Psychiatrists and researchers once categorized depression using a pair of terms derived from Latin: endogenous (meaning "from within”) and exogenous ("from without"). These names were intended to indicate whether someone’s depression came from internal causes (such as genetics) or external causes (like a stressful or traumatic event). The old belief was that the distinction was necessary and that each type of depression had to be treated differently.1 Over the last few decades, however, research has not provided sufficient evidence in support of this theory. Today, depression formerly referred to as “endogenous” is known as major depressive disorder (MDD). The current philosophy is that the same types of treatment can be used for MDD whether it is "endogenous depression" However, it can still sometimes be helpful for healthcare and mental health professionals to note the concept of endogenous and exogenous causes of major depression when helping people understand the condition.
