All modeling was conducted in Stata, version 14.0 (Stata Corp, 2015). Cox proportional hazards multivariate regression was used, including time-varying covariates to account for the temporal ordering of events preceding each of the transition outcomes – first drink, first drink to first AUD problem, first drink to first AUD diagnosis, and first AUD problem to first AUD diagnosis. Variables for which age of onset was obtained were coded as time-varying; that is, they were counted as “risk factors” only if they occurred either prior to or at the same age as the outcome. For example, if age at onset of cannabis use preceded/occurred at the same time as the age of onset of first drink, it was coded as an event, but if it occurred after the age of first drink, it would not contribute toward the risk of transitioning to using alcohol. Variables modeled in this way included ever-use of cannabis, internalizing conditions, externalizing disorders, and assaultive and nonassaultive traumas. Maternal and paternal AUD statuses were lifetime measures and were time-invariant; parental separation and perceived peer substance use were
