Major Depressive Disorder: Comprehensive Overview of Causes, Treatment, and Outcomes
What is major depressive disorder?
Major depressive disorder (MDD) is a complex mental health condition characterized by persistent depressed mood, loss of interest in activities, and physical and cognitive symptoms that significantly impair daily functioning. A comprehensive 2023 Nature Reviews Disease Primers overview reveals that MDD affects hundreds of millions of people worldwide and is one of the leading causes of disability globally.
MDD develops through complex interactions between genetic, environmental, psychological, and biological factors rather than any single cause. The disorder involves multiple brain systems including neurotransmitters, neuroendocrine pathways, inflammation, and neuroplasticity mechanisms working together.