Persistent Depressive Disorder (Dysthymia)

Persistent Depressive Disorder (Dysthymia)

Persistent Depressive Disorder (Dysthymia)

Primer

Persistent Depressive Disorder (PDD) is a mood disorder characterized by a depressed mood that occurs for most of the day, for more days than not, for at least two years (one year for children and adolescents). PDD is a consolidation of DSM-IV diagnosis of chronic major depressive disorder and dysthymic disorder.

Epidemiology

The 12-month prevalence in the United States is estimated to be 0.5% for persistent depressive disorder.^[1]

Prognosis

PDD often has an early and insidious onset in childhood, adolescence, or early adulthood.
The disorder, by definition, has a chronic course, and are less likely to resolve, compared to a major depressive disorder episode.^[2]
The presence of high neuroticism, more severe symptoms, worse global functioning, and comorbid anxiety disorders or conduct disorder leads to worse long-term outcomes.

Comorbidity

Early onset is associated with a much higher likelihood of personality disorders (Cluster B and C) and substance use disorders.^[3]
Compared to individuals with major depressive disorder, individuals are also at greater risk for for anxiety disorders, regardless of age of onset.

Risk Factors

Early parental loss or separations is a risk factor for PDD.^[4]
Those with PDD have a higher proportion of first-degree relatives with PDD compared those with other depressive disorders, including major depressive disorder.^[5]

DSM-5 Diagnostic Criteria

Criterion A

Depressed mood for most of the day, for more days than not, as indicated by either subjective account or observation by others, for at least 2 years.

Note: In children and adolescents, mood can be irritable and duration must be at least 1 year.

Criterion B

Presence, while depressed, of at least 2 of the following:

Hopelessness
Energy low or fatigue
Self-esteem is low
Sleep decreased (insomnia) or increased (hypersomnia)
Appetite poor, or overeating
Difficulty making decisions or poor concentration

Mnemonic

The mnemonic HE'S 2 SAD can be used to remember the criteria for persistent depressive disorder (dysthymia in DSM-IV).

H - Hopelessness
E - Energy low
S - Self-esteem
2 - 2 years of symptoms
S - Sleep decreased
A - Appetite poor
D - Difficulty making decisions

The rule of 2's is another way to remember the criteria:

2 years of depressed mood (1 year in children and adolescents)
2 of listed criteria
Any symptom-free period always under 2 months

Criterion C

During the 2 year period (1 year for children or adolescents) of the disturbance, the individual has never been without the symptoms in Criteria A and B for more than 2 months at a time.

Criterion D

Criteria for a major depressive disorder may be continuously present for 2 years.

Criterion E

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

Criterion F

The symptoms in Criterion A are not better explained by schizoaffective disorder, schizophrenia, schizophreniform disorder, delusional disorder, or other specified or unspecified schizophrenia spectrum and other psychotic disorder.

Criterion G

The symptoms are not attributable to the physiological effects of a substance (e.g. - a drug of abuse, a medication) or another medical condition (e.g. - hypothyroidism).

Criterion H

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

Major depression or Persistent Depressive Disorder?

Because the criteria for a major depressive episode include 4 symptoms that are absent from the symptom list for persistent depressive disorder (dysthymia), a very limited number of individuals will have depressive symptoms that have persisted longer than 2 years but will not meet criteria for persistent depressive disorder.
If full criteria for a major depressive episode have been met at some point during the current episode of illness, they should be given a diagnosis of major depressive disorder.
Otherwise, a diagnosis of other specified depressive disorder or unspecified depressive disorder is warranted.^[6]

Specifiers

Onset Specifier

Specify if:

Early onset: If onset is before age 21 years.
Late onset: If onset is at age 21 years or older.

Episode Specifier (for most recent 2 years of persistent depressive disorder)

Specify if (for most recent 2 years of persistent depressive disorder):

With pure dysthymic syndrome: Full criteria for a major depressive episode have not been met in at least the preceding 2 years.
With persistent major depressive episode: Full criteria for a major depressive episode have been met throughout the preceding 2-year period.
With intermittent major depressive episodes, with current episode: Full criteria for a major depressive episode are currently met, but there have been periods of at least 8 weeks in at least the preceding 2 years with symptoms below the threshold for a full major depressive episode.
With intermittent major depressive episodes, without current episode: Full criteria for a major depressive episode are not currently met, but there has been one or more major depressive episodes in at least the preceding 2 years.

Severity Specifier

Mild: Few, if any, symptoms in excess of those required to make the diagnosis are present, the intensity of the symptoms is distressing but manageable, and the symptoms result in minor impairment in social or occupational functioning.
Moderate: The number of symptoms, intensity of symptoms, and/or functional impairment are between those specified for “mild” and “severe.”
Severe: The number of symptoms is substantially in excess of that required to make the diagnosis, the intensity of the symptoms is seriously distressing and unmanageable, and the symptoms markedly interfere with social and occupational functioning.

Remission Specifier

In partial remission: Symptoms of the immediately previous major depressive episode are present, but full criteria are not met, or there is a period lasting less than 2 months without any significant symptoms of a major depressive episode following the end of such an episode.
In full remission: During the past 2 months, no significant signs or symptoms of the disturbance were present.

With anxious distress

Anxious distress is defined as the presence of at least 2 of the following symptoms during the majority of days of a major depressive episode or persistent depressive disorder (dysthymia):
- (1) Feeling keyed up or tense
- (2) Feeling unusually restless
- (3) Difficulty concentrating because of worry
- (4) Fear that something awful may happen
- (5) Feeling that the individual might lose control of himself or herself
Severity:
- Mild: 2 symptoms
- Moderate: 3 symptoms
- Moderate-severe: 4 or 5 symptoms
- Severe: 4 or 5 symptoms and with motor agitation

Note: Anxious distress has been noted as a prominent feature of both bipolar and major depressive disorder in both primary care and specialty mental health settings. High levels of anxiety have been associated with higher suicide risk, longer duration of illness, and greater likelihood of treatment nonresponse. As a result, it is clinically useful to specify accurately the presence and severity levels of anxious distress for treatment planning and monitoring of response to treatment.

With mixed features

A. At least 3 of the following manic/hypomanic symptoms are present nearly every day during the majority of days of a major depressive episode:
- (1) Elevated, expansive mood
- (2) Inflated self-esteem or grandiosity
- (3) More talkative than usual or pressure to keep talking
- (4) Flight of ideas or subjective experience that thoughts are racing.
- (5) Increase in energy or goal-directed activity (either socially, at work or school, or sexually)
- (6) Increased or excessive involvement in activities that have a high potential for painful consequences (e.g. - engaging in unrestrained buying sprees, sexual indiscretions, or foolish business investments)
- (7) Decreased need for sleep (feeling rested despite sleeping less than usual; to be contrasted with insomnia)
B. Mixed symptoms are observable by others and represent a change from the person’s usual behavior
C. For individuals whose symptoms meet full criteria for either mania or hypomania, the diagnosis should be bipolar I or bipolar II disorder.
D. The mixed symptoms are not attributable to the physiological effects of a substance (e.g. - a drug of abuse, a medication, other treatment)

Note: Mixed features associated with a major depressive episode have been found to be a significant risk factor for the development of bipolar I or bipolar II disorder. As a result, it is clinically useful to note the presence of this specifier for treatment planning and monitoring of response to treatment.

With melancholic features

See main article: Melancholic Depression

A. 1 of the following is present during the most severe period of the current episode:
- (1) Loss of pleasure in all, or almost all, activities
- (2) Lack of reactivity to usually pleasurable stimuli (does not feel much better, even temporarily, when something good happens)
B. 3 or more of the following:
- (1) A distinct quality of depressed mood characterized by profound despondency, despair, and/or moroseness or by so-called empty mood,
- (2) Depression that is regularly worse in the morning
- (3) Early-morning awakening (i.e. - at least 2 hours before usual awakening)
- (4) Marked psychomotor agitation or retardation
- (5) Significant anorexia or weight loss
- (6) Excessive or inappropriate guilt

With atypical features

See main article: Atypical Depression

This specifier can be applied when these features predominate during the majority of days of the current or most recent major depressive episode or persistent depressive disorder.

A. Mood reactivity (i.e. - mood brightens in response to actual or potential positive events)
B. 2 or more of the following:
- (1) Significant weight gain or increase in appetite
- (2) Hypersomnia
- (3) Leaden paralysis (i.e. - heavy, leaden feelings in arms or legs)
- (4) A long-standing pattern of interpersonal rejection sensitivity (not limited to episodes of mood disturbance) that results in significant social or occupational impairment
C. Criteria are not met for “with melancholic features” or “with catatonia” during the same episode

With psychotic features

See main article: Psychotic Depression

Delusions and/or hallucinations are present.

With mood-congruent psychotic features:
- The content of all delusions and hallucinations is consistent with the typical depressive themes of personal inadequacy, guilt, disease, death, nihilism, or deserved punishment
With mood-incongruent psychotic features:
- The content of the delusions or hallucinations does not involve typical depressive themes of personal inadequacy, guilt, disease, death, nihilism, or deserved punishment, or the content is a mixture of mood-incongruent and mood-congruent themes

With catatonia

See main article: Catatonia

This specifier can apply to an episode of depression if catatonic features are present during most of the episode.

With peripartum onset

See main article: Peripartum and Postpartum Depression

This specifier can be applied to the current or, if full criteria are not currently met for a major depressive episode, most recent episode of major depression if onset of mood symptoms occurs during pregnancy or in the 4 weeks following delivery.

With seasonal pattern

See main article: Seasonal Affective Disorder (SAD)

This specifier applies to recurrent major depressive disorder.

A. There has been a regular temporal relationship between the onset of major depressive episodes in major depressive disorder and a particular time of the year (e.g. - in the fall or winter). Do not include cases in which there is an obvious effect of seasonally related psychosocial stressors (e.g. - regularly being unemployed every winter).
B. Full remissions (or a change from major depression to mania or hypomania) also occur at a characteristic time of the year (e.g. - depression disappears in the spring)
C. In the last 2 years, 2 major depressive episodes have occurred that demonstrate the temporal seasonal relationships defined above and no nonseasonal major depressive episodes have occurred during that same period.
D. Seasonal major depressive episodes (as described above) substantially outnumber the nonseasonal major depressive episodes that may have occurred over the individual’s lifetime.

Signs and Symptoms

Since these symptoms have been part of the individual's day-to-day experience for many years (especially in the case of early onset), patients may not report depressive episodes unless directly prompted (e.g. - “I've always been this way.”)

Screening and Rating Scales

See main article: Major Depressive Disorder: Screening and Rating Scales

Cornell Dysthymia Rating Scale is also used, but recently developed.

Pathophysiology

A number of brain regions (e.g. - prefrontal cortex, anterior cingulate, amygdala, hippocampus) have been implicated in persistent depressive disorder. Possible polysomnographic abnormalities exist as well.

Differential Diagnosis

Major depressive disorder
- If there is a depressed mood plus 2 or more symptoms meeting criteria for a persistent depressive episode for 2 years or more, then PDD is diagnosed. The diagnosis depends on the 2-year duration, which distinguishes it from episodes of depression that do not last 2 years.
- If the symptoms meet criteria diagnosis of a major depressive episode at any time during this period, then the diagnosis of major depression should also be noted, but it is coded not as a separate diagnosis but rather as a specifier with the diagnosis of persistent depressive disorder.
  - If symptoms currently meet full criteria for a major depressive episode, then the specifier of “with intermittent major depressive episodes, with current episode” would be made.
  - If the major depressive episode has persisted for at least a 2-year duration (i.e. - continuously over the course of 730 days [2 years]!) and is still present, then the specifier “with persistent major depressive episode” is used.
  - If the major depressive episode criteria are not currently met but there has been at least 1 previous episode of major depression in the last 2 years of persistent depressive symptoms, then the specifier of “with intermittent major depressive episodes, without current episode” is used.
  - If the individual has not experienced an episode of major depression in the last 2 years, then the specifier “with pure dysthymic syndrome” is used.
Psychotic disorders
- Depressive symptoms are a common feature in chronic psychotic disorders as well (e.g. - schizoaffective disorder, schizophrenia, delusional disorder). Thus, a separate diagnosis of PDD is not made if the depressive symptoms occur only during the course of the psychotic disorder (including the remission phases).
Depressive or bipolar and related disorder due to another medical condition
- PDD must be distinguished from a depressive or bipolar and related disorder due to another medical condition. If the history, physical examination, or laboratory findings can attribute the depressive symptoms to a direct pathophysiological effects of a specific medical condition (e.g. - Parkinson's disease, Huntington's disease, stroke, multiple sclerosis), then PDD should not be diagnosed.
Substance/medication-induced depressive or bipolar disorder
- A substance/medication-induced depressive or bipolar and related disorder is distinguished from persistent depressive disorder when a substance (e.g. - a drug of abuse, a medication, a toxin) is etiologically related to the mood change.
Personality disorders
- Often, there is evidence of a coexisting personality disorder in PDD. Thus, both diagnoses may be made.

Investigations

As clinically indicated.

Treatment

See main article: Major Depressive Disorder: Treatment

Medication treatment, or a combination of medication plus psychological treatment is better than psychological treatment alone.^[7]
Most treatment principles follow the treatment for major depressive disorder.

Resources

For Patients

For Providers

Articles

Parker, G., & Malhi, G. S. (2018). Persistent Depression: Should Such a DSM-5 Diagnostic Category Persist?. The Canadian Journal of Psychiatry, 0706743718814429.

Research

¹⁾ American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.). Arlington, VA.

²⁾ American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.). Arlington, VA.

³⁾ American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.). Arlington, VA.

⁴⁾ American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.). Arlington, VA.

⁵⁾ American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.). Arlington, VA.

⁶⁾ American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.). Arlington, VA.

⁷⁾ Parikh, S. V., Quilty, L. C., Ravitz, P., Rosenbluth, M., Pavlova, B., Grigoriadis, S., ... & CANMAT Depression Work Group. (2016). Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 clinical guidelines for the management of adults with major depressive disorder: section 2. Psychological treatments. The Canadian Journal of Psychiatry, 61(9), 524-539.

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