Current research is centered mainly on the age group between 6–12 years. The assessment in preschool age and in adolescence seems to present additional difficulties. DSM III criteria for major depression in childhood are slowly recognized internationally. Newly developed rating scales help to standardize clinical and research assessment methods. Biologic markers show deviations similar to those in depressed adults. Epidemiologic data are still not sufficient. The bridging to the development and disturbances of affect attunement between caretaker and child, to family interactions and to environmental stresses has not yet been established in a satisfactory manner.