There's no single known cause of depression, but we do know biological and social factors play a role. Medical research has shown that depression may be related to a chemical imbalance of serotonin, one of the substances called neurotransmitters that transport signals between nerve cells in the brain. Certain life difficulties, such as loss of a loved one, a divorce, stress at work or a series of disappointments, can contribute to depression.
Help is available.
Because depression involves both biological and emotional factors, doctors often combine medication and psychotherapy.