While it was clear that a large-scale study of adolescent brain and cognitive development was needed to answer these broad yet interrelated questions, a clearly defined scientific framework was still needed to guide the development of the Funding Opportunity Announcements (FOAs). In May 2014, NIDA, NIAAA, NCI, NICHD, and NIMH convened an expert panel workshop meeting summary at https://addictionresearch.nih.gov/summary-expert-panel-meeting to develop recommendations for the best large-scale research designs and measures to assess the developmental effects of substance exposure. The expert panel discussed key research questions such a study should answer, as well as critical design elements from sampling size and strategy to imaging, cognitive, and other behavioral measures. There was general agreement that the study should be large and longitudinal, recruiting participants prior to substance use initiation (e.g., beginning at ∼ages 10–12) and following the cohort throughout the period of greatest risk (∼ages 19–21). Importantly, the meeting focused on how the ABCD Study could go beyond what other smaller studies had achieved, to serve as a platform for scientific discovery and a foundation for parallel mechanistic studies in animal models.
