April 2019 By PsychDB.com

Persistent Depressive Disorder (Dysthymia)

Persistent Depressive Disorder (PDD) is a mental disorder characterized by regular low mood, but where the symptoms are not as severe as a major depressive episode. Persistent depressive disorder is a new diagnosis in the DSM-5, which represents a consolidation of the DSM-IV-defined chronic major depressive disorder and dysthymic disorder.

Epidemiology

Childhood risk factors include parental loss or separation.

Comorbidity
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.

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
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 dysthymia?

Because the criteria for a major depressive episode include four 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.

Mnemonic

The mnemonic HE'S 2 SAD can be used to remember the criteria for persistent depressive disorder (dysthymia in DSM-IV).[1]

  • H Hopelessness
  • E Energy low
  • S Self-esteem
  • 2 2 years worth 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 (below)
  • Any symptom-free period always under 2 months

Specifiers

  • With anxious distress
  • With mixed features
  • With melancholic features
  • With atypical features
  • With mood-congruent psychotic features
  • With mood-incongruent psychotic features
  • With peripartum onset
  • In partial remission
  • In full remission
  • Early onset: If onset is before age 21 years.
  • Late onset: If onset is at age 21 years or older.
  • 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
  • Moderate
  • Severe

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.