What Is Persistent Depressive Disorder (Dysthymia)

This page reflects our understanding of mental health topics as of 2026. If you are reading this at a later date, some details may no longer be current, so please verify anything important against up to date sources. If you notice anything that needs updating, we would welcome you letting us know.

If you are having thoughts of suicide, call or text 9-8-8 (Canada's Suicide Crisis Helpline) at any time. If you are in immediate danger, call 911 or go to your nearest emergency department.

Persistent depressive disorder (PDD), previously called dysthymia, is a form of depression in which low mood is present more days than not for at least two years in adults, or one year in children and teens. Symptoms may be milder than in a major depressive episode, but because they last so long, they can deeply affect relationships, work, and self-image. Many people with PDD come to believe that feeling low is simply their personality. Some also experience episodes of major depression on top of the ongoing low mood. Persistent depressive disorder is treatable, and people often feel better than they thought possible.

What Persistent Depressive Disorder Looks Like

Low, gloomy, or flat mood most of the time, for years.
Feeling empty much of the time, or unable to remember feeling truly good.
Low energy and fatigue.
Low self-esteem and a critical view of oneself.
Poor concentration and difficulty making decisions.
Feelings of hopelessness about the future.
Changes in appetite or sleep.

People with PDD often keep functioning, going to work and meeting obligations, which is why the condition is frequently overlooked. Others may see them as serious, pessimistic, or low-energy. Inside, life often feels like a grey, effortful routine. Relationships can suffer when irritability or withdrawal become habits.

Why It Happens

PDD develops from a combination of genetic vulnerability, brain chemistry, temperament, and life experiences. Childhood adversity, such as neglect, loss, or chronic stress, is associated with higher risk. Ongoing stressors, such as chronic illness, relationship difficulties, or financial strain, can maintain low mood. Because PDD often begins in childhood, adolescence, or early adulthood, people may not recognize it as a condition. Negative thinking patterns and withdrawal from rewarding activities then help keep it going.

A particularly painful aspect of PDD is that it can feel like identity rather than illness. People may say "I have always been this way." Recognizing that long-lasting low mood is a treatable condition can be a turning point.

Because the low mood of PDD is steady rather than dramatic, people often adapt their lives around it. They may lower expectations, avoid challenges, or expect little enjoyment. These adaptations make sense but can quietly shrink life over time. Treatment often involves noticing these patterns and gradually expanding what feels possible.

What It Is Not

Not a personality trait. Chronic low mood is a condition, not who you are.
Not "mild" in its impact. Symptoms may be less intense than major depression, but their duration can be very disabling.
Not the same as a major depressive episode, though both can occur together, sometimes called double depression.
Not burnout. Burnout is tied to work and eases with changes there. PDD persists across life.
Not grief. Grief follows loss and changes over time. PDD is persistent and not tied to a specific event.

How It Is Assessed and Treated

A physician, psychologist, or psychiatrist assesses PDD by exploring mood over time, symptoms, functioning, and history, and by ruling out medical causes such as thyroid problems. Treatment usually involves therapy, medication prescribed by a physician, or both. Cognitive behavioural therapy, behavioural activation, and interpersonal therapy can help shift long-standing patterns. A structured approach known as CBASP was developed specifically for chronic depression and focuses on how patterns of behaviour affect relationships. Because PDD is long-standing, treatment may take time, but many people experience significant improvement.

Getting Support at Pacific Maple Psych Centre

If low mood has been part of your life for so long that it feels normal, therapy can help you understand it and work toward feeling more alive and engaged.

Pacific Maple Psych Centre offers individual therapy for depression, including long-standing low mood, in Vancouver and virtually across British Columbia.

Book a Session

Common Questions About Persistent Depressive Disorder

What is the difference between dysthymia and persistent depressive disorder?

They refer to the same condition. Persistent depressive disorder is the current name for what was previously called dysthymia.

How long does low mood have to last for persistent depressive disorder?

In adults, low mood must be present more days than not for at least two years. In children and teens, the period is one year.

Why do so many people live with dysthymia for years without realizing it?

Symptoms are often milder and people keep functioning, so they may assume low mood is just their personality rather than a treatable condition.

What is double depression?

Double depression describes having persistent depressive disorder with episodes of major depression on top of the ongoing low mood.

Can persistent depressive disorder start in childhood?

Yes. It often begins in childhood, adolescence, or early adulthood, which is one reason people may not recognize it as a condition.

Is chronic low mood just part of who I am?

Not necessarily. Long-lasting low mood can feel like personality, but it may be persistent depressive disorder, which responds to treatment.

Is there a therapy designed specifically for chronic depression?

Yes. CBASP is a structured therapy developed for chronic depression, focusing on how patterns of behaviour affect relationships. Other approaches such as CBT and interpersonal therapy also help.

What treatment options exist for years-long low mood?

Treatment usually involves therapy, such as CBT, behavioural activation, or interpersonal therapy, and sometimes medication prescribed by a physician.

Can someone with dysthymia still work and function?

Yes. Many people with persistent depressive disorder keep working and meeting obligations, even though life feels effortful and joyless.

Can people with long-lasting depression recover?

Yes. Although treatment may take time, many people with persistent depressive disorder experience significant improvement in mood and quality of life.