To further assess whether the high VS-low amygdala neural risk profile is associated with a positive emotion enhancement/behavioral disinhibition pathway to problem drinking, we tested a similar moderated mediation model using delay discounting scores as a mediator (Figure 3). The model fit the data very well (χ2=9.639, df=9, p=0.3805; RMSEA=0.010, CFI=0.995). While delay discounting was marginally positively correlated with LESS (p=0.059), it did not mediate the relationship between LESS and AUDIT scores for any amygdala reactivity or VS activity values at the 95% confidence level. However, at the 92% confidence level, delay discounting was a more reliable mediator of the relationship between LESS and AUDIT scores for those with relatively high VS activity and low amygdala reactivity (parameter estimate=0.0311, SE: 0.0271, 92% CI: 0.0001–0.1031), than for those with the opposite combination of neural traits (parameter estimate=0.0204, SE: 0.0278, 92% CI: −0.0087–0.0960; Figure 4b).
