that originated in the Family History Research Diagnostic Criteria assessment (Andreasen et al., 1977), and whether they ever felt that their biological parent was an “excessive drinker.” Endorsement of both problem and excessive drinking items was required to code a parent positive by twin report. Consistent with earlier analyses (Waldron et al., 2012, 2013), a parent was coded positive based on self-report or any family history rating.
