What is persistent depressive disorder?

Persistent depressive disorder (PPD; sometimes called dysthymia) is a chronic, long-lasting form of depression. It lasts longer than major depression—in some cases, for years at a time. Many people^[1] with PDD feel as though they have been depressed for as long as they can remember. Their depressive state might fluctuate, sometimes being mild, and at other times making daily life feel impossible. It is common for people with PPD to experience a lack of energy, heightened irritability, and low motivation. Unintended weight loss can also occur. When left untreated, these symptoms can lead to other mental disorders, such as anxiety and major depression.

How common is persistent depressive disorder?

Persistent depressive disorder is about as common^[2] as major depression. Roughly 6% of people in the United States have experienced at least one episode of PDD, with 3% of these episodes occurring within the last year. About one-third of all patients who are in psychotherapy of some kind are dealing with depressive disorder. As is with major depression, PDD is more common in women than in men. The condition usually comes on earlier in life, and almost half of patients with PDD develop major depression^[3].

What causes persistent depressive disorder?

The exact cause of some mental disorders, including persistent depressive disorder, is unknown. Like major depressive disorder, persistent depressive disorder likely results from a combination of factors^[4], including:

• Brain chemistry: Naturally occurring chemicals found in the brain called neurotransmitters are known to play a role in depression. Recent research indicates that changes in the effects and function of neurotransmitters, as well as how they interact with neural circuits (which help maintain mood stability), may play a considerable role in depression and how it is treated.
• Genetics: While research has not yet determined why, PDD seems to be more common in individuals whose blood relatives (such as parents or siblings) also have the condition.
• Life events: As is the case with major depressive disorder, traumatic events—such as the death of a loved one, work or financial problems, or high levels of stress—can trigger PDD in some individuals.

Risk factors for persistent depressive disorder

Some factors may increase your risk of developing PDD, including:

• Having a history of mental health conditions, such as anxiety or bipolar disorder
• Family history: Those who have a first-degree family member with PDD are more likely than others to develop the condition too.
• Stressful or traumatic life events: Whether it’s a big break-up, the passing of a loved one, or severe financial loss, unexpected stress can weigh on you heavily. This can progress into PDD, so it is important to keep tabs on yourself during these times.
• Pre-existing health conditions: Both heart disease^[5] and diabetes^[6] can be precursors to developing PDD.
• Physical trauma to the brain, such as a concussion: Events like this can shift the chemical balance of your brain or bruise it, which can catalyze the development of PDD.

Persistent depressive disorder symptoms

It’s normal for everyone to feel sad or dejected at times. However, if you feel lost, hopeless, or depressed for a period of time without improvement, it may be a good idea to talk to your healthcare provider about the possibility of persistent depressive disorder. Some common signs and symptoms^[7] of persistent depressive disorder include:

• Feeling sad, empty, or generally down
• Poor appetite or overeating
• General loss of interest in daily life and activities; decreased interest in or spending less time on hobbies
• Trouble concentrating or making decisions
• Insomnia^[8] or difficulty sleeping
• Extreme fatigue or feeling of having consistently low energy
• Feeling incapable, self-critical, and/or hopeless; the things that used to cheer you up or bring you joy no longer seem to do so.
• Poor concentration or having a hard time focusing; decreased productivity
• Self-isolation
• Feelings of guilt, shame, or worry about the past
• Abnormally high irritability or anger over things that seem trivial and small (Irritability is the primary symptom of PDD in children, along with depressed mood)

If you or a loved one is exhibiting one or more of one of these symptoms, talk to your healthcare provider. There is no shame in experiencing depression. Your provider can help determine the right diagnosis and treatment plan (or refer you to a specialist who can do so).

Complications from persistent depressive disorder

When left untreated, persistent depressive disorder can cause a number of physical or mental health complications^[9]. These may include:

• Reduced quality of life: The signs and symptoms of PDD can make it difficult to function in daily life (including responsibilities like work or school) as normal. It can also strain or negatively affect personal relationships.
• Major depression, anxiety disorders, and other mood disorders
• Self-Harm: The thoughts of depression that can creep up as a result of PPD are one of its most serious complications, and it is important to keep an eye on this.
• Drug or alcohol dependence or abuse
• Suicidal thoughts or actions: It is incredibly important that you talk to a loved one or a healthcare provider if you have thoughts or feelings of suicide^[10]. You can call the National Suicide Prevention Lifeline at 1-800-273-8255.
• Severe weight gain or loss
• Drowsiness^[11]: This is generally caused by the lack of sleep and insomnia that can be characteristic of PDD.