Dysthymia
Dysthymia, known as persistent depressive disorder in the DSM-5-TR and dysthymic disorder in ICD-11, is a psychiatric condition marked by symptoms that are similar to those of major depressive disorder, but which persist for at least two years in adults and one year among pediatric populations. The term was introduced by Robert Spitzer in the late 1970s as a replacement for the concept of "depressive personality."
With the DSM-5s publication in 2013, the condition assumed its current name, having been called dysthymic disorder in the DSMs previous edition, and remaining so in ICD-11. PDD is defined by a 2-year history of symptoms of major depression not better explained by another health condition, as well as significant distress or functional impairment.
Individuals with PDD, defined in part by its chronicity, may experience symptoms for years before receiving a diagnosis, if one is received at all. Consequently, they might perceive their dysphoria as a character or personality trait rather than a distinct medical condition and never discuss their symptoms with healthcare providers. PDD subsumed prior DSM editions' diagnoses of chronic major depressive disorder and dysthymic disorder. The change arose from a continuing lack of evidence of a clinically meaningful distinction between chronic major depression and dysthymic disorder.
History
Terminology evolution
The terminology of chronic depression has greatly changed as time passed. Historically, symptoms now related to dysthymia were, at times, marked as "neurotic depression" or depressive neurosis." The term dysthymia was officially introduced into the Diagnostic and Statistical Manual of Mental Disorders in 1980 to describe a long-term, less severe but still disabling, form of depression. Later, the American Psychiatric Association, or APA, revised the terminology in the DSM-IV and then in the DSM-5. Renaming the diagnosis to persistent depressive disorder, or PDD, to combine dysthymia and chronic major depressive disorder under a whole, unified category. The DSM-5 rework showcased the significance of the practical impact and prolongation over symptom severity, encouraging wider clinical recognition of chronic symptoms and better consistency in diagnosis and research.Diagnostic milestones
Early recognition
In the late 19th and early 20th centuries, chronic low grade depressive symptoms began to be treated differently from episodic major depression, although there was little consensus on terminology or treatment. The concept of chronic depression stayed almost unrecognized in the first half of the 20th century.Standardization & epidemiological Impact
The official introduction of dysthymia as a distinct disorder in the DSM-III created more systematic study. In the early 2000s, major population based research efforts, such as the National Comorbidity Survey Replication, quantified the gender distribution and social burden of dysthymia in the United States. The NCS-R, led by Harvard and sponsored by NIMH, estimated the lifetime prevalence of dysthymia at 2.5%; women were found to be disproportionately affected. Another critical point, the National Comorbidity Survey Adolescent Supplement , extended this research to youth, showing that chronic depressive symptoms do occur in children and adolescents and are linked to academic struggles, increased peer conflict, and elevated risk for later psychological and behavioral disorders.Impairment and disability
For the first time, robust functional impairment scores were attached to dysthymia using the Sheehan Disability Scale: approximately half of diagnosed adults reported severe disability, with the rest experiencing moderate or mild impacts on their ability to work, socialize, or manage responsibilities. The relation with early life trauma, chronic stress, and comorbid psychiatric disorders has become more documented during this research phase.Developments of research
Expanded understanding
All through the 1990s and 2000s, a growing body of NIMH-sponsored research showed that dysthymia is not simply "milder" depression but a chronic, high burden illness. Longitudinal studies discovered that PDD often begins early, sometimes in adolescence or even childhood, and may last for years to decades without adequate treatment, sometimes dispersed with major depressive episodes. Such findings transferred the clinical focus toward early intervention and long term management.Impact on treatment standards
The increasing emphasis on functional impairment in both clinical trials and public health data led professional organizations to update treatment guidelines, supporting a combination of psychotherapy and, where appropriate, pharmacological interventions. The relapse risk documented in these studies feature the importance of ongoing support and monitoring.Recognition for children
Changing views
In children, chronic depression went heavily unaccounted for by clinicians for much of the 20th century. Assumed to be not common or misdiagnosed as behavioral issues or adjustment disorders, though, by the late 1990s and early 2000s, research from pediatric centers, most notably Boston Children's Hospital, started to reveal the effect of dysthymia in the young. This research highlighted that persistent irritability, academic fall off, somatic complaints, and social withdrawal could be signs of underlying PDD rather than just "growing pains".Diagnostic standards & family assessment
Modern methods, as mentioned by MedlinePlus and leading hospitals, now warrant a full developmental and family psychiatric history as part of a pediatric depression test. Just one year of symptoms is needed for a child or adolescent to meet requirements, while two years is the criteria for adults. Clinicians are now trained to consider family risk, collaborate with schools and families, and even look for the most subtle signs, for comprehensive care planning. Early intervention is now a main concern---both to reduce long-term disability and to intercept the risk of leading to later mental and behavioral health issues.Signs and symptoms
Dysthymia is characterized by a 2-year history of depressed mood, as well as at least two of the following symptoms: poor appetite or overeating, hypersomnia or insomnia, fatigue or low energy, low self-esteem, poor concentration or difficulty making decisions, and hopelessness. Irritability, rather than sadness, may predominate in the pediatric setting.Mild degrees of dysthymia may result in withdrawal from stress-inducing activities and avoidance of opportunities for failure. In more severe cases of dysthymia, the patient may withdraw from daily activities. They will usually find little pleasure in usual activities and pastimes, a symptom of depression known as anhedonia.
Diagnosis of dysthymia can be difficult because of the subtle nature of the symptoms and patients can often hide them in social situations, making it challenging for others to detect symptoms. Additionally, dysthymia is often comorbid with other psychological conditions, adding complexity to dysthymia recognition due to overlapping symptoms. Dysthymia is frequently comorbid with anxiety disorders, substance use disorders, and personality disorders, and suicidal ideation is common.
Causes
There are no known biological causes that apply consistently to all cases of dysthymia, which suggests diverse origin of the disorder. However, there are some indications that there is a genetic predisposition to dysthymia: "The rate of depression in the families of people with dysthymia is as high as fifty percent for the early-onset form of the disorder." More recent studies have indicated that the frequency of dysthymia is likely influenced more heavily by "family environmental and non-shared environmental factors," rather than genetic or neurobiological factors. Part of the reason for the uncertainty with regard to understanding the biological basis of dysthymia is due to the lack of genetic and neurobiological research, genome wide studies, and "grossly underpowered sample sizes." Other factors linked with dysthymia include stress, social isolation, and lack of social support.In a 1998 study using identical and fraternal twins, results indicated that there was not a stronger likelihood of identical twins both having dysthymia than fraternal twins. This provides support for the idea that dysthymia does not have a consistent genetic basis.
Co-occurring conditions
Dysthymia often co-occurs with other mental disorders. A "double depression" is the occurrence of episodes of major depression in addition to dysthymia. Switching between periods of dysthymic moods and periods of hypomanic moods is indicative of cyclothymia, which is a mild variant of bipolar disorder."At least three-quarters of patients with dysthymia also have a chronic physical illness or another psychiatric disorder such as one of the anxiety disorders, cyclothymia, drug addiction, or alcoholism". Common co-occurring conditions include major depression, anxiety disorders, personality disorders, somatoform disorders and substance use disorders. People with dysthymia have a higher-than-average chance of developing major depression. A 10-year follow-up study found that 95% of dysthymia patients had an episode of major depression. When an intense episode of depression occurs on top of dysthymia, the state is called "double depression."
Double depression
Double depression occurs when a person experiences a major depressive episode on top of the already-existing condition of dysthymia. It is difficult to treat, as patients accept these major depressive symptoms as a natural part of their personality or as a part of their life that is outside of their control. The fact that people with dysthymia may accept these worsening symptoms as inevitable can delay treatment. When and if such people seek out treatment, the treatment may not be very effective if only the symptoms of the major depression are addressed, but not the dysthymic symptoms.Patients with double depression tend to report significantly higher levels of hopelessness than is normal. This can be a useful symptom for mental health services providers to focus on when working with patients to treat the condition. Additionally, cognitive therapies can be effective for working with people with double depression in order to help change negative thinking patterns and give individuals a new way of seeing themselves and their environment.
It has been suggested that the best way to prevent double depression is by treating the dysthymia. A combination of antidepressants and cognitive therapies can be helpful in preventing major depressive symptoms from occurring. Additionally, exercise and good sleep hygiene are thought to have an additive effect on treating dysthymic symptoms and preventing them from worsening.