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    Depression

    抑郁症

    Clinical diagnosis
    Also called
    major depressive disorder, MDD, major depression, depressive disorder, single episode depressive disorder, recurrent depressive disorder

    What is depression?

    Depression is a common mental disorder: for at least two weeks a person feels low, or loses interest in things they usually enjoy, most of the day, nearly every day. Other symptoms follow, such as poor concentration, low self-worth or changes in sleep, appetite and energy, and daily life is clearly disrupted.[1][2]

    ICD-11: 10 symptoms in three clusters

    Not the same as

    Severity and treatment

    Schematic, not a self-test.

    Select a card or bar for details.
    Schematic: ICD-11 sorts the 10 symptoms of a depressive episode into three clusters. The threshold is at least five at once for two weeks or more, at least one from the mood cluster, with clear effects on daily life. On the right, two things often confused with depression; below, how severity relates to treatment. Select a part for details. Select a part for details
    Schematic: ICD-11 sorts the 10 symptoms of a depressive episode into three clusters. The threshold is at least five at once for two weeks or more, at least one from the mood cluster, with clear effects on daily life. On the right, two things often confused with depression; below, how severity relates to treatment. Select a part for details. Save as image (PNG)

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    Key points

    • ICD-11 lists 10 symptoms in three clusters. A depressive episode needs at least five, lasting two weeks or more, including low mood or markedly reduced interest.[1]
    • Grief after a death can also bring intense sadness, but the pain tends to come in waves mixed with good memories, and self-esteem usually holds. In depression, worthlessness is common.[2]
    • WHO estimates that 5.2% of adults worldwide had depression in 2023, women about 1.5 times as often as men. Even in high-income countries only about a third of them get treatment.[3]
    • Psychological treatments such as behavioral activation and CBT come first; antidepressants can be added in moderate or severe depression, not mild.[3] For more severe depression NICE ranks CBT plus medication first.[4]

    An example

    After his project is cancelled, Jay wakes before dawn for three weeks running and skips the weekly basketball game he used to love. He keeps saying he can’t do anything right and drifts off in meetings. Lin notices and goes with him to see a psychiatrist, who will assess what is going on and whether he needs treatment.

    Misreadings and limits

    Online depression quizzes cannot diagnose anyone. Diagnosis takes a full professional assessment that rules out medical causes such as an underactive thyroid, and the effects of drugs.[1][2] Low mood that lasts two weeks or more and affects daily life is a reason to see a doctor soon; thoughts of self-harm or suicide call for professional help right away.[3]

    If you need help now

    If you’re struggling to cope or having thoughts of harming yourself:

    If you’re in immediate danger, call your local emergency number.

    Psyfield is not a crisis service. Numbers checked October 2026.

    Sources

    1. 1 World Health Organization (2025). Mood disorders: Depressive episode; 6A70 Single episode depressive disorder; 6A71 Recurrent depressive disorder. ICD-11 for mortality and morbidity statistics (2025-01 release). View source
    2. 2 American Psychiatric Association (2024). What is depression?. Psychiatry.org (physician review April 2024). View source
    3. 3 World Health Organization (2026). Depressive disorder (depression). WHO fact sheet (September 11, 2026). View source
    4. 4 National Institute for Health and Care Excellence (2022). Depression in adults: Treatment and management (NG222). NICE guideline (published June 29, 2022). View source

    Last checked against sources: October 28, 2026