Persistent Depressive Disorder

This article details the major aspects of persistent depressive disorder, including its symptoms, causes, long-term impacts, and prevention and treatment strategies.

Key Takeaways:

• Persistent depressive disorder is often overlooked, yet it often has more negative impacts compared to non-chronic forms of depression

• Due to its chronic nature, this disorder can lead to severe impairments in life functioning and overall well-being. It also increases the likelihood of suicidal thoughts and behaviors

• People with persistent depressive disorder respond best to early treatment, especially from a combination of medication and talk therapy, supplemented by social support, healthy lifestyle practices, and strengthening key skills, such as emotional regulation

What is Persistent Depressive Disorder?

Persistent depressive disorder (PDD) is listed in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) under the category of depressive disorders. It is a relatively new disorder and first showed up in theDSM-5, which essentially combined aspects of dysthymia and chronic major depressive disorder (MDD) to create the consolidated diagnosis of PDD.^[1]

PDD is a chronic mental disorder, which makes it distinct from episodic forms of depression, such as in MDD. It is characterized by a persistent negative or low mood for more days than not, for a period of at least two years for adults and one year for children or adolescents. During this time, people may experience periods of better or worse symptoms, but the symptoms never completely resolve. Due to the chronic nature, PDD is also often associated with worse outcomes compared to other non-chronic forms of depression.^[1][2]

Prevalence of PDD

Estimates on the prevalence of PDD aren’t definitive since it’s a relatively new disorder. However, the estimated prevalence of dysthymia and chronic MDD are 0.5 and 1.5%, respectively, which means PDD likely affects around 2% of the population.

In addition, rates of chronic depression are nearly twice as high in women compared to men. PDD is also higher in high-income countries, although overall there isn’t a clear relationship with race, ethnicity, or education level.^[3]

Symptoms of Persistent Depressive Disorder

Persistent depressive disorder symptoms are similar to MDD and other depressive disorders, but the key is that these have been maintained for at least two years in adults or one year for children or adolescents.

The main symptoms of persistent depressive disorder are:^[1][4]

• Sadness, emptiness, or depressed mood

• Lack of interest or pleasure in activities

• Fatigue, lack of energy

• Poor self-esteem

• Being overly self-critical

• Poor focus and trouble thinking

• Easily irritated, annoyed, or angered

• Social withdrawal or isolation

• Changes in appetite

• either low/no appetite or overeating/strong cravings

• Sleep problems

• Either trouble sleeping (insomnia) or sleeping too much (hypersomnia)

• Feeling hopeless

Long-Term Impact of PDD

PDD is associated with a number of long-term impacts. In general, PDD is associated with worse outcomes compared to non-chronic forms of depression, and individuals are less likely to respond well to treatment over time.^[1][3]

PDD increases the likelihood of suicidal thoughts and behaviors, and usually to a greater degree than compared to non-chronic forms of depression. Many individuals with PDD are more likely to develop MDD as well, which when combined leads to intensified depressive symptoms.^[1][2][5]

Many individuals with PDD also experience other mental health problems too, such as anxiety, substance use disorders, and somatic (physical) symptoms, such as fatigue, aches and pains, and digestive issues. They are also more likely to be unemployed, experience social relationship difficulties, and have lower life quality satisfaction.^[1][3][5]

Causes of Persistent Depressive Disorder

Persistent depressive disorder is very likely caused by a combination of factors. Biological, genetic, social, psychological, life history, and environmental factors may all play a role, depending on each individual.

For example, brain abnormalities, differences in serotonin and other neurotransmitter function, and dysregulated sleep patterns are possible biological causes. PDD is also partly heritable, although the exact genes haven’t been identified.^[1][4]

PDD is also likely caused in part by life stress, especially early trauma and maltreatment. One’s temperament and personality may also influence the development of PDD.^[1][2][4]

Risk Factors and Complications

There are many risk factors for PDD. The main ones are:^[1][2][4]

• Negative childhood experiences, such as maltreatment, abuse, or death of a parent

• Prior mental illness

• Having a blood relative with a history of PDD or other depressive disorders

• Personality disorders, especially borderline personality disorder (BPD)

• Psychological factors

• E.g. high neuroticism and anxiety, and low sense of self-worth

• Hypersensitivity and/or poor emotional regulation

• High levels of stress, such as financial or relationship problems

PDD also has high rates of comorbidity with anxiety, depression, and personality disorders, such as BPD. Other common complications include substance misuse, family and relationship troubles, problems at school or work, reduced overall life quality, and suicidal thoughts or behaviors.^[1][4]

Prevention

There are several ways that may help prevent the development of PDD, even for those at higher risk. This includes:^[4]

• Social support through family and friends

• Stress management techniques

• Starting treatment as early as possible

• Employing healthy lifestyle practices as much as possible

Once again, it’s essential to reach out to a healthcare provider as soon as you notice symptoms.

Diagnosing PDD

Diagnosing PDD requires careful, thorough examination. This is particularly important given that PDD is often overlooked, especially since it may initially seem like MDD or other forms of depression. In addition, many individuals with persistent depressive disorder consider their low mood and other common symptoms as “just the way they are” so they may not actually report them during the assessment.^[1][2]

Screening and Detection

Initial screening for PDD can be done in primary care settings, which is helpful because this is where many individuals are used to going for various treatments anyway. The Cornell Dysthymia Rating Scale (CDRS) is an efficient way to initially assess the possible presence of PDD. It consists of 20 items to assess the frequency and severity of dysthymia symptoms.^[5]

After the initial screening, another important part of the diagnostic process is to rule out other medical or psychiatric causes. This often includes:

• Past psychiatric history

• Substance use history

• Medical history

• Current medications

Your healthcare provider will also go over your personal, family, social, and developmental history to get a full overview of all possible involved factors. This will be combined with a physical exam and possibly lab tests to rule out any physical reasons, such as brain lesions, neurological disorders, heavy metal toxicity, or metabolic disorders.^[1]

After this, a psychologist, psychiatrist or other qualified mental health professional will conduct a thorough mental exam and psychiatric evaluation. They may also ask for information from family or other close individuals to gain more information. Symptoms are compared using the diagnostic criteria in the DSM-5, which are:^[1]

• Depressed mood most of the day, for more days than not, for at least two years (or one year for children or adolescents)

• At least two of the following symptoms:

• Poor appetite or overeating

• Hypersomnia or insomnia

• Low energy or fatigue

• Low self-esteem

• Poor concentration or trouble with decision-making

• Feelings of hopelessness

• During the required time period, the individual has not been without symptoms from the above criteria for more than two months

• Criteria for MDD may be continuously present for more than two years

• No past or current manic or hypomanic episode

• Symptoms are not better explained by schizophrenia spectrum disorders or psychotic disorders

• Symptoms are not caused by a substance or medical condition

• Symptoms cause clinically significant impairments in important areas of functioning

Treatment Options for PDD

Treatment options for PDD typically include pharmacological, psychotherapeutic, and combination approaches. Starting treatment as soon as possible is essential to increase the likelihood of positive outcomes.

Pharmacological

Pharmacological treatments refers to the use of medications. Commonly-used medications that have some evidence of benefits for PDD include:^[1][2]

• Selective-serotonin reuptake inhibitors (SSRIs), especially sertraline, fluoxetine, and paroxetine

• Monoamine oxidase inhibitors, such as moclobemide

• Tricyclic antidepressants, such as imipramine

Psychotherapeutic

Psychotherapy, or talk therapy, is another treatment for PDD. One of the most common psychotherapies for PDD is cognitive behavioral analysis system of psychotherapy (CBASP). This therapy combines aspects of cognitive behavioral therapy (CBT) and interpersonal therapy (IPT).

As a result, CBASP helps individuals to:

• Identify and change disruptive/dysfunctional thoughts and behaviors

• Establish better interpersonal relationships and greater social support

• Identify any issues contributing to depressive symptoms

CBASP is also typically more effective than more generalized psychotherapies, given that it’s specifically designed to treat PDD/chronic depression.^[2]

Combination

Combination therapy is the use of medication and psychotherapy together. Overall, combination therapy is the most effective route for the majority of individuals with PDD. It typically leads to greater treatment responses and improved overall functioning.^[1][2][5]

Living with Persistent Depressive Disorder

Persistent depressive disorder can make daily life a significant struggle. There are many things you can do on a regular basis to make living with persistent depressive disorder a bit easier. This includes:^[6]

• Reaching out to family and friends for support

• Learning more about PDD

• And encourage family or others to become more educated too

• Goal-setting (set small, reasonable goals)

• Journaling to express negative emotions

• Eating a healthy diet, regular exercise, adequate sleep, and other healthy lifestyle practices

• Planning your days

• And cut back on unnecessary obligations

• Stress-management techniques, such as yoga, meditation, or mindful breathing

• Avoiding alcohol and recreational drugs

Lastly, it’s important to continue with your treatment plan as best you can, even when you don’t feel like it. Discuss any issues that come up, especially any new problems or anything that may be getting worse.

PDD certainly can be a debilitating disorder. But if you combine these self-help strategies with professional treatment, you greatly increase the likelihood of symptom reduction and improved overall life quality and daily functioning.