her father, King Lear, as “the infirmity of his age.”¹ However, dementia can affect younger or middle-aged adults. Approximately 200 000 Americans younger than 65 years have dementia.² Young-onset dementia (YOD) represents 4% to 10% of all dementia cases.² By convention, YOD is defined as dementia occurring before age 65 years, although this age criterion is a sociological construct.