About 18.8 million American adults experience a depressive illness that involves the body, mood, and thoughts. Depression affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. People with a depressive illness cannot just "pull themselves together" and get better. Without treatment, symptoms can last for weeks, months, or years.  Major depressive disorder involves a pervading sense of sadness and/or loss of interest or pleasure in most activities that interferes with the ability to work, study, sleep, eat, and enjoy once pleasurable activities. This is a severe condition that can impact a person's thoughts, sense of self worth, sleep, appetite, energy, and concentration. The condition can occur as a single debilitating episode or as recurring episodes.
Dysthymia involves a chronic disturbance of mood in which an individual often feels little satisfaction with activities of life most of the time. Many people with dysthymia also experience major depressive episodes in their lives leading to a recurrent depressive disorder. The average length of an episode of dysthymia is about four years.
The most important thing to do for people with depression is to help them get an appropriate diagnosis and treatment. Treatment, usually in the form of medication or psychotherapy, can help people who suffer from depression.