The Prospective Study was launched in 2004 as a part of COGA, with the goal of examining how genetic risk unfolds across development and in conjunction with the environment. Offspring between ages 12 and 22 with at least one parent in either the clinically ascertained group or the unascertained comparison group who had completed an interview in the original COGA study were recruited to participate and followed longitudinally (Bucholz et al., 2017). In this study, we included 937 (776 from the clinically ascertained group) European ancestry participants (based on ancestral principal components derived from genetic data) between the ages of 21 and 25 with available genetic data. We limited our sample to only participants of European ancestry so that our analytic sample was ancestrally matched to the discovery sample used to calculate genome-wide polygenic scores. Participants were followed-up biennially, with each participant assessed up to three times between ages 21 and 25, resulting in a total of 1,691 assessments. In total, 34.8%, 50.0%, and 15.3% of participants completed one, two, and three assessments.
