- Biologic- an imbalance of certain neurotransmitters- the chemicals in the brain that transmit messages between nerves cells-is believed to be key to depression.
- Heredity - Individuals with major depression in their immediate family are up to three times more likely to have the disorder themselves.
- External stressors and significant life changes - such as chronic medical problems, death of a loved one, divorce or estrangement, miscarriage, or loss of a job, also can result in a form of depression know as adjustment disorder.