Low for Years, Not Weeks: Persistent Depressive Disorder

Some people can name the week their depression began. Others cannot remember a time when life felt bright. If you have been running on low for so long that it seems like part of your personality, it may be worth asking whether a treatable condition has been there all along.

A long, low form of depression

MedlinePlus, from the National Library of Medicine, describes persistent depressive disorder (PDD) as a chronic form of depression in which mood is regularly low, and notes it used to be called dysthymia. The National Institute of Mental Health (NIMH) puts it this way: the symptoms are less severe than in a major depressive episode but last much longer, usually for at least 2 years. Persistent depressive disorder is the DSM-5-TR name, and a qualified clinician makes the diagnosis.

What it can feel like

MedlinePlus describes a low, dark or sad mood on most days, along with two or more of these nearly all the time:

• Hopelessness
• Sleeping too little or too much
• Low energy or tiredness
• Low self-esteem
• Poor appetite or overeating
• Trouble concentrating

People with PDD often hold a negative view of themselves, the future, other people and life events, MedlinePlus adds, and problems can seem hard to solve. For adults, the low mood has lasted at least 2 years.

How it differs from a major depressive episode

NIMH explains that depression in the usual sense is diagnosed when symptoms are present most of the day, nearly every day, for at least two weeks, and one of them is a depressed mood or a loss of interest or pleasure in most activities. PDD trades some of that intensity for length. The two can overlap: MedlinePlus says most people with PDD will also have at least one episode of major depression.

Why it can go untreated

When a low mood has been around for years, it can stop feeling like a symptom at all. People keep working, parenting and showing up, so friends and family may not notice anything is wrong. The hopeless outlook that comes with PDD can also make asking for help feel pointless. NIMH says that people with only a few symptoms may benefit from treatment, so you do not have to be at your worst to deserve an evaluation.

Who is more likely to have it

MedlinePlus says the exact cause is unknown, that PDD can run in families and that it occurs more often in women. NIMH describes genetic, biological, environmental and psychological factors in depression, and notes that it often occurs alongside chronic illnesses such as diabetes, heart disease and chronic pain.

Checking for other causes

NIMH says some medical conditions, such as viruses or thyroid disorders, can cause the same symptoms as depression, and a provider can check for them with a physical exam, an interview and lab tests. If you need lab work, it can be done at a lab of your choice near you.

What treatment involves

MedlinePlus names cognitive behavioral therapy (CBT) and insight-oriented therapy, along with support groups. NIMH describes CBT and interpersonal therapy, and notes that talk therapy can happen in person or virtually. Medication, when indicated, is one more option, and whether to use it is a decision you and your provider share. MedlinePlus cautions that medicine for PDD may work less well and more slowly than it does for major depression, and that it should never be stopped without talking with your provider. Read why changes should be made with your provider.

MedlinePlus calls PDD a chronic condition that can last for years. Many people get completely well, while others keep some symptoms even with treatment.

Small steps that help alongside treatment

• Keep going with treatment, and expect improvement to come gradually.
• Do something you used to enjoy, even when you do not feel like it.
• Move a little every day. NIMH says just 30 minutes a day of walking can boost your mood.
• Keep a regular sleep schedule and regular meals.
• Stay in touch with people you trust, and put big life decisions on hold until you feel better.
• Avoid alcohol, nicotine and drugs.

The risk that needs attention

MedlinePlus notes that PDD raises the risk of suicide. Signs such as talk of death, giving belongings away or pulling back from others need help right away.

Care at Hope Behavioral Medicine

We evaluate and treat depression, including persistent depressive disorder, in West Ashley and by secure video anywhere in South Carolina through our telehealth depression care. A first visit looks at how long the low mood has been with you and what you have already tried. Request an appointment.

Sources: MedlinePlus, Persistent Depressive Disorder (reviewed July 2026); NIMH, Depression (revised 2024); American Psychiatric Association, DSM-5-TR (persistent depressive disorder).

This article is general information, not medical advice, and does not create a patient–provider relationship. Every situation is different, so see a provider who can evaluate yours and develop a plan of care. Any medication discussed here may not be right for you: the right choice depends on your diagnoses, other health conditions and current medicines, so take medication only as directed by the provider managing your care. If you are ever in doubt about an emergency, call 911 or go to the nearest emergency room.