An alcohol interaction model was computed by adding an interaction term involving Substance Use Lifestyle × Effortful Control to the single-factor main effects model described previously. The interaction term between effortful control and the substance use lifestyle factor contributed significantly to predicting early-adulthood problematic alcohol use (unstandardized estimate = 0.90, SE = 0.44, p<0.05). Figure 2 also reveals the interaction between adolescent substance use lifestyle and effortful control, demonstrating that for those youth with low levels of exposure to an alcohol-use lifestyle, poor effortful control appears to more strongly predict future problematic alcohol use. For youth with higher levels of exposure to alcohol during adolescence, levels of effortful control did not appear to protect against problematic alcohol use in early adulthood. In fact, at very high levels of exposure to an alcohol-use lifestyle, higher levels of effortful control might even contribute to experiencing more problems with alcohol by early adulthood.
