sample was preceded by four smaller Danish samples,17, 18, 19, 20, 21, 22, 23, 24 all aiming to investigate the potential interplay between genes and the environment. Collectively, these forerunners informed on the best possible study design to use in the iPSYCH2012 sample (Supplementary Text 1). The following three paragraphs describe the resources and methods used to identify individuals included in the iPSYCH2012 sample.
