Substance use does not exist in a vacuum; it is entwined with mental and physical health and with our social systems in myriad complex ways, as is neurodevelopment. Thus, even as the ABCD study was being conceived, the CRAN Institute Directors realized that it would have to address a wide range of questions about genetic influences and environmental exposures on neurodevelopment during the second decade of life. Other Institutes, Centers, and Offices across the NIH similarly recognized the value of the proposed cohort for addressing pressing questions in their own priority areas. Answers to these questions could inform policies and practices to improve public health in a variety of ways (see Table 1 below).Table 1Potential Implications of ABCD Study for Policy and Practice.Table 1Questions the ABCD Study Could Answer:Implications for Policy/Practice:Are there differences in marijuana use/consequences between youth from states where it is illegal and those where it is legal for adult recreational use or for medical use?Marijuana laws/regulationsHow does use of e-cigarettes influence youth uptake and use of other tobacco products as well as alcohol and other drugs?E-cigarette laws/regulationsAre
