ICD-116A72	DYSTHYMIC DISORDER Dysthymic disorder
ICD-10F34.1	Dysthymia
DSM-5-TRF34.1	Persistent Depressive Disorder

1. Definition and nosology

Dysthymic disorder (ICD-11: 6A72; DSM-5-TR: Persistent Depressive Disorder — F34.1) — chronic depressive symptoms lasting at least 2 years (in adults; 1 year in children/adolescents) that do not meet the severity of a major depressive episode. The patient may describe their state as 'I've always been this way'.

DSM-5-TR — the term “Persistent Depressive Disorder” combines dysthymia and chronic major depressive disorder; ICD-11 codes dysthymic and chronic depressive episode separately.

2. History

• Flemming C.F. (1844) — first psychiatric use of the term “dysthymia”; Kahlbaum (1882) — gave it its modern meaning as a chronic, subthreshold depressive state.
• Akiskal H.S. (1980s) — dysthymic temperament as a substage of the depressive spectrum.
• DSM-III (1980) — official diagnosis “Dysthymic Disorder”.
• DSM-5 (2013) — “Persistent Depressive Disorder” — merger of dysthymia and chronic MDD.
• ICD-11 (2019) — dysthymic disorder retained separately.

3. Epidemiology

• Lifetime prevalence: 1.1–6.4% (dysthymia); 12-month prevalence in the US ~0.5%, plus 1.5% for chronic major depression (DSM-5-TR).
• Sex: 2 times higher in females.
• Onset: early (childhood/adolescence — early-onset; ≥ 21 years — late-onset).
• “Double depression” — major depressive episode on a background of dysthymic disorder — occurs in 76.9% of patients within 5 years (Klein D.N. et al. Am J Psychiatry 2000;157(6):931–939).
• Comorbidity: anxiety, BPD, substance use.

4. Aetiology and pathogenesis

• Shared genetic and neurobiological predisposition with major depressive disorder.
• Childhood trauma and chronic psychosocial stress are key environmental risk factors.
• The frequency of depressive disorder or dysthymia is increased in close relatives.

5. Clinical features

• Persistent low mood — present most of the time (≥ half the time, no symptom-free period > 2 months over 2 years).
• At least 2 of the following: low or increased appetite, insomnia or hypersomnia, low energy, low self-esteem, concentration difficulty, hopelessness.
• The patient has adapted to numerous functional compromises — the explanation “I have always been like this” is typical; they often present to the clinic against a background of a major depressive episode.

6. Diagnosis

6.1 Unified diagnostic criteria

A. Persistent depressive mood ≥ 2 years (children ≥ 1 year), most of the day, most of the time.

B. ≥ 2 symptoms during depressive episodes (above)

C. No symptom-free period longer than 2 months within 2 years (1 year).

D. During this period, criteria for a major depressive episode may be continuously present (DSM-5 — new “double depression” synthesis).

E. Never had a manic or hypomanic episode.

F. Not better explained by schizoaffective or other psychotic disorder.

G. Exclusion of substance or medical condition.

H. Significant distress or functional impairment.

6.2 Differences between sources

• DSM-5-TR: “Persistent Depressive Disorder” — combines dysthymia and chronic MDD; qualifiers — early/late onset, with/without anxious distress, melancholic, atypical, peripartum, seasonal, etc.
• ICD-11: dysthymic disorder (6A72) separate; chronic depressive episode within 6A70/71 qualifier.

6.3 Diagnostic algorithm

1. Clinical interview + long-term history (patient may not recall exact onset).
2. SCID-5; PHQ-9, HAM-D, MADRS.
3. Bipolar screening.
4. Personality assessment – differential with BPD.
5. Medical and laboratory (thyroid, anemia, B12).

6.4 Differential diagnosis

7. Examination and assessment

• PHQ-9, HAM-D, MADRS.
• Cornell Dysthymia Rating Scale — dysthymia-specific.
• Medical and laboratory.

8. Treatment

1. Pharmacotherapy: SSRI (sertraline, fluoxetine) — first-line; the effect may take 6–8 weeks (slower than in major depression).
2. Psychotherapy: CBASP (Cognitive Behavioral Analysis System of Psychotherapy — McCullough J.) — specifically developed for chronic depression; CBT, IPT.
3. Combination — superior to monotherapy in dysthymic disorder (Keller M.B. et al. NEJM 2000 – nefazodone + CBASP RCT).
4. In “double depression” — the management includes acute treatment of a major depressive episode + long-term maintenance therapy.
5. Refractory — medication switch, augmentation (lithium, atypical antipsychotic).

8.1 Treatment methods

1. Cognitive Behavioral Analysis System of Psychotherapy (CBASP — Cognitive Behavioral Analysis System of Psychotherapy) — McCullough (McCullough J.) — Approach specifically developed for chronic depression — situation analysis, interpersonal behavior teaching, use of therapeutic relationship as main tool. Keller M.B. et al. NEJM 2000 RCT.
2. SSRI long-term — Sertraline, fluoxetine, escitalopram; slow response; prolonged maintenance.
3. CBT and IPT — Standard depression therapies; modified for chronic form.

8.2 Differences between sources

• NICE NG222 — recommends long-term cognitive behavioural treatment for chronic depressive symptoms (CBASP is not named in the guideline); CBASP is named by APA 2010.
• APA 2010 — combination superior.
• Keller M.B. et al. NEJM 2000 — nefazodone + CBASP combination significantly superior to monotherapy.

9. Prognosis

• Chronic course; spontaneous remission is rare.
• “Double depression” — develops in 76.9% of dysthymic patients without a prior major episode within 5 years (Klein D.N. et al. Am J Psychiatry 2000).
• Functional level improves with long-term treatment.
• Monitoring — periodic scales, compliance, comorbidity.

10. Myths and misconceptions

Myth 1: “Dysthymia is just a ‘gloomy character’, not a medical disorder”

Evidence: persistent functional impairment, suicidality risk, development of “double depression”; should be evaluated as a medical disorder.

Myth 2: “Dysthymic patient does not respond to antidepressants”

Evidence: The response is slow — 6 to 8 weeks, but SSRIs are effective; combination with CBASP superior.

Myth 3: “Chronic depression only requires psychotherapy; medications are ineffective”

Evidence: Keller NEJM 2000 — nefazodone + CBASP combination superior to monotherapy; pharmacotherapy is a core component.

Myth 4: “The patient's explanation 'I've always been like this' is not a basis for diagnosis — it should be accepted as adaptation”

Evidence: This patient perspective creates a problem of under-detection — long-term functional compromise may be a marker of medical condition.

Myth 5: “Herbal preparations are a safe alternative for dysthymia”

Evidence: St John's Wort demonstrates some efficacy in mild depression, but CYP induction interactions; standard antidepressants superior.

11. Sources

1. WHO. ICD-11. 6A72 Dysthymic disorder. 2024.
2. APA. DSM-5-TR. 2022.
3. NICE NG222. 2022.
4. Keller M.B., McCullough J.P., Klein D.N. et al. A comparison of nefazodone, the cognitive behavioral-analysis system of psychotherapy, and their combination for the treatment of chronic depression. NEJM 2000;342(20):1462–1470.
5. Klein D.N., Shankman S.A., Rose S. Ten-year prospective follow-up study of the naturalistic course of dysthymic disorder and double depression. Am J Psychiatry 2006;163(5):872–880.
6. McCullough J.P. Treatment for Chronic Depression: Cognitive Behavioral Analysis System of Psychotherapy. Guilford Press; 2000.