An Overview of Persistent Depressive Disorder (Dysthymia)

Persistent depressive disorder (PDD), formerly known as dysthymia, is a mood disorder that is characterized by a milder but more chronic form of depression.

This diagnosis reflects a spectrum of severity that can range from mild to severe; however, in its most severe form, it still does not meet the criteria for major depression. Essentially, it is a prolonged state of depression with fewer symptoms than major depressive disorder (MDD).

Persistent Depressive Disorder Versus Dysthymia

In 2013, the 5th edition of the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-5) consolidated dysthymia and chronic major depressive disorder into a new diagnosis known as "persistent depressive disorder (dysthymia)," with dysthymia in parentheses. These diagnostic changes were made to reflect the fact that there was no scientifically or clinically meaningful distinction between "chronic" major depressive disorder and what was previously known as dysthymic disorder.

The latest version of the DSM was published in 2022 and has some text revisions (DSM-5-TR), including the removal of "(dysthymia)" that once followed the PDD diagnosis. The American Psychiatric Association explained that there were enough changes made to the diagnostic criteria that keeping it may be "misleading and potentially confusing."

Symptoms of Persistent Depressive Disorder

The symptoms of persistent depressive disorder (PDD) are very similar to major depressive disorder. However, there is a wider range of symptoms available on the criteria list for major depression. You need to have three of the seven symptoms for PDD as opposed to five out of nine symptoms for MDD.

The main symptom of PDD is a sad or depressed mood nearly every day. In children, the mood may manifest as irritability.

In addition to depressed/irritable mood, at least two of the following symptoms are present:

• Changes in appetite (poor appetite or overeating)
• Sleep difficulties (too little or too much sleep)
• Lack of energy or fatigue
• Poor self-esteem
• Hopelessness or feeling stuck in a rut
• Trouble concentrating or difficulty making decisions

The additional symptoms in the criteria list for MDD, (not included for PDD), are:

• Loss of interest or feeling of pleasure from most, if not all, activities
• Psychomotor symptoms (restlessness or slowed movements)
• Feeling worthless and/or experiencing excessive guilt
• Recurrent thoughts of death or feeling suicidal

Timeframe of Persistent Depressive Disorder

The symptoms of PDD are chronic, meaning that people experience a depressed mood for most days for a period of at least two years. The timeframe has been reduced to one year for children and teens. In that two-year time frame for adults, they cannot be without symptoms for more than two months at a time.

While MDD includes more symptoms, the time frame is shorter. A diagnosis of major depression requires symptoms that last for a period of at least two weeks; however, it often lasts several months. The majority (80%) of people have fully recovered within one year.

People with MDD may completely recover and never experience an episode of major depression again. However, one episode of MDD is a risk factor for developing PDD and/or recurrent major depression episodes down the road.

Age of Onset

Another distinction is that PDD may have an earlier onset than MDD, with symptoms first appearing during the childhood, teen, or young adult years. MDD is more likely to occur after puberty, peaking in early adulthood, but can occur at any time throughout adulthood.

Causes of Persistent Depressive Disorder

Like other forms of depression, the exact cause of PDD is not known, but there are a number of factors that are believed to play a role, including:

• Temperament: People with PDD tend to have a higher degree of negative emotions. Borderline personality disorder is often diagnosed alongside PDD.
• Environmental factors: Situational variables such as parental loss or separation, childhood adversity, prolonged stress, grief, major life changes, and trauma.
• Genetics: Research suggests that having close family members with a history of depression doubles a person's risk of developing depression.
• Brain chemistry: The balance of neurotransmitters (serotonin, norepinephrine, or dopamine) in the brain can play a role in the onset of depression. Some environmental factors, such as prolonged stress, can actually alter these brain chemicals.

In many cases, these factors interact to increase the risk of developing depression.

Confirming a Diagnosis of PDD

There is no laboratory test for diagnosing dysthymia or any other form of depression. If you are experiencing symptoms of depression, your doctor will evaluate your symptoms and medical history. You will be asked questions about the nature, severity, and duration of your symptoms.

Your doctor may conduct a physical and order bloodwork to rule out any medical illnesses that might be causing your symptoms. To receive a diagnosis of PDD, your doctor must determine that your symptoms could not be better accounted for by drug or alcohol use, a medical condition, or another psychological disorder.

In order to be diagnosed with persistent depressive disorder, your doctor will check to see if your symptoms meet the diagnostic criteria outlined in the DSM-5-TR, which includes duration requirements as mentioned previously.

Lastly, the symptoms must result in significant distress or impairment of normal functioning.

PDD is sometimes difficult to diagnose because symptoms are so long-lasting that many people begin to believe that their symptoms are simply a part of their personality or "who they are" rather than a result of a treatable condition. Or they may attribute these feelings to just being stuck in a rut rather than as symptoms of a mental health condition.

Treatment for Persistent Depressive Disorder

The treatments for PDD are similar to treatments for other forms of depression. Generally, a combination of psychotherapy and medications is the most effective.

Talk Therapy

Psychotherapy may involve a range of different techniques, but two that are often used are cognitive behavioral therapy (CBT) and interpersonal therapy (IPT).

• CBT: This type of therapy focuses on learning to identify and change the underlying negative thought patterns that often contribute to feelings of depression.
• IPT: This therapy is similar to CBT but focuses on identifying problems in relationships and communication and then finding ways to make improvements in how you relate to and interact with others.

Medication

There are a number of different types of antidepressants that may be prescribed to treat PDD, including:

• Selective serotonin reuptake inhibitors (SSRIs): These medications include sertraline Zoloft (sertraline) and Prozac (fluoxetine). SSRIs work by increasing the availability of serotonin levels in the brain, which can help improve and regulate mood.
• Serotonin and norepinephrine reuptake inhibitors (SNRIs): These medications include Cymbalta (duloxetine) and Pristiq (desvenlafaxine). SNRIs work by increasing the availability of serotonin and norepinephrine in the brain.

Herbal supplements such as St. John's Wort, have been reported to be helpful in cases of mild to moderate depression. While St. John's Wort and other natural treatment options appear to work for some people with depression, it's important that you never take any supplement without first talking to your doctor.

Coping With Persistent Depressive Disorder

There are a number of different things that people can do to help cope with persistent depression. Because this type of depression is chronic, incorporating lifestyle changes and self-care with your medical treatments can be helpful. Some things that you can do that will complement therapy and medication:

• Avoid alcohol and other substances.
• Create daily routines that help structure and balance your day.
• Eat a healthy diet.
• Establish a consistent sleep schedule.
• Get regular exercise several times each week.
• Leave the house and make plans with friends.
• Practice stress management techniques such as journaling, taking a walk, and deep breathing.

It can be challenging to do many of these things when you are feeling depressed. While it may be a struggle, remember that you don't need to do it all perfectly. Even small changes can make a difference in your mood and mindset. For example, you might start out by making small goals and then gradually build on them over time.

Even very mild symptoms of depression can disrupt your ability to function and enjoy life, particularly when these symptoms are long-lasting. Fortunately, there are effective treatments available for persistent depressive disorder that can make a major difference in your health and well-being. Talk to your doctor about how you are feeling to explore the treatment options that are right for you.