Mental health refers to an individual's emotional, psychological, and social well-being, and is more than just the absence of mental illness. It exists on a continuum and includes an ability to enjoy life and realize one's potential. While mental health professionals rely on diagnostic criteria for mental illnesses, some experts argue for a public health model that views mental health as a separate concept aimed at wellness rather than only treating illness.

4. Mortality

10. Aging

13. The issues of an Aging population in which the average of a society is increasing is an important issue in many nations of the world. The societal effects of age are great. Young people tend to commit most crimes, they are more likely to push for political and social change, to develop and adopt new technologies, and to need educations. Older people have different requirements from government as opposed to young people, and frequently differing values as well. Older people are also far more likely to vote and thus have comparatively more political influence.

15. Dividing the lifespan of Aging A human life is often arbitrarily divided into various ages. Because biological changes are slow moving and vary from person to person arbitrary dates are usually set to mark periods of human life. In USA and many other countries, Adulthood legally begins at age of eighteen and nineteen.