Persistent Depressive Disorder (Dysthymia) – Signs, Treatment and Differentiating from MDD

Persistent Depressive Disorder: Understanding the Long-Term Battle with Low Mood

Persistent Depressive Disorder (PDD), also known as dysthymia, is a chronic form of depression that lasts for years, often making it difficult for individuals to remember a time when they felt well. Characterized by a persistent low mood, PDD can profoundly affect a person’s daily life, relationships, and overall functioning. In this article, we delve into the symptoms of Persistent Depressive Disorder, explore the diagnostic criteria as per the DSM-5, discuss treatment options and explore the nuance between PDD and MDD.

Signs and Symptoms of Persistent Depressive Disorder

• Chronic Low Mood: A predominant feature of PDD is a continuous, long-term (two years or more) low mood or sadness. Individuals may describe this as feeling ‘down’ or ‘blue’ most of the day, more days than not.

• Lack of Interest in Daily Activities: There is often a loss of interest or pleasure in daily activities, hobbies, or pastimes that used to be enjoyable.

• Low Energy and Fatigue: Persistent feelings of tiredness or low energy are common, making daily tasks feel particularly draining.

• Changes in Appetite and Sleep Patterns: Some individuals experience significant changes in appetite or sleep patterns, either sleeping too much or too little, or overeating or having a poor appetite.

• Low Self-Esteem: Feelings of inadequacy, low self-worth, or excessive guilt may persist.

• Difficulty Concentrating and Making Decisions: There can be noticeable trouble in focusing, thinking clearly, or making decisions.

• Feelings of Hopelessness: PDD often brings a sense of pessimism and hopelessness about the future, with a bleak outlook and inability to see things improving.

DSM-5 Criteria for Persistent Depressive Disorder

The DSM-5 criteria for diagnosing PDD are as follows:

1. Depressed mood for most of the day, more days than not, as indicated by either subjective report or observation by others, for at least two years.

2. Presence, while depressed, of two (or more) of the following:

   • Poor appetite or overeating.
   • Insomnia or hypersomnia.
   • Low energy or fatigue.
   • Low self-esteem.
   • Poor concentration or difficulty making decisions.
   • Feelings of hopelessness.

3. During the two-year period, the individual has never been without the symptoms for more than two months at a time.

4. Criteria for a major depressive disorder may be continuously present for two years.

5. There has never been a manic episode or hypomanic episode, and criteria have never been met for cyclothymic disorder.

6. The symptoms are not attributable to the physiological effects of a substance or another medical condition.

7. The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.

Differentiating Persistent Depressive Disorder (PDD) from Major Depressive Disorder (MDD)

Dysthymia, now known as Persistent Depressive Disorder (PDD), and Major Depressive Disorder (MDD) are both mood disorders characterized by depression, but they differ primarily in their duration and severity. PDD is marked by a chronic state of depression that is present most of the time for at least two years, with sufferers often experiencing a consistent low mood, but likely at a less severe intensity than MDD. MDD is marked by acute episodes of depression that typically are more severe but generally only last weeks to months. To better explain the concept of severity we can look at the DSM-5 which shows that, among other criteria, PDD only requires 2 depressive symptoms to be diagnosed while MDD requires 5 depressive symptoms to be diagnosed. The DSM-5 differentiates duration by specifying that PDD requires 2 years of symptoms, while MDD only requires 2 weeks of symptoms to diagnose.

The DSM-5 now more clearly characterizes the difference between PDD and MDD with ‘specifiers’:

• PDD with intermittent Major Depressive episodes: This specifier describes someone with PDD who at times experiences an acute worsening of their depression, enough that they would meet the 5 criteria necessary to diagnose MDD. In this case their primary diagnosis remains PDD, the specifier is simply added in addition to describe the current situation.
• PDD with persistent Major Depressive episodes: This specifier describes someone whose depressive symptoms are severe enough that they have met the 5 criteria for MDD for two years now. In this case, their diagnosis would change from MDD to PDD with persistent major depressive episodes.
• PDD with pure dysthymic syndrome: This specifier describes someone who, in the last 2 years, has never met criteria for a major depressive episode. In other words, they purely experience dysthymia or PDD without any flares of major depression. 

Double Depression

“Double depression” describes someone with long standing, chronic depression (PDD) who is now experiencing an acute worsening of depressive symptoms. Though it is a somewhat antiquated term that is not commonly taught or discussed in psychiatric nomenclature, it remains a useful concept for understanding the overlay of acute depressive episodes on chronic depression. The long-term nature of PDD can lead to it being perceived as a part of the individual’s personality or life experience. In modern times, it is more accurately thought of as a continuous, long-term mood disorder. However, exploring the concept of PDD as a set of personality traits could be a valuable therapeutic approach, offering insights into the chronic nature of the condition, its origins and its impact on an individual’s overall personality and behavior. Psychodynamic therapy is a particularly useful tool for exploring personality traits and their overlap with depressive symptoms.

Epidemiology of Persistent Depressive Disorder

• Prevalence: The 12-month prevalence of PDD in the United States is estimated to be about 0.5%, meaning in a 1 year period about 0.5% of the population will meet criteria for PDD. The lifetime prevalence of PDD is estimated to be about 5%, meaning that about 5% of people will experience PDD in their lifetime.
• Age of Onset: The disorder often begins in early adulthood, but can start at any time from childhood to later life.

Treatment Options for Persistent Depressive Disorder

• Psychotherapy:  Psychodynamic psychotherapy and Cognitive-Behavioral Therapy (CBT) are common and effective forms of treatment for PDD. Psychodynamic therapy is a particularly useful tool for PDD, especially in the context of exploring a person’s personality traits and their overlap with depressive symptoms. Psychodynamics can be particularly useful in this disorder, as often patients have tried more common modalities of therapy such as CBT without success. That being said, CBT can certainly be useful, especially in helping to restructure negative thought patterns.
• Medications: Antidepressants, particularly SSRIs and SNRIs, can be helpful in managing the symptoms of PDD.
• Lifestyle Changes: Regular physical activity, a healthy diet, sufficient sleep and healthy relationships can all play a role in managing symptoms.
• Accurate Diagnosis: 

Summing Up Persistent Depressive Disorder 

Persistent Depressive Disorder is a long-term challenge that requires ongoing attention and care. Understanding the nature of this disorder, its symptoms, and available treatment options is crucial for those suffering from it and their loved ones. If you believe you or someone you know might be experiencing symptoms of PDD, seeking professional help is a critical step towards managing the condition and improving quality of life. Remember, support and effective treatments are available, offering hope for those living with PDD.