Library · Disease
Major depressive disorder
Make it clearer
Major depressive disorder, also known as clinical depression, is not the same as being sad. We all feel sad or down at times, and that usually passes with time. Depression is different: it can cause severe symptoms that change how a person feels, thinks and handles everyday activities.
Where does it come from? It is thought to have no single cause. For years it was attributed mainly to disturbances in three of the brain's chemical messengers, the neurotransmitters serotonin, norepinephrine and dopamine. More recent theories look further upstream: they link it mainly to complex neural circuits, networks of interconnected neurons, which secondarily disrupt those messengers. The focus has shifted from faulty messengers to the wiring that regulates them, where what happens in the network ends up changing what flows through it. These are still theories.
Each person's background plays a part too. Family, adoption and twin studies indicate that genes influence susceptibility, and having gone through multiple adverse experiences in childhood is associated with depression later in life.
In brief
Major depressive disorder, or clinical depression, is not the kind of sadness that usually passes with time; it can cause severe symptoms that change how a person feels, thinks and handles daily activities.
It is thought to be multifactorial. It was mainly attributed to disturbances in serotonin, norepinephrine and dopamine; recent theories link it mainly to complex neural circuits, which secondarily disrupt those neurotransmitters.
Family, adoption and twin studies implicate genes in susceptibility, and multiple adverse childhood experiences are associated with later depression.
Sources (2)
- National Institute of Mental Health, National Institutes of HealthDepression, National Institute of Mental HealthPublished
- National Center for Biotechnology Information, StatPearls PublishingMajor Depressive Disorder, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated