What is major depressive disorder?

Major Depressive Disorder impairs a person's ability to work, sleep, eat, and function as he or she normally would. This illness keeps people from enjoying activities that were once pleasurable, and causes them to think about themselves and the world in negative ways. Major depression is often disabling and may occur several times in a person's lifetime. For example, University students with depression are twice as likely as their classmates to drop out of school, new research shows. The depression symptom of loss of interest was directly associated with lower grade point averages and the drop out rate.

Major depressive disorder refers to a well-defined group of symptoms. For an episode to be considered a major depressive disorder it must present with five or more of the following symptoms, present during most of the day, nearly every day, for a minimum of two consecutive weeks. At least one symptom must be either depressed mood or loss of interest or pleasure. The other symptoms include insomnia or hypersomnia, change in appetite or weight, psychomotor retardation or agitation, low energy, poor concentration, thoughts of worthlessness or guilt, and recurrent thoughts about death or suicide.