Depressive disorders are characterized by persistent feelings of sadness and worthlessness and a lack of desire to engage in formerly pleasurable activities. Depression is not a passing blue mood, which almost everyone experiences from time to time, but a complex mind/body illness that interferes with everyday functioning. It not only darkens one's outlook, it is commonly marked by sleep problems and changes in energy levels and appetite. It alters the structure and function of nerve cells so that it disrupts the way the brain processes information and interprets experience. Despite feelings of hopelessness and worthlessness, depression is a treatable condition. It can be treated with psychotherapy or medication, or a combination of both.
Depression is a common condition in modern life. According to the National Institutes of Health, each year more than 16 million adults in the United States experience at least one episode of major depression. The likelihood that a person will develop depression at some point in life is approximately 10 percent. Prolonged social stress and major disruption of social ties are known risk factors for depression, and major negative life events such as loss of a loved one, or loss of a job, increase the subsequent risk of depression. Significant adversity early in life, such as separation from parents or parental neglect or abuse, may create vulnerability to major depression later in life by setting the nervous system to over-respond to stress.