What is PDD?

Persistent depressive disorder (PDD), also known as dysthymia, is a chronic depressive mood disorder involving a depressed spectrum characterized by a depressed mood present most of the time during at least two years. While the condition is reported to affect up to 6% of Canadians over the age of 18, not much is known about the disorder and it often goes undetected.

PDD is a disorder (sometimes hereditary) presenting symptoms that are similar to those of major depressive disorder and that manifest with various levels of severity (mild, moderate and severe). Most people suffering from PDD have experienced at least one major depressive episode in their lifetime. When compared with major depression, PDD symptoms are fewer and less severe, but last for a longer period of time (sometimes from 20 to 30 years).

While people suffering from PDD are generally higher-functioning than people with major depression, interpersonal and social relationships can be challenging. A loss of pleasure or interest in activities they previously enjoyed can cause PDD sufferers to withdraw from their social circles.

People with PDD usually function adequately, but not optimally. Concentration and decision making can be difficult, and patients may exhibit low energy and an anxious, irritable mood. Persistent feelings of sadness, guilt, desperation and worthlessness can lead sufferers to believe features of the disease are personality traits, which prevents them from feeling relaxed and happy.

Persistent feelings of sadness, guilt, desperation and worthlessness can lead sufferers to believe features of the disease are personality traits, which prevents them from feeling relaxed and happy.


The primary symptom of PDD is feeling depressed or low most of the time for at least two years.

People suffering from PDD may display several of the following symptoms:

  • A negative view of themselves, the future, life events and other people
  • Feeling discouraged when faced with problems and struggling to resolve them
  • Loss of appetite or hyperphagia (compulsive overeating)
  • Insomnia or hypersomnia
  • Fatigue or loss of energy
  • Low self-esteem
  • Difficulty concentrating or making decisions
  • A feeling of desperation

PDD in children is often associated with:

  • An irritable, sullen or depressed mood (the mood may be irritable rather than depressed in children and adolescents, and the occurrence must last at least one year)
  • Poor academic performance
  • Insufficient social interactions or limited social skills
  • Low self-confidence
  • A pessimistic outlook

In adults, the impact of persistent depressive disorder on quality of life can be just as upsetting as it is in major depression. Among other things, PDD escalates the risk of psychiatric comorbidity—particularly anxiety and substance abuse—and its manifestation before age 21 is strongly associated with a variety of personality disorders:

  • Borderline personality disorder
  • Narcissistic personality disorder
  • Antisocial personality disorder
  • Avoidant personality disorder
  • Dependent personality disorder
  • Obsessive-compulsive disorder

Risk factors

Although the exact cause of persistent depressive disorder is unknown, there appears to be a familial predisposition (genetic and/or learned); the disorder is also associated with psychosocial stressors (environmental factors), especially in the absence of appropriate or sufficient coping strategies (behavioural factors).

While anyone can show symptoms of PDD (young people and adults), the disorder is diagnosed two to three times more often in women than in men. The condition is considered early-onset when it manifests before age 21, and late-onset after age 21.

A relatively small proportion of people suffering from PDD seek treatment. In fact, a study carried out on a fairly large number of PDD patients showed that only 41% had received drug therapy and only 56% had received psychotherapy. One possible explanation for this is the insidious onset of symptoms and their relative weakness, along with denial or lack of self-awareness in PDD sufferers.


Several tools are available to combat or alleviate symptoms associated with PDD.

A person suspecting PDD should always begin by consulting a health professional. The specialist can establish a diagnosis and suggest treatment options.

Medication can often be an effective treatment option for PDD, although results may be less pronounced and take effect more slowly when compared with major depression. People suffering from PDD frequently take an antidepressant that helps maintain energy levels and curb intensely depressive moods.

Psychotherapy can also help people suffering from PDD by providing an appropriate setting to discuss and learn to manage their emotions and thoughts.

Here are a few recognized psychotherapy approaches:

  • Cognitive-behavioural therapy (CBT) helps patients identify their symptoms and aggravating factors, and learn problem-solving skills.
  • Insight-oriented therapy encourages PDD sufferers to understand the root causes of their depressive thoughts and feelings.
  • Support groups bring together people dealing with similar issues and can serve as an effective management strategy.

The following measures can also alleviate PDD symptoms:

  • Getting enough sleep
  • Developing healthy eating habits
  • Using medications as directed (secondary effects should be discussed with a health professional)
  • Learning to recognize the worsening of symptoms and preparing a response strategy
  • Exercising regularly
  • Seeking out enjoyable activities
  • Sharing your feeling with someone you trust
  • Surrounding yourself with loving, positive people
  • Avoiding alcohol and illicit drug use

It should be noted that a three-pronged approach combining the methods mentioned above—medication, psychotherapy and the adoption of a healthy lifestyle—is the recommended treatment option for PDD.


Are you currently or do you think you might be suffering from PDD? Do you know someone who might be suffering from PDD? There are many resources available to help.

Healthcare professionals are equipped to support PDD sufferers and their loved ones, and should always be a first line of defence. It is possible to meet a specialist at a nearby clinic for mental-health-related support and information, especially through the Guichet d’accès en santé mentale of your CLSC.

The links below contain information on accessing a family doctor or psychologist:

There are also several organizations that offer excellent support services to people suffering from PDD

  • Revivre supports people suffering from anxiety, depression and bipolar disorder. Aiming to provide people with the tools to manage their own health, the organization guides them through the gradual process of improving their daily quality of life.
  • Tel-Aide is a free call-in listening centre. It is anonymous, confidential and available to anyone who needs to talk through problems or who feels suicidal.

You are not alone