Alcohol consumption during adolescence alters brain development trajectories
Adolescents appear to have disordered normal brain growth trajectories after initiating drinking, with or without co-use of marijuana, a recent study has found. Peak consumption in the past year and family history of alcoholism possibly contribute to abnormal cortical volume trajectories.
Gray matter volume among no/low drinkers decline throughout adolescence and slowed in many regions in later adolescence. Such declines were complemented by white matter regions growing at faster rates at younger ages but slowing toward young adulthood.
Initiation of heavy drinking in youths resulted in an accelerated frontal cortical gray matter trajectory, divergent from the norm. There were no significant effects on trajectories among moderate drinkers, but their intermediate position between no/low and heavy drinkers suggested a dose effect.
Furthermore, marijuana co-use and baseline volumes did not contribute significantly to the alcohol effect, according to the authors.
In this large national, multisite, prospective study, a total of 483 adolescents (ages 12–21 years) were analysed before initiation of drinking, and at 1 and 2 years later. There were 356 participants who continued to meet the study’s no/low alcohol consumption entry criteria, 65 who had initiated moderate drinking and 62 who had started heavy drinking at the 2-year assessment.
The authors used magnetic resonance imaging to quantify regional cortical and white matter volumes. Percent change per year in adolescents who continued to meet no/low criteria served as development control trajectories against which to compare those who initiated moderate or heavy drinking.