Detailed descriptions of the Missouri Adolescent Female Twin Study (MOAFTS) and the Missouri Family Study (MOFAM) methods have been previously reported (Calvert, Bucholz, & Steger-May, 2010; Heath et al., 2002; Waldron, Bucholz, Lynskey, Madden, & Heath, 2013) with summaries pertaining to the current investigation provided below. Procedures for both MOFAM and MOAFTS were approved by the Human Research Protections Office at Washington University. MOFAM was also approved by the Ethics Board of the State Department of Health and Senior Services (which was not required at the time that MOAFTS began).
