Persistent Depressive Disorder or Dysthymia
Dysthymia or persistent depressive disorder is a “recurrent depressive disorder without clearly defined episodes.” Its onset tends to be insidious and can occur in adolescence or adulthood. Often, this disorder remains undiagnosed and unrecognized for a long time.
The symptoms center on a low mood, pessimism, and hopelessness. Those who suffer from it experience significant functional impairment and are at risk of dying by suicide.
People who are most at risk in this regard are single people, women, those who live in high-income countries, and those whose family members have suffered from depression.
At the same time, dysthymia has high comorbidity with other psychiatric disorders and little clinical stability over time. That’s why there’s a current debate on the usefulness of preserving the diagnosis of dysthymia as a single nosological entity or considering it as an evolutionary stage of depression and/or bipolar disorder.
Persistent depressive disorder or dysthymia: What is it?
Dysthymia is a chronic affective (mood) disorder that’s associated with inadequate coping strategies in the face of stressful situations.
In addition, this disorder involves sensitivity to stress, increased risk of hospital admission, low productivity at work, comorbidity with other psychiatric disorders, and suffering from other diseases.
Living with the burden of persistent depressive disorder or dysthymia leaves those affected by it dejected and hopeless for much of their lives. And this prolonged and recurrent depressive disorder has been studied very little.
The concept of dysthymia over time
The term “dysthymia” originated in ancient Greece and means “bad mood.” In the Hippocratic school, it was considered part of the broader concept of melancholy, which derived from the intoxication of “black bile”, one of the four “primary humors” described by Hippocrates.
Later, the concept of “dysthymia” was reintroduced in Germany in the early 19th century to describe depressions that have a chronic course.
In 1863, Karl Kudwig Kahlbaum used the term “dysthymia” to refer to forms of melancholy that had only one phase and in an attenuated manner, as during that time, all mood disorders were included within what was considered manic-depressive psychosis. In fact, this denomination continued to be in use until not too long ago.
In 1921, Emil Kraepelin described the relationship between manic-depressive disorder and depressive temperament. He suggested that the second was only an attenuated form, but that it belonged to the same pathological constellation. Although Kraepelin didn’t use the term “dysthymia”, he considered a depressive disposition as one of the constitutive bases of affective episodes.
In 1923, Kurt Schneider described dysthymic or depressive psychopathy in regard to a combination of neonatal and hereditary factors, as well as early environmental variables, without specifically considering it as a mood disorder. Therefore, he described a type of depression whose existence implied only “suffering.”
For Schneider, individuals with this condition were characterized by being unable to have fun, being sad, being prone to guilt, having a lack of confidence and low self-esteem, feeling sad, and being slow, non-assertive, shy, and sensitive.
Somehow, Schneider considered this type of depressive psychopathy to be a personality disorder.
From the 1950s
It wasn’t until the 1950s that, thanks to the influence of Schneider, the Diagnostic and Statistical Manual of Mental Disorders II (DSM-II), and the ninth version of the International Classification of Diseases (ICD-9) suggested that chronic depression is equivalent to character neurosis.
Therefore, the term “neurotic depression” appears in the DSM-II and “depressive neurosis” in the ICD-9, being considered in both manuals as non-chronic episodes.
Later, the DSM-III changed the reference from chronic depression to “dysthymic disorder.” Thus, DSM-II’s “neurotic depression” was replaced and included in the chapter on affective disorders.
Later, the DSM-III-R incorporated the classification of late-onset and early-onset dysthymia. Later, in the DSM-IV, the criteria consider it as a chronic unipolar affective disorder, which can start early or late and whose symptoms are milder than those observed in a major depressive episode.
The diagnosis of dysthymia or persistent depressive disorder
The process of diagnosing this disorder isn’t straightforward. For many people, it’s a constant battle against mild depression, a sad mood, and a lack of enthusiasm that have become a way of life.
Once known as neurotic depression, in 1980 the diagnosis of dysthymia was introduced in the third edition of the DSM. So, from that moment on, the depressive symptoms of dysthymia were characterized as less severe but more lasting than those of major depressive disorder.
Therefore, dysthymia was associated with alterations in appetite, sleep, energy, self-esteem, concentration, and feelings of hopelessness.
Later in the 2000s, the diagnosis of chronic depressive disorder was introduced in the DSM-IV-TR, in which the symptoms of loss of interest in daily activities, depressed mood, and deterioration of social, occupational, or educational functions persist for more than two years.
The DSM-5 currently merges the diagnoses of chronic depressive disorder and dysthymia in persistent depressive disorder, which is often identified as dysthymia.
This is diagnosed in adults when people have suffered from depressive symptoms for more than 2 months over the course of 2 years and haven’t experienced an episode of major depression or mania.
In children and adolescents, the criteria cover a period of 1 year. However, two of the key features of dysthymia are:
- The episodes aren’t well-defined.
- The duration’s long and can occur both below and above the cut-off points stipulated for 1 or 2 years.
There are those who suffer from dysthymia and can only seek help after experiencing depressive symptoms for decades rather than just after 2 years.
Dysthymia often coexists with other psychiatric illnesses. Many people with dysthymia also develop major depressive disorder (MDD), a condition known as double depression.
This disorder is characterized by the following symptoms, which occur most of the day and/or every day for 2 weeks:
- Insomnia or hypersomnia
- Difficulty focusing
- A depressed mood
- Loss of interest or pleasure
- Weight gain or loss
- Psychomotor agitation or retardation
- Suicidal ideation
- Feelings of worthlessness
While the most common symptoms of dysthymia are usually low self-esteem and pessimism, in major depressive disorder, they’re neurovegetative signs related to sleep or appetite disturbances.
However, in both dysthymia and MDD, those affected by the illness suffer from feelings of hopelessness and can’t find relief from their despair. Also, most people with dysthymia develop at least one episode of MDD in their lifetime.
Subtyping of dysthymia
Also, anxiety disorders are often present in people with dysthymia. So much so that some researchers proposed a division of dysthymia into two different subtypes:
- Non-anxious or anergic dysthymia (formerly known as typical)
- Anxious dysthymia (formerly known as atypical)
Anxious dysthymia is hypothesized to have an association with low serotonin, which regulates mood, calm, and composure when faced with stressful events. When people with anxious dysthymia experience stress, their symptoms of insecurity, low self-esteem, and restlessness are exacerbated or worsened.
Non-anxious or anergic dysthymia is hypothesized to be associated with low dopamine. This neurotransmitter participates in motivation, thinking, and motor activities. When people with anergic dysthymia perceive that they’ve made a mistake, they’re likely to demonstrate more intense manifestations of slow reactivity, low drive, low energy, and psychomotor inertia.
Combined with the prolonged duration of their depressive illness, this subtyping of symptoms suggests that these traits may have evolved as a way in which people cope with stress and the failures they believe they’re facing.
At the same time, personality disorders, somatoform disorders, and substance abuse disorders also often coexist with dysthymia. Other diseases that have been associated with this are levels of dependence on alcohol and substance use or headaches or muscle pain.
How are people with dysthymia usually perceived?
Health professionals may perceive patients as people who display sarcastic, nihilistic, stingy, demanding, and complaining behaviors, rather than people who experience prolonged and deep sadness.
Having endured their illness for long periods of time, people with dysthymia may project pessimism, melancholy, and a lack of self-confidence.
Instead of seeking help for a mood disturbance, they may describe a feeling of general malaise, lethargy, and chronic fatigue. That’s why the diagnosis can be difficult.
The chronic nature of dysthymia can cause further deterioration than acute depression.
Those with dysthymia are less likely to work full-time and frequently receive supplemental income. What’s more, their disorder’s more likely to interfere with certain social activities as a result of emotional and physical problems.
For those with co-occurring personality disorders, dysthymia imposes a significant additional impairment on their psychosocial functioning.
While the cause of the disorder may not be clear, physiologic abnormalities have been associated with dysthymia. For example, polysomnography or sleep studies have indicated irregularities such as shorter periods of dreamless sleep.
Furthermore, it appears that people affected by dysthymia take a shorter period of time to enter REM sleep and have a higher frequency of rapid eye movements during REM sleep.
Interleukin-1, a group of 11 cytokines that plays a central role in regulating immune and inflammatory responses, may be elevated. Also, serotonin, a neurotransmitter, may have a lower maximum absorption rate in people with dysthymia.
At the same time, in women with dysthymia, the activity of platelet monoamine oxidase, which is necessary for the functioning of neurotransmitters, may be lower.
Furthermore, as seen in major depressive disorder, increased neuronal activity or functional connectivity within the brain’s default mode network (DMN) may be important in the pathophysiology of dysthymia.
Psychosocially, severe childhood events and stressful life events, such as the loss of a partner or a serious illness, may predispose people to dysthymia.
Also, people whose family members have suffered from major depression, bipolar disorder, dysthymia, and personality disorders are particularly susceptible. Women and single people are often at higher risk, as are people living in middle- and high-income countries.
Cornell dysthymia rating scale
The Cornell Dysthymia Rating Scale, first developed by Mason and colleagues in 1993, is now an effective screening tool for persistent depressive disorder. It’s a simple and straightforward questionnaire that all members of healthcare teams can easily implement.
It’s a 20-item scale specifically developed to assess the frequency and severity of dysthymia symptoms during the previous week. Items are scored on a basis of 0 to 4. They have a total score range of 0 to 80, with higher scores indicating greater severity of symptoms.
The scale can be self-rated or clinically rated and refers to recent and current symptoms rather than normal premorbid periods, making it particularly suitable for assessing chronic and recurrent symptoms of dysthymia.
The strength of the scale’s severity range scores, concurrent validity, and content validity indicate that it’s a valuable instrument. It’s also a useful tool to monitor how you respond to treatment.
Studies have consistently reported the superiority of treating dysthymia with a combined approach of antidepressant medication and psychotherapy.
In general, cognitive-behavioral therapies are used and, as an antidepressant, nefazodone (serozone). Other antidepressants that can be considered are selective serotonin reuptake inhibitors (SSRIs).
Professionals may also consider monoamine oxidase inhibitors (MAOIs) such as moclobemide/manerix, or tricyclic antidepressants such as imipramine/tofranil.
A complex condition
Dysthymia is a condition that can be difficult for professionals to diagnose. If you think you may have dysthymia, seeing a mental health professional (both a psychologist and a psychiatrist) as soon as possible could help improve your mood.It might interest you...