The term mental health is commonly used in reference to mental illness. However, knowledge in the field has progressed to a level that appropriately differentiates the two. Although mental health and mental illness are related, they represent different psychological states.
Mental health is “a state of well-being in which the individual realizes his or her own abilities, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to his or her community.”1 It is estimated that only about 17% of U.S adults are considered to be in a state of optimal mental health.2 There is emerging evidence that positive mental health is associated with improved health outcomes.
Mental illness is defined as “collectively all diagnosable mental disorders” or “health conditions that are characterized by alterations in thinking, mood, or behavior (or some combination thereof) associated with distress and/or impaired functioning.”2 Depression is the most common type of mental illness, affecting more than 26% of the U.S. adult population.3 It has been estimated that by the year 2020, depression will be the second leading cause of disability throughout the world, trailing only ischemic heart disease.4
Evidence has shown that mental disorders, especially depressive disorders, are strongly related to the occurrence, successful treatment, and course of many chronic diseases including diabetes, cancer, cardiovascular disease, asthma, and obesity5 and many risk behaviors for chronic disease; such as, physical inactivity, smoking, excessive drinking, and insufficient sleep.