The Social and Emotional Development programme (SED) aims to determine the development of emotion understanding and emotion regulation and social cognitions and interactions and their relation with self-regulation and psychopathology. The studies involve several aspects of social and emotional development, but are mainly focused on the variety of aspects that underly the regulation of emotions and social interactions and their relation with self-regulation and psychopathology. This is still a relatively broad perspective, since self-regulation and psychopathology are depending on neuropsychological, cognitive, and social interactive processes. In our studies, self-regulation and regulation of emotion is taken as a major factor in developmental psychopathology. In order to substantialize this claim, the findings with concern to normal development are contrasted with those of a variety of high-risk and clinical groups using cross-sectional and longitudinal study designs. In addition, to address developmental mechanisms interventions and experiments are performed in the context of longitudinal cohort studies while accounting simultaneously for personal and environmental influences.