Chapter 8.Dementia and Mild Neurocognitive Disorders

Dementia is a clinical syndrome that can be caused by a range of diseases or injuries to the brain. Although it can affect young people, it is most commonly seen in older individuals because dementia prevalence increases with age. Alzheimer’s Disease International estimates that approximately 35.6 million individuals were living with dementia worldwide in 2010 (Prince et al. 2013); considering its high prevalence and worldwide distribution, dementia should now be considered a pandemic. Given the dramatic growth of the older population (for instance by 2050, the number of people ages 60 years and older worldwide will have increased by 1.25 billion and account for 22% of the world’s population), the number of people living with dementia worldwide is expected to approximately double every 20 years to 65.7 million in 2030 and 115.4 million in 2050 (Prince et al. 2013) (Figure 8–1). The Alzheimer’s Association (Theis et al. 2013) estimates that 5.2 million Americans are living with Alzheimer’s disease (AD), the single most common cause of dementia. About 11% of people ages 65 years and older and about 32% of the oldest old (those age 85 and older) has AD. AD is the sixth leading cause of death in the United States (Theis et al. 2013). Given the chronicity of dementia, with estimates of its duration ranging from 3–4 years in community settings (Graham et al. 1997) to 10–12 years in clinical settings (Rabins et al. 2006), it poses a unique public health problem with serious effects on its victims, their families, and society at large. For example, the Alzheimer’s Association (Theis et al. 2013) estimated that in the United States, annual direct and indirect expenses of caring for people with AD and other dementias will soar from an estimated $203 billion in 2013 to a projected $1.2 trillion annually by 2050.