major depressive disorder

noun

: a serious mood disorder involving one or more episodes of intense psychological depression or loss of interest or pleasure that lasts two or more weeks and is accompanied by irritability, fatigue, poor concentration, sleep disturbances, weight gain or loss, feelings of worthlessness or guilt, and sometimes suicidal tendencies : clinical depression, major depression

About 18 million Americans are diagnosed with a major depressive disorder each year.

—David Schwab

The most serious form of depression is major depressive disorder, characterized by depressed mood, loss of interest or pleasure, changes in appetite, increased or decreased sleep, increased or decreased motor activity, fatigue, feelings of worthlessness or guilt, difficulty concentrating and, for some people, recurrent thoughts of death or suicide.

—Sandi Lloyd

—abbreviation MDD

Examples of major depressive disorder in a Sentence

Recent Examples on the Web

Mood disorders Patients with major depressive disorder or other mood disorders often find their way to the Depression Clinical and Research Program at Massachusetts General Hospital, where Paolo Cassano, a professor of psychiatry at Harvard Medical School, is director. —The Washington Post, San Diego Union-Tribune, 11 Feb. 2025

Her long-term disability claim was denied, a result of a reviewer deeming her mental health conditions ― PTSD, major depressive disorder and severe social anxiety disorder ― pre-existing. —Natalie Eilbert, Journal Sentinel, 19 Dec. 2024

His research found that those who walked more than 8,200 steps a day lowered their risk of obesity, sleep apnea, reflux disease and major depressive disorder. —Ronnie Cohen, NPR, 5 Jan. 2025

In the United States, Pristiq is approved to treat major depressive disorder. —Jessica Swirble, Verywell Health, 17 Jan. 2025

Word History

First Known Use

1977, in the meaning defined above

Medical Definition

major depressive disorder

noun

: a serious mood disorder involving one or more episodes of intense psychological depression or loss of interest or pleasure that lasts two or more weeks and is accompanied by irritability, fatigue, poor concentration, sleep disturbances, weight gain or loss, feelings of worthlessness or guilt, and sometimes suicidal tendencies : clinical depression, major depression

The diagnosis of both major depressive disorder and subsyndromal symptoms is complicated by difficulties that elderly patients may have in recognizing or describing depressive symptoms.

—Lawrence M. Martin et al., The John Hopkins White Papers

—abbreviation MDD