The author describes the part played by developmental psychopathology in the epidemiology of psychiatric disorders. Analysis of three basic perspectives. The problem of age and developmental trends due to the incidence of certain psychiatric diagnoses at a certain age (in a certain developmental period). Continuity and discontinuity of normal and pathological forms of behaviour from childhood to adult age. Time patterns of continuity in diagnostic categories of depression, behavioural disorders and schizophrenia. Perspective of causal mechanisms, where two pathways seemed feasible: research of factors reducing the deviant behaviour and investigation of harmonious marriages.