Persistent Depressive Disorder Fast Facts

Persistent depressive disorder (PDD) is a mood disorder that causes relatively minor but long-lasting depressed moods.

The disorder is sometimes called dysthymia or dysthymic disorder.

PDD is similar to major depressive disorder, but its symptoms are typically milder.

As many as 3% of Americans experience PDD at some time.

PDD is more common in people who have close relatives with the disorder.

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As many as 3% of Americans experience PDD at some time.

What is Persistent Depressive Disorder?

Persistent depressive disorder (PDD) is a mental health-related issue characterized by near-constant feelings of sadness or low mood. People with the disorder experience depressed moods most of the time for a period of at least two years.

PDD is sometimes called dysthymia or dysthymic disorder. PDD symptoms may resemble those of major depression, but PDD symptoms are generally milder. However, PDD symptoms may be more persistent, and a person with the disorder can experience symptoms most of the time with few or no periods of relief.

Symptoms of PDD

Symptoms of PDD can include:

  • Sadness
  • Anxiety
  • Hopelessness
  • Low self-esteem
  • Guilt
  • Irritability
  • Fatigue or general lack of energy
  • Problems with concentration or decision-making
  • Loss of interest in activities you once found pleasurable
  • Changes in appetite or weight
  • Sleep disruptions

What Causes Persistent Depressive Disorder?

Scientists have not yet determined what causes PDD. The underlying causes of PDD may be similar to or the same as major depression. Doctors don’t know precisely what those causes are, but they have identified several risk factors that increase the likelihood of an individual developing depression.

  • Genetic Predisposition. People with a family history of depression are three times more likely to be diagnosed with major depression than those with no family history of the disorder. Researchers have begun to identify genes that may play a role in developing depression. Still, the exact genetic mechanism that makes some people more prone to developing the disorder has not yet been pinpointed.
  • Biological Causes. Some hormonal imbalances, such as the abnormal cortisol levels experienced by sufferers of Cushing’s Disease, have been linked to depression.
  • Environmental Risk Factors. While poor sleep habits are a common symptom of depression, some suggest that lack of adequate sleep may also be a risk factor for developing depression.
  • Substance Abuse. Excessive alcohol consumption or the abuse of drugs or other substances often occurs with depression.
  • Other Illnesses. Chronic severe illnesses such as Parkinson’s disease, diabetes, heart disease, obesity, or chronic pain are often accompanied by depression. The depressive moods may be caused by the effects of the disease on the patient’s life or caused by biological changes that occur in the patient’s body as part of the disease.
  • Social Risk Factors. Major life events, such as divorce, unemployment, or losing a loved one, often trigger depressive symptoms.

Is Persistent Depressive Disorder Hereditary?

Researchers have not identified a direct genetic link to PDD and other kinds of depression, but many scientists suspect there is a genetic component to risk for the disorders. People who have a parent or sibling with PDD are more likely to have PDD themselves, and the condition has been observed to run in families. This suggests that genetics play some role in developing depression, although it’s likely that the disorders are triggered by a combination of genetic and environmental factors.

How Is Persistent Depressive Disorder Detected?

By definition, PDD involves a depressed mood that lasts for an extended time. Because of this, it’s challenging to spot the beginning of the disorder. It’s normal to feel sad or lack energy sometimes, but a persistent low or dark mood that won’t go away could be a sign of PDD or major depression.

Some possible early warning signs of depression include:

  • Problems with concentration
  • Sleeping too much or too little
  • Changes in appetite
  • Irritability or mood swings

How Is Persistent Depressive Disorder Diagnosed?

Diagnosis of persistent depressive disorder begins by ruling out medical problems that may be causing symptoms. After these exams, if the doctor suspects that PDD or another mental disorder is the cause of the symptoms, they may recommend a psychological or psychiatric assessment.

Diagnostic steps may include:

  • A physical exam. This exam aims to rule out physical conditions that could be causing the symptoms.
  • Psychological assessments. These assessments may take the form of questionnaires or talk sessions with a mental health professional to assess the patient’s mood, mental state, and mental health history. Family members or caregivers may also be asked to participate in these assessments.

After medical causes are ruled out, medical professionals can consider whether the patient meets the diagnostic criteria for PDD. These criteria include:

  • The person has experienced a depressed mood for most of the day on most days for at least two years.
  • At least two symptoms of depression are also present. These symptoms include appetite problems, sleep problems, low energy, low self-esteem, concentration problems, or hopelessness.
  • The symptoms have not gone away for more than two months at a time.
  • The person has not had a manic episode and doesn’t meet the criteria for cyclothymic disorder.
  • The symptoms aren’t explained by persistent schizoaffective disorder, schizophrenia, delusional disorder, or other specified or unspecified schizophrenia spectrum or other psychotic disorder.
  • The symptoms cause significant distress or impairment of daily functioning.
  • The symptoms aren’t caused by substance use or a medical condition.


How Is Persistent Depressive Disorder Treated?

PDD has no known reliable cure, but a combination of medications and psychotherapy is often effective at reducing symptoms in many patients.


Several different medications may be used to treat and manage the symptoms of major depression. Individual medication plans depend on the patient’s age, responsiveness to treatments, and the severity of their symptoms. The most commonly prescribed medications include:

  • Selective serotonin reuptake inhibitors (SSRIs). These drugs work by increasing serotonin, a neurotransmitter chemical in the brain, and higher serotonin levels seem to help elevate mood in many people. Common SSRIs include citalopram, escitalopram, fluoxetine, paroxetine, sertraline, and vilazodone.
  • Serotonin-norepinephrine reuptake inhibitors (SNRIs). These drugs work similarly to SSRIs in that they increase serotonin levels, but they also increase the level of norepinephrine, another neurotransmitter.


A combination of medication and psychotherapy is often the most effective approach to controlling the effects of depression. The most common therapeutic approach is cognitive-behavioral therapy (CBT). This process focuses on helping the patient identify a pattern of harmful thoughts and construct strategies and solutions for dealing with them that don’t interfere with functionality.

How Does Persistent Depressive Disorder Progress?

While the symptoms of PDD are relatively mild compared to those of major depression, PDD can lead to severe complications if left untreated. Potential long-term consequences of PDD include:

  • Relationship problems
  • Problems at work or school
  • Chronic medical issues
  • Risk of developing major depression
  • Risk of developing other mental health-related issues such as anxiety disorders or personality disorders
  • Substance abuse
  • Suicidal thoughts, suicide attempts, or suicide

How Is Persistent Depressive Disorder Prevented?

There is no way to prevent PDD, but prompt diagnosis and an effective treatment plan can help to manage symptoms. It’s vital for those diagnosed with PDD to seek treatment from mental health providers and stick to any prescribed medication plan. Stopping an antidepressant abruptly can be especially dangerous, as it can cause withdrawal symptoms and a return to a depressive state.

Persistent Depressive Disorder Caregiver Tips

In addition to seeking support from therapy or a support group, caregivers for someone with PDD disorder should consider some of the following self-care tips:

  • Learn as much as possible about the condition.
  • Make time for yourself away from the disorder.
  • Take care of your own physical and mental health. Unfortunately, it is not uncommon for caregivers to experience depression or let their own healthy lifestyle suffer because of stress.

Many people with persistent depressive disorder also suffer from other brain and mental health-related issues, a condition called co-morbidity. Here are a few of the conditions commonly associated with PDD:

Persistent Depressive Disorder Brain Science

Scientists are interested in fully understanding the brain chemistry involved in depression so more effective medications can be developed, particularly for those who don’t respond well to existing drugs. Areas of current research include:

  • The Food and Drug Administration has recently approved the anesthetic ketamine to treat major depression. Scientists developed a form of the drug administered via a nasal spray, and the treatment shows promise for treating medication-resistant depression.
  • Researchers use imaging technologies to look at a part of the brain called the hippocampus, which is smaller than usual in some people with depression. It is possible, scientists think, that the hippocampus in these people does not produce enough new nerve cells in the brain, leading to a depressed mood.

Persistent Depressive Disorder Research

Title: Transdiagnostic Psychotherapy for Veterans With Mood and Anxiety Disorders (TBT-RCT)

Stage: Completed

Principal investigator: Daniel F. Gros, PhD, MA, BS

Ralph H. Johnson VA Medical Center

Charleston, SC

Cognitive-behavioral therapy (CBT) is a brief, efficient, and effective psychotherapy for individuals with depressive and anxiety disorders. However, CBT is largely underutilized within Veteran Affairs Medical Centers (VAMCs) due to the cost and burden of training necessary to deliver the large number of CBT protocols. Transdiagnostic CBT, in contrast, is specifically designed to address numerous distinct disorders within a single protocol. This transdiagnostic approach has the potential to improve the accessibility of CBT within VAMCs dramatically and therefore improve clinical outcomes for Veterans. The proposed research seeks to evaluate the efficacy of a transdiagnostic CBT by assessing clinical outcomes and quality of life in VAMC patients with depressive and anxiety disorders throughout the course of treatment and in comparison to an existing evidence-based psychotherapy, behavioral activation treatment.


Title: Unobtrusive Monitoring of Affective Symptoms and Cognition Using Keyboard Dynamics (UnMASCK) (UnMASCK)

Stage: Recruiting

Principal investigator: Olusola Ajilore, MD, PhD

University of Illinois at Chicago

Chicago, IL

Mood disorders are associated with significant financial and health costs for the United States, partially due to cognitive problems in these patients that can worsen disease course and impair treatment response. This study proposes using smartphone-based technology to monitor cognitive issues in patients with mood disorders by linking brain network changes with predicted worsening mood symptoms. The proposed study will provide evidence for using smartphone-based passive sensing as a cost-effective way to predict illness course and treatment response.


Title: Personalized Indications for CBT and Antidepressants in Treating Depression (CANBIND6)

Principal investigator: Rudolf Uher, MD, PhD

Nova Scotia Health Authority

Halifax, Nova Scotia

Depression currently affects close to 2 million Canadians and is the leading cause of disability worldwide. Pharmacological treatments (antidepressant medication) and psychological treatments such as cognitive-behavioral therapy are available for depression, but most of those who receive treatment have an unsatisfactory response. On average, the combination of pharmacological and psychological treatment achieves better results than either treatment alone. However, the apparently superior combination treatment results may be because different individuals preferentially respond to pharmacological or psychological treatment. The investigators have discovered several clinical factors and biomarkers that predict poor response to commonly used antidepressant medication: history of childhood maltreatment, loss of interest and reduced activity, a biomarker of systemic inflammation, and a genetic marker of sensitivity to the environment. Indirect evidence suggests that the same factors may indicate the need for psychological treatment, but their usefulness as differential predictors of psychological and pharmacological treatment outcomes remains to be established.

The investigators will test the hypothesis that a pre-determined set of clinical variables (history of childhood maltreatment, loss of interest, and reduced activity) and biomarkers (serum C-reactive protein, a marker of systemic inflammation, and short alleles of the serotonin transporter gene promoter polymorphism) differentially predicts response to antidepressants and cognitive-behavioral psychotherapy with clinically significant accuracy.

If this hypothesis is supported, the resulting predictor will allow personalized treatment selection for depression, leading to improved outcomes and healthcare efficiency. Additional objectives include replicating additional predictors and integrative analyses to refine the treatment choice algorithms.

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