Persistent depressive disorder (PDD), once called dysthymia, involves a long-lasting, mild yet chronic form of depression. 

It ranges in severity from mild to severe but even in its severe form, it falls short of meeting the criteria for major depression. Essentially, it entails prolonged depression with fewer symptoms compared to major depressive disorder (MDD).

Persistent Depressive Disorder vs Dysthymia

In 2013, the 5th edition of the “Diagnostic and Statistical Manual of Mental Disorders” (DSM-5) merged dysthymia and chronic major depressive disorder into a single diagnosis called “persistent depressive disorder (dysthymia),” with dysthymia in parentheses. 

This change aimed to acknowledge that there was no significant difference between “chronic” major depressive disorder and the previously distinct dysthymic disorder, as per the American Psychiatric Association’s Highlights of changes from DSM-IV-TR to DSM-5.

The most recent edition of the DSM, published in 2022, features some text adjustments (DSM-5-TR), notably the removal of “(dysthymia)” from the PDD diagnosis. The American Psychiatric Association justified this change by stating that sufficient modifications to the diagnostic criteria had been made, rendering its retention potentially “misleading and confusing.”

Persistent Depressive Disorder Symptoms

The symptoms of PDD closely resemble those of depression. However, the key distinction lies in the chronic nature of PDD, with symptoms persisting on most days for at least 2 years.

Many doctors rely on the symptoms outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) to diagnose PDD. This manual, published by the American Psychiatric Association, lists the following symptoms for PDD:

• Experiencing depression almost every day for most of the day
• Having a poor appetite or overeating
• Struggling with falling asleep or staying asleep
• Feeling low energy or fatigue
• Exhibiting low self-esteem
• Experiencing poor concentration or difficulty making decisions
• Feeling a sense of hopelessness

Causes of Persistent Depressive Disorder

The precise cause of PDD remains unclear, but several factors are thought to contribute, including:

Genetics

Research indicates that having close relatives with a history of depression can double an individual’s risk of experiencing depression themselves.

Environmental factors

Situational variables such as parental loss or separation, childhood adversity, prolonged stress, grief, major life changes, and trauma can all influence the development of PDD.

Temperament

Individuals with PDD often exhibit a higher prevalence of negative emotions. Additionally, borderline personality disorder is frequently co-diagnosed with PDD.

Brain chemistry

Imbalances in neurotransmitters like serotonin, norepinephrine, or dopamine within the brain can influence the onset of depression. Furthermore, certain environmental factors, such as prolonged stress, have the potential to modify these brain chemicals.

In many instances, these factors interact, heightening the risk of developing depression.

Diagnosis of PDD

There isn’t a laboratory test available to diagnose PDD (dysthymia) or any other form of depression. Instead, your doctor will assess your symptoms and medical history. They’ll inquire about the nature, severity, and duration of your symptoms.

Your doctor might perform a physical examination and order blood tests to rule out any underlying medical conditions contributing to your symptoms. To receive a PDD diagnosis, your doctor will need to ascertain that your symptoms aren’t better explained by substance abuse, a medical issue, or another psychological disorder.

For a persistent depressive disorder diagnosis, your doctor will compare your symptoms to the criteria outlined in the DSM-5-TR, including the necessary duration requirements.

Ultimately, your symptoms must cause significant distress or impair your ability to function normally.

Diagnosing PDD can be challenging because symptoms are so long-lasting that individuals may come to perceive them as inherent to their personality or simply a consequence of feeling stuck, rather than indicators of a treatable mental health condition.

Persistent Depressive Disorder Treatment

Treatments for PDD are similar to those for other types of depression, typically involving a combination of psychotherapy and medications for optimal effectiveness.

Psychotherapy, or talk therapy, utilizes various techniques, with cognitive behavioral therapy (CBT) and interpersonal therapy (IPT) being commonly employed:

• CBT focuses on recognizing and altering negative thought patterns underlying depression.
• IPT identifies relationship and communication issues, working towards enhancing interpersonal interactions.

Medication options for PDD include various types of antidepressants:

• Selective serotonin reuptake inhibitors (SSRIs) like Zoloft (sertraline) and Prozac (fluoxetine) elevate serotonin levels in the brain to regulate mood.
• Serotonin and norepinephrine reuptake inhibitors (SNRIs) such as Cymbalta (duloxetine) and Pristiq (desvenlafaxine) increase serotonin and norepinephrine availability.

Some individuals find relief from mild to moderate depression with herbal supplements like St. John’s Wort. However, it’s crucial to consult your doctor before taking any supplement, including St. John’s Wort, to ensure its safety and suitability for your condition.

Related: Winter Depression

Summary

Persistent depressive disorder (PDD) is a form of long-lasting depression where symptoms occur most days for at least two years. It involves feeling down, having low energy, and struggling with everyday tasks. Treatments typically include therapy and medication to help manage symptoms and improve overall well-being.

References

1. Gabbey, A. E. (2021, October 21). Persistent depressive disorder (dysthymia): What it is and more. Healthline. https://www.healthline.com/health/dysthymia 
2. Patel, R. K. (2023, June 26). Persistent depressive disorder. StatPearls [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK541052/ 
3. Schimelpfening, N. (2023, October 23). Persistent depressive disorder (previously dysthymia) symptoms and treatment. Verywell Mind. https://www.verywellmind.com/what-is-dysthymia-dysthymic-disorder-1066954