As shown in Table 3, early alcohol and nicotine use respectively were associated with 1.49 and 1.66 increased odds of SA (when adjusting for demographic covariates alone), although these associations were no longer significant after adjustment for the full set of covariates (Supplemental Table S5), most notably, MDD (OR = 0.33 – 0.59) and having two parents with alcohol use disorders (OR = 1.59 – 2.22). The negative association between MDD and onset of SI and SA is likely due to its time-varying nature (i.e. the requirement for it to have occurred prior to onset of SI and SA) as a lifetime history of MDD (i.e. occurring before, after or in the same year as SI or SA) resulted in highly significant risk-related associations (OR = 5.31 – 6.10; not shown). Early substance use was not associated with onset of SI. However, across several analyses, there was substantial evidence for interactions of early substance use with sex and race (Table 4). While the main effect of early substance use was not strongly related to onset of SI or SA, males
