Persistent depressive disorder

Dr. Ferdous is a respected cardiologist. He has saved hundreds of hearts and cannot remember the last time his own felt light. Not sad, exactly; just grey, for as long as he can remember. At family dinners on Fridays he smiles at the right moments. He has always assumed this is simply who he is.

An illustration drawn from common experience. The person is invented; the pattern is not.

Understanding persistent depressive disorder

Persistent depressive disorder (dysthymic disorder in ICD-11) is a low mood that lasts most days for two years or more. It is often milder than a major depressive episode, but because it lasts so long, people mistake it for their personality. Many also have episodes of deeper depression on top of it. Doctors are not immune, and many wait before asking for help.

How common is persistent depressive disorder?

Depression, in all its forms, affected 322 million people worldwide in 2023, WHO estimates. That is the count for all depression; no separate figure for persistent depressive disorder is given here.

Signs and symptoms of persistent depressive disorder

• Low mood on most days for years, not weeks
• Low energy, poor concentration, low self-esteem
• Little pleasure, even in good news
• A sense that this is just “the way you are”

Treatment for persistent depressive disorder

Long-standing low mood responds to the same treatments as other depression: psychotherapy, medication, or both. UK national guidelines on depression set out options for chronic depressive symptoms: CBT, an antidepressant, or the two combined. The first step is naming it.

What getting better can look like

Recovery, for Dr. Ferdous, might be noticing colour he had stopped seeing: a joke that lands with him, too, at the Friday table.

Common questions about persistent depressive disorder

Can you be depressed for years without knowing it?

Yes. Persistent depressive disorder is a low mood that lasts most days for two years or more, often milder than a major depressive episode. Because it lasts so long, many people mistake it for their personality and never think to ask for help.

Is persistent depressive disorder treatable?

Yes. Long-standing low mood responds to the same treatments as other depression: psychotherapy, medication, or both. UK national guidelines (NICE) set out CBT, an antidepressant, or the two combined as options for chronic depressive symptoms.

When to see a psychiatrist

If you have felt low for years and assumed it is your nature, it may not be. It is worth asking.

Care here is personal: built around your history, your health and what you want to change, and reviewed with you as it goes.

If you or someone else is in immediate danger, call 999 or go to the nearest hospital emergency department.

Sources

• World Health Organization, “Mental disorders” fact sheet, September 2026
• NICE guideline NG222, Depression in adults, 2022