Home > Encyclopedia of Psychology > Mental Illness

The term used to describe a disorder or condition that negatively affect cognition (thought), behavior, and/or affect (mood) to such a point where it causes a significant amount of distress and functional impairment for a prolonged period of time.

Overview

Mental illness is a serious public health problem. According to the World Health Organization and the Harvard School of Public Health, mental illness accounts for nearly 11 percent of total worldwide disease burden. (Disease burden is determined by the calculation of DALYs, or disability-adjusted life years. The DALY statistic measures lost years of healthy life from death or disability due to a disease.) In countries that are considered "established market economies" (i.e., United States, Great Britain), mental illness is second only to heart disease as the most...