Abstract
BACKGROUND: Binge drinking has been linked to neurocognitive disadvantages in youth, but it is unclear whether drinking at particularly heavy levels uniquely affects neurocognitive performance. This study prospectively examined (1) whether initiating moderate, binge, or extreme-binge drinking in adolescence differentially influences subsequent learning and memory performances, and (2) whether dosage of alcohol consumption is linearly associated with changes in learning and memory over 6 years of adolescence. METHODS: Participants, who later transitioned into drinking, were administered verbal learning and memory (VLM) assessments at project intake prior to the onset of substance use (age 12 to 16 years), and at follow-up approximately 6 years later (N = 112). Participants were grouped based on alcohol involvement at follow-up as follows: moderate (≤4 drinks per occasion), binge (5+ drinks per occasion), or extreme-binge (10+ drinks per occasion) drinkers. RESULTS: Despite equivalent performances prior to onset of drinking, extreme-binge drinkers performed worse than moderate drinkers on verbal learning, and cued and free short delayed recall (ps < 0.05); binge drinkers did not differ from the other groups. No distinct thresholds in alcohol quantity to differentiate the 3 groups were detected, but estimated peak blood alcohol concentrations were linearly associated with verbal learning (β^ = -0.24), and immediate (β^ = -0.27), short delay free (β^ = -0.28) and cued (β^ = -0.30), and long delay free (β^ = -0.24) and cued (β^ = -0.27) recall (ps < 0.05). CONCLUSIONS: Drinking quantity during adolescence appears to adversely affect VLM in a dose-dependent manner. The acquisition of new verbal information may be particularly affected, notably for those who initiated drinking 10+ drinks in an occasion. Although classification of drinkers into categories remains critical in the study of alcohol, it is important to consider that subtle differences may exist within drinking categories.