Nearly 28 million people worldwide with dementia are tragically not been diagnosed as per a new report.

Over 75% of the estimated 36 million people globally living with dementia are not diagnosed. Consequently, they do not benefit from treatment and care.

Commissioned by Alzheimer's Disease International (ADI), the report was compiled by a team of researchers led by Professor Martin Prince at the Institute of Psychiatry, King's College, London.

The report is really mainly about the estimated 28 million out of 36 million people worldwide with dementia who don't have a diagnosis, said Professor Martin Prince.

The report found governments could save billions if they focused on earlier diagnosis, for example, reducing the need for care at home or at the hospital.

Recent studies suggest the disease starts developing at least a decade before any symptoms appear.

Dementia is not merely a problem of memory. It reduces the ability to learn, reason, retain or recall past experience and there is also loss of patterns of thoughts, feelings and activities.

Additional mental and behavioral problems often affect people who have dementia, and may influence the quality of life, caregivers and the need for institutionalization. As dementia worsens individuals may neglect themselves.

Proper differential diagnosis between the types of dementia (cortical and subcortical) will require, at the least, referral to a specialist. The duration of symptoms must be evident for at least six months for a diagnosis of dementia or organic brain syndrome to be made.

Dementia is much less common under 65 years of age. Alzheimer's disease is still the most frequent cause, but inherited forms of the disease account for a higher proportion of cases in this age group. Frontotemporal lobar degeneration and Huntington's disease account for most of the remaining cases.

Currently, there are no medications that are clinically proven to be preventative or curative of dementia. Although some medications are approved for use in the treatment of dementia, these treat the behavioral and cognitive symptoms of dementia, but have no effect on the underlying pathophysiology.

Persistent pain in the person with dementia is difficult to communicate, diagnose and treat. Failure to address persistent pain has profound functional, psychosocial and diminished quality of life implications for this vulnerable population.