A SERIOUS, TREATABLE, VERY COMMON MEDICAL ILLNESS.
Typified by sadness, sleeping too little or too much, eating too little or too much, and loss of interest in usually pleasurable activities.
Disease responsible for the most years lived with disability, according to the World Health Organization.
Divided into unipolar depression (only depressive episodes) and bipolar disorder (depressive episodes alternating with manic periods of elevated mood).
Unipolar depression usually treated best with antidepressant medication plus psychotherapy.
Bipolar disorder treatment usually includes mood stabilizer.