As a further limitation, stress and alcohol use were assessed concurrently, using retrospective self-report measures, which creates vulnerability to reporting bias. In addition, our findings are correlational in nature and it is conceivable that rather than stress precipitating problem drinking, problem drinking is precipitating stressful life events. Even if the causality is reversed relative to our interpretation, this would not undermine the observation that individuals with greater divergence or mismatch between reward-related VS and threat-related amygdala reactivity are at increased risk. However, in this case risk would be redefined as an increased probability that problem drinking would result in the experience of more impactful stressful life events. In fact, it is possible that both causalities hold true, as stress arising from prior alcohol use could contribute to the maintenance and escalation of harmful drinking patterns, thus creating a vicious cycle.61 Larger developmental prospective longitudinal studies in at-risk and normative populations would afford the opportunity to establish risk trajectories and causality in a more definitive way.
