The Data Release S900 of the Human Connectome Project (HCP) (downloaded from https://db.humanconnectome.org) consisted of single visits of 897 young adults age 21 to 35 years. All participants underwent an informed consent process. The Washington University Institutional Review Board approved subject recruitment procedures, informed consent forms, and data collection and dissemination. Our analysis excluded one subject whose DSM-IV (American Psychiatric Association 2000) scores were incomplete, one due to missing twin zygosity information (required to define exchangeability blocks for permutation tests), and 209 individuals who met DSM-IV alcohol abuse, alcohol dependence, or marijuana dependence criteria. The remaining 686 young adults comprised data from 264 male and 422 female participants.
