(In other classificatory systems called major depression; depressed manic-depressive disorder) occurs in a person who has never had an episode of mania and is characterized by significant lowering of the mood and loss of interest or pleasure in daily activities, plus a range of other symptoms that may include significant weight or appetite changes, insomnis or hypersomnis, psychomotor agitation or retardation, fatigue or loss of energy, feelings of worthlessness or excessive and inappropriate guilt, diminished ability to think or concentrate, indecisiveness, and recurrent thoughts of death or suicide. Some patients have only a single episode of depression, whereas others have recurrent episodes.
A mood disorder characterized by experiencing depressed moods or the loss of pleasure that stretch throughout the day almost every day for a least 2 weeks.