The ROOTS study is a longitudinal study of teenagers established in 2006 to evaluate the relative contributions of defined genetic, physiological, psychological and social variables, occurring at different stages of child development, to the overall risk for psychopathology during adolescence. In particular, ROOTS aims to explore genetically influenced intermediate biology (e.g. endophenotypes and biomarkers) that precede, correlate with/or predict dimensional risk markers (e.g. subthreshold symptoms) for future mental illnesses.