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Drinking in adolescence alters brain development

Initiating drinking during adolescence was associated with disordered brain growth trajectories, according to recent findings.

“Abnormal growth patterns were observed in two recent longitudinal studies of youths who initiated and continued heavy drinking,” Adolf Pfefferbaum, MD, of Center for Health Sciences, SRI International, Menlo Park, California, and colleagues wrote. “Moderate drinkers were excluded from these reports, however, leaving unaddressed the question of whether highly prevalent, moderate drinking levels could interfere with normal developmental trajectories.”

To assess altered brain developmental trajectories associated with moderate and heavy alcohol use, researchers evaluated 483 adolescents, aged 12 to 21 years, before initiation of drinking and 1 and 2 years after. At 2-year assessment, 356 participants continued to meet researchers’ no/low alcohol consumption entry criteria; 65 initiated moderate drinking; and 62 initiated heavy drinking. MRI quantified regional cortical and white matter volumes.

Gray matter volume declined throughout adolescence and slowed in many regions in later adolescence among participants with no or low drinking.

Further, white matter regions increased at faster rates at younger ages and slowed at young adulthood among participants with no or low drinking.

Participants who initiated heavy drinking exhibited increased frontal cortical gray matter trajectory, different from “the norm,” according to researchers.

Significant effects were not observed among moderate drinkers; however, researchers asserted their intermediate position between no or low drinkiers and heavy drinkers suggested a dose effect.

Co-use of marijuana and baseline volumes did not significantly influence the effects of alcohol.

“These results provide evidence that initiation of heavy alcohol drinking during adolescence can disrupt normal, differential growth trajectories of specific cortical gray matter regions. Although significant effects on brain volumetric trajectories were not observed in moderate drinkers, this group’s intermediate position between no/low and heavy drinkers on many measures suggests a dose or threshold effect,” the researchers concluded. – by Amanda Oldt

Disclosures: Pfefferbaum reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.