Menu Healthy Lifestyle Diseases & Conditions First Aid Symptoms Tests & Procedures Videos Definitions FAQs Major depressionUpdated: 2017-06-13OverviewMajor depression is a mood disorder. Causes range from brain chemistry to life events.SymptomsIt causes a persistent feeling of sadness or loss of interest that can lead to emotional and physical conditions.TreatmentsMany drugs treat depression. Talk therapy also can be helpful. © 1998-2022 Mayo Foundation for Medical Education and Research(MFMER). All rights reserved. Terms of Use