Depression refers both to a serious mental disorder and to a normal mood involving sadness that all people occasionally experience. The duration and grouping of symptoms distinguishes depression as a mental disorder from occasional feelings of sadness. This article discusses depression as a disorder. Medical experts believe that depression causes more disability throughout the world than almost any other medical illness or disorder.
Most people suffering depression feel sad, become irritable, or lose interest in work or social activities. The medical diagnosis of depression requires at least one of these features to be present nearly every day for at least two weeks. In addition, the diagnosis requires four or more of the following symptoms: feelings of worthlessness or guilt, chronic fatigue, difficulty concentrating, significantly increased or decreased appetite, slowed thinking and movements, significantly increased or decreased sleep, or thoughts of suicide. If this group of symptoms occurs nearly every day for weeks, it forms what mental health professionals call a depressive episode.
Depressive episodes can occur alone, or they may alternate with manic episodes (periods of uncontrolled, excessive joy or overactivity) in a disorder called bipolar disorder. Some depressive episodes develop in the autumn and winter and disappear in the spring and summer in a condition known as seasonal affective disorder.
Research suggests that some people have a genetic tendency to develop depression. Scientists have also identified genes that may influence the development of depression. The genes affect the development of brain cells and neurotransmitters (chemicals that carry messages among nerve cells).
Experiences in life can also lead to depression in some people. People may become depressed under certain circumstances, such as abuse, deprivation, loss of a loved one, or loss of a job. Medical experts believe that in depression, as with many mental disorders, heredity and environmental factors interact in the development of the disorder.
Treatments for depression include drugs called antidepressants. The most prescribed antidepressant in the United States is fluoxetine (marketed under the name Prozac). Many patients benefit from psychotherapy that focuses on improving thinking, problem solving, improving personal relationships, or increasing pleasurable activities. Physicians may prescribe electroconvulsive therapy if medication and psychotherapy fail. When depression is severe, patients may require hospitalization. Most people suffering depression improve with treatment.
