How long do symptoms have to last for each diagnosis?

Major depression requires symptoms most of the day, nearly every day, for at least 2 weeks. Persistent depressive disorder (dysthymia) requires a depressed mood on most days for at least 2 years in adults, or 1 year in children and teens, with no symptom-free stretch longer than 2 months.

Can you have dysthymia and major depression at the same time?

Yes. When a major depressive episode occurs on top of persistent depressive disorder, clinicians call it double depression. In that case both diagnoses apply. Most people with persistent depressive disorder have at least one major depressive episode at some point.

Is dysthymia less serious than major depression?

The day-to-day symptoms are usually less intense, but the condition is not mild. In the National Comorbidity Survey Replication, 49.7% of adults with past-year persistent depressive disorder had serious impairment. The long duration means the total burden on work, school, and relationships can match or exceed a single major depressive episode.

Is persistent depressive disorder the same thing as dysthymia?

Yes. The DSM-5 replaced the older term dysthymia (and chronic major depression) with persistent depressive disorder. Many clinicians and older resources still use the word dysthymia, but the current diagnostic label is persistent depressive disorder.

Dysthymia vs. Major Depression: What Is the Difference?

Q: Do antidepressants work for dysthymia?

Often, yes. MedlinePlus notes that medicines are frequently effective for persistent depressive disorder, though they sometimes work less well than in major depression and may take longer. Antidepressants typically need 4 to 8 weeks to show an effect. Combining medication with psychotherapy is linked to higher response rates.

The short answer: The main difference is duration and intensity. Major depression is an episode: at least five symptoms, most of the day, nearly every day, for at least 2 weeks. Dysthymia, now called persistent depressive disorder (PDD), is chronic: a depressed mood on most days for at least 2 years, with fewer symptoms required. The two can occur together, which clinicians call double depression, and both respond to treatment.

What is dysthymia (persistent depressive disorder)?

Dysthymia is the older name. The DSM-5 folded it, along with chronic major depression, into one diagnosis: persistent depressive disorder. Per the StatPearls review of PDD, the diagnosis requires a depressed mood most of the day, on more days than not, for at least 2 years in adults. Children and teens need only 1 year, and their mood can be irritable rather than sad.

Along with the low mood, a person needs at least 2 of these 6 symptoms: poor appetite or overeating, insomnia or sleeping too much, low energy, low self-esteem, poor concentration, and hopelessness. One rule does a lot of work: during those 2 years, the person has never been symptom-free for more than 2 months at a time. That is what makes it "persistent." MedlinePlus describes it as a chronic depression in which moods are regularly low, and notes it runs in families and occurs more often in women.

Because the symptoms are chronic but often less intense, many people with PDD keep working and socializing while feeling gray for years. That pattern overlaps with what people describe as high-functioning depression, and many people with PDD assume this is simply their personality rather than a treatable condition.

What counts as major depression?

Major depressive disorder (MDD) is defined by an episode, not a baseline. Per the StatPearls review of MDD, a diagnosis requires at least 5 of 9 symptoms, and at least one of them must be depressed mood or anhedonia (loss of interest or pleasure). The other symptoms are guilt or worthlessness, low energy, poor concentration, appetite change, psychomotor slowing or agitation, sleep disturbance, and thoughts of death or suicide. The symptoms must cause real social or occupational impairment.

The NIMH depression publication sets the time bar: "To be diagnosed with depression, a person must have symptoms most of the day, nearly every day, for at least 2 weeks." An episode can resolve and return; our post on whether depression goes away covers relapse patterns in detail.

How do the diagnostic criteria compare side by side?

Duration: MDD requires 2 weeks. PDD requires 2 years in adults (1 year in children and teens).
Symptom count: MDD requires 5 of 9 symptoms. PDD requires depressed mood plus 2 of 6 symptoms.
Core symptom: MDD can be diagnosed with anhedonia and no sad mood. PDD requires the depressed mood itself.
Course: MDD is episodic, with possible full recovery between episodes. PDD allows no symptom-free stretch longer than 2 months.
Typical intensity: MDD episodes are usually more severe day to day. PDD is lower grade but relentless.

Some symptoms of PDD never appear in the MDD list, and the reverse is also true. Suicidal thoughts and psychomotor changes belong to the MDD criteria; low self-esteem and hopelessness are named in the PDD list. In practice the pictures blur, which is one reason the DSM-5 merged chronic forms under one label.

Which one is more common?

Major depression, by a wide margin. Per NIMH statistics from the 2021 National Survey on Drug Use and Health, an estimated 21.0 million U.S. adults, or 8.3%, had at least one major depressive episode in the past year. Prevalence was 10.3% in women and 6.2% in men, and highest, at 18.6%, in adults aged 18 to 25. Only 61.0% of adults with an episode received treatment.

Persistent depressive disorder is less common in any single year. Per NIMH statistics from the National Comorbidity Survey Replication (2001-2003), an estimated 1.5% of U.S. adults had PDD in the past year (1.9% of women, 1.0% of men), and about 2.5% experience it at some point in life. The gap partly reflects definitions: a 2-year condition simply accumulates fewer new cases per year than a 2-week one.

Is dysthymia really the "milder" one?

Symptom by symptom, usually yes. In total burden, no. In the same NIMH data, 49.7% of adults with past-year PDD had serious impairment on the Sheehan Disability Scale, and another 32.1% had moderate impairment. A condition that limits work, school, and relationships on most days for years is not mild.

Chronicity carries its own risks. People adapt to feeling low, stop noticing it as abnormal, and wait longer to seek care. Anxiety disorders and other conditions frequently travel with chronic depression; if worry and dread dominate your picture, anxiety.md covers how the two overlap and get told apart.

What is double depression?

Double depression means a major depressive episode lands on top of persistent depressive disorder. The StatPearls review notes that major depressive episodes may occur during PDD, and that when full MDD criteria are met, both diagnoses are given. MedlinePlus adds that most people with PDD will have a major depressive episode at some point.

The pattern matters clinically. A person in double depression who gets treated may improve back to their dysthymic baseline and call that "recovered," when the chronic layer still needs treatment. Telling your clinician how you felt between episodes, not just during the worst weeks, changes the diagnosis and the plan.

Does treatment differ between the two?

The tools are the same: psychotherapy, antidepressant medication, or both. The NIMH names cognitive behavioral therapy (CBT) and interpersonal therapy (IPT) as evidence-based psychotherapies, and notes that antidepressants usually take 4 to 8 weeks to work, with sleep, appetite, and concentration often improving before mood lifts.

Two PDD-specific points are worth knowing. MedlinePlus notes that medicines are often effective for PDD but sometimes work less well than in major depression and may take longer. And the StatPearls review reports that combining medication with psychotherapy is linked to higher response rates and better functioning than either alone, which makes combination treatment a common choice for chronic depression. For a broader comparison of what works, see our guide to depression treatment options compared.

The bottom line

Major depression is a 2-week-minimum episode with at least 5 symptoms. Dysthymia, now persistent depressive disorder, is a 2-year-minimum chronic state with fewer but unrelenting symptoms. Major depression is far more common in any given year (8.3% of U.S. adults vs. 1.5%), but PDD is seriously impairing for about half the people who have it. The two often combine as double depression. Both are treatable with CBT, IPT, and antidepressants, and chronic depression responds best to medication and therapy together. If your low mood has lasted years, that is a diagnosis, not a personality.

Last updated: September 2026. This article is for informational purposes only and does not constitute medical advice. Talk to your clinician about diagnosis and treatment, and seek care promptly if you have thoughts of harming yourself.