Introduction to the Special Issue: Novel Insights into the Externalizing Psychopathology Spectrum in Childhood and Adolescence from Intensive Longitudinal Data

Externalizing psychopathology is highly prevalent in children and adolescents. Yet,current understanding of the externalizing psychopathology spectrum is predominantly foundedon cross-sectional and conventional longitudinal designs. Compared to these designs, intensivelongitudinal data have greater ecological validity and provide insight into within-personfluctuations and short-term developmental dynamics. In this Special Issue, we bring together aselection of 10 innovative and original empirical articles to demonstrate the benefits of intensivelongitudinal data for understanding the development of the externalizing psychopathologyspectrum during childhood and adolescence, as well as one thoughtful commentary from leadersin the externalizing psychopathology field. In this Introduction to the Special Issue, we describethe articles included in this Special Issue in relation to study designs, timescales, samples, andstatistical modeling techniques. We conclude by considering the implications of intensivelongitudinal data for informing and enhancing our understanding of externalizingpsychopathology with child and adolescent samples, as well as critical future research directions.