The results of this study, however, suggest that this threshold is not reached frequently enough to challenge the validity of P300 amplitude as an endophenotype when applied to community populations. Similarly, the results of this study may not be easily generalized to populations selected for particularly early alcohol consumption, as only 1.7% of our sample reported an intoxication by age 11. Additionally, this study only examined AAU up to approximately age 18. Our results may have been different had we examined the effects of cumulative alcohol use on P300 amplitude at an older age.
