Diagnostic Criteria for Depression and Dysthymia

1. Overview & Epidemiology

• Mood = a pervasive, sustained internal feeling tone that colours behaviour and perception of the world; affect = its external expression (Gajdos, UD lecture).
• Major depressive disorder (MDD) / unipolar depression = recurrent or single major depressive episodes with no lifetime manic or hypomanic episode. Persistent depressive disorder (PDD) / dysthymia = chronic, milder depression ≥ 2 years.
• MDD lifetime prevalence ≈ 17% — the highest of any psychiatric disorder (Gajdos / Kaplan & Sadock).
• Yearly incidence of MDD ≈ 1.59% (women 1.89%, men 1.10%). Annual incidence of bipolar illness < 1%.
• Sex: roughly 2× greater prevalence of MDD in women than men — almost universal across countries/cultures. (Bipolar I is equal between sexes.)
• Social factors: MDD is most common in persons without close interpersonal relationships, or who are divorced/separated.
• Comorbidity: alcohol abuse/dependence, panic disorder, OCD, social anxiety disorder.
• Dysthymia: early, insidious onset (childhood/adolescence/early adulthood); chronic course; ~50% develop a superimposed major depressive episode → "double depression."
• ICD-10 codes (Hungary/EU practice): depressive episode F32, recurrent depressive disorder F33, dysthymia F34.1.

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