Living Reference Work Entry

Mental Health and Illness of the Elderly

Part of the series Mental Health and Illness Worldwide pp 1-30

Date: Latest Version

Epidemiology of Mental Disorders (Including Cross-Cultural Comparisons)

  • Ee Heok KuaAffiliated withDepartment of Psychological Medicine, National University Health System, National University of Singapore Email author 
  • , Rathi MahendranAffiliated withDepartment of Psychological Medicine, National University Health System, National University of Singapore


This review covers a wide swathe of the research worldwide on the epidemiology of mental disorders in late life. Data on the prevalence and incidence of mental disorders are important not only for mental health professionals but also health policy makers who have to plan services for an increasing number of elderly people. Although epidemiological data today are mainly from developed countries, in recent years many developing countries have conducted studies on dementia in community-dwelling elderly.

From the published data of elderly populations 65 years and over, the prevalence of depressive disorders is estimated at 2–21% and dementia between 2% and 8%. Most studies have reported a higher prevalence of Alzheimer’s disease than vascular dementia. Research on survival after a diagnosis of dementia indicates a varying period from 5 to 12 years. The reported prevalence of anxiety disorders is 3–14%, and comorbidity of anxiety-depression is high ranging from 40% to 90%. Schizophrenia, bipolar disorder, and other psychotic disorders are less common in old age.

The wide variations in prevalence rates especially for depressive disorders could be due to the differences in sampling methodology, interview instruments, and diagnostic criteria.

Epidemiological studies have identified risk factors which are crucial for early detection and interventions in preventive psychiatry. In the last decade, there are encouraging results from a few interventional programs in the prevention of dementia and depression in late life.


Epidemiology Depression Dementia Anxiety Schizophrenia Elderly