use unfolds over time, further elucidating the mechanisms underlying the development of substance use behaviour. For instance, Korhonen et al. [20] found that part of the additive genetic and shared environmental factors underlying externalizing behaviour in early adolescence is also involved in smoking behaviour at age 14 and illicit drug use by age 17. Likewise, Silberg et al. [21] demonstrated that early conduct disturbance is related to mid-adolescent substance use through common genetic and shared environmental risk factors.
