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 prev