What exactly is Dementia

 Dementia, a group of disorders characterized by a decline from a previously attained cognitive level that affects activities of daily living (ADL) and social functioning, poses one of the greatest global challenges for health and social care in the 21st century.

In 2015, dementia affected 50 million people worldwide (or roughly 5% of the world’s elderly population, i.e. those above the age of 60 years). The number of people with dementia is expected to increase to 82 million in 2030 and 152 million by 2050 with the estimated proportion of the population aged 60 and over with dementia at a given time between 5 to 8% 1 because dementia rises exponentially during old age and the world’s population is ageing. These projections assume constant age- and sex-specific prevalence of dementia over time, and, accordingly, the steepest rises are expected especially in low- and middle-income countries (LMIC), where the demographic changes will be more marked.

Dementia is a major cause of disability and dependency among older people worldwide, and it has a significant impact not only on individuals but also on carers, families, communities and societies. Dementia accounts for 11.9% of the years lived with disability due to a noncommunicable disease (NCD) worldwide. Dementia leads to increased costs for governments, communities, families and individuals, and to loss in productivity for economies. The annual global cost of dementia is estimated to be US$ 818 billion (OECD, 2015; WHO, 2017b). Nearly 85% of costs are related to family and social, rather than medical, care (GBD 2015 Neurological Disorders Collaborator Group, 2017). Most health systems are ill-equipped and under-resourced to respond to the current needs associated with dementia. Thus, societal ageing and the associated increases in dementia prevalence will likely have major health-service implications for the care of people with dementia and support for affected families.

There are many different causes and types of dementia. Primary dementias include dementia due to Alzheimer's disease (AD), vascular dementia, dementia with Lewy bodies and frontotemporal dementia (in which the decline in cognitive abilities itself is mostly due to an underlying neurodegenerative process and not directly caused by other etiologies). Alzheimer's disease is the most common, followed by vascular dementia and dementia with Lewy bodies. Mixed dementia with features of more than one type is also common, especially in older adults, while frontotemporal dementia is a less common form but relatively more frequent before old age.

Secondary dementias are those caused by, or closely related to, some other recognizable disease, such as HIV, head injury, multiple sclerosis, thyroid disorders or vitamin B12 deficiency. In these secondary dementias, cognitive impairment is typically accompanied by symptoms and signs in other organ systems and the treatment focuses on the management of the underlying disease.