40 participants in the second study (none of whom were involved in the first) had a baseline scan before any significant AU (aged 12–16 years) and a follow-up scan approximately 3 years later (aged 15–19 years). Participants were part of a larger, longitudinal study, so researchers were able to select 20 AU youth (defined as alcohol initiators who had started heavy drinking; 6 females) and 20 non-AU youth (demographically-matched non-drinkers; 6 females). No significant group differences in performance were observed, nor were there significant group-by-time interactions in behaviour. There was a group-by-time interaction in two ROIs: the inferior parietal lobule and left MFG. At time 1, prior to consumption of alcohol (baseline), future AU youth showed less activation than future non-AU youth in both regions. At time 2 (3 years after the initiation of alcohol consumption in the AU youth), AU youth showed increased activity whereas non-AU youth exhibited decreased activity in both regions.
