In most countries, it is clear that the costs of care, treatment, and support of people with Alzheimer's disease and other dementias will rise considerably in the next few decades. This paper discusses dementia as an economic concern and looks at the policy questions addressed by the current literature on the costs of dementia. It then considers the policy responses to concerns about the growing cost of dementia, distinguishing between 'hopeful' policies that seek to reduce or contain the costs, and policies to address the capacity of the health, care, and social protection systems to respond to dementia care in a way consistent with public expectations. We conclude that the costs of dementia care do not necessarily equate to dementia care being unsustainable, but they do highlight the need for policy action. Additionally, it is relatively easier for policymakers to adopt 'hopeful' policies, such as investment in research to find a disease modifying treatment for Alzheimer's or strategies for dementia risk reduction, than it is to tackle the more politically complex decisions needed to ensure that health, care, and social protection systems have the capacity to respond to the challenge of dementia.