Adolf Pfefferbaum, M.D., Dongjin Kwon, Ph.D., Ty Brumback, Ph.D., Wesley K. Thompson, Ph.D., Kevin Cummins, M.A., Susan F. Tapert, Ph.D., Sandra A. Brown, Ph.D., Ian M. Colrain, Ph.D., Fiona C. Baker, Ph.D., Devin Prouty, Ph.D., Michael D. De Bellis, M.D., M.P.H., Duncan B. Clark, M.D., Ph.D., Bonnie J. Nagel, Ph.D., Weiwei Chu, M.A., Sang Hyun Park, Ph.D., Kilian M. Pohl, Ph.D., Edith V. Sullivan, Ph.D. Altered Brain Developmental Trajectories in Adolescents After Initiating Drinking. American Journal of Psychiatry. Online. http://ajp.psychiatryonline.org/doi/abs/10.1176/appi.ajp.2017.17040469
The authors sought evidence for altered adolescent brain growth trajectory associated with moderate and heavy alcohol use in a large national, multisite, prospective study of adolescents before and after initiation of appreciable alcohol use.
This study examined 483 adolescents (ages 12–21) before initiation of drinking and 1 and 2 years later. At the 2-year assessment, 356 participants continued to meet the study’s no/low alcohol consumption entry criteria, 65 had initiated moderate drinking, and 62 had initiated heavy drinking. MRI was used to quantify regional cortical and white matter volumes. Percent change per year (slopes) in adolescents who continued to meet no/low criteria served as developmental control trajectories against which to compare those who initiated moderate or heavy drinking.
In no/low drinkers, gray matter volume declined throughout adolescence and slowed in many regions in later adolescence. Complementing gray matter declines, white matter regions grew at faster rates at younger ages and slowed toward young adulthood. Youths who initiated heavy drinking exhibited an accelerated frontal cortical gray matter trajectory, divergent from the norm. Although significant effects on trajectories were not observed in moderate drinkers, their intermediate position between no/low and heavy drinkers suggests a dose effect. Neither marijuana co-use nor baseline volumes contributed significantly to the alcohol effect.
Initiation of drinking during adolescence, with or without marijuana co-use, disordered normal brain growth trajectories. Factors possibly contributing to abnormal cortical volume trajectories include peak consumption in the past year and family history of alcoholism.
Drinking during adolescence interrupts normal brain development and results in gray matter loss, new research shows.
A team of investigators associated with five US universities used MRI to analyze the brains of 483 youth and young adults (age, 12 to 21 years) before initiation of drinking and again 1 and 2 years later.
At the 2-year assessment, study participants who initiated heavy drinking were found to have an accelerated decline in their frontal cortical gray matter trajectories that was divergent from the norm.
"It may be particularly relevant that the alcohol's influence on brain structural development was significant for frontal regions, which are among the last to mature," she [Dr. Edith Sullivan] told Medscape Medical News.
"Damage to these regions can result in difficulties with problem solving, decision making, good judgment, appropriate social behavior, inhibition of inappropriate behaviors, and other actions associated with maturity," she said…
Previous research has identified abnormal growth patterns in youths who initiated and continued heavy drinking. However, moderate drinkers were excluded from these reports, "leaving unaddressed the question of whether highly prevalent, moderate drinking levels could interfere with normal developmental trajectories."…
The researchers note that the "dynamic growth pattern" in which gray matter volume declined and white matter volume grew in healthy participants through adolescence "formed the context for addressing whether and how initiation of moderate or heavy drinking altered components of these developmental trajectories."
Dr Sullivan noted that research suggests that the normal trajectory of loss of gray matter throughout adolescence "represents pruning of brain cells that we do not need or use." Youth who engaged in heavy drinking displayed an acceleration of this normal process.
"Importantly, through having a comparison group of no-to-low drinking youth, which enabled a quantitative measure of the expected normal rate of brain structural change, we could measure deviations from the norm in the drinking groups," she added…
"These interesting findings suggest that alcohol use, even infrequent use, during the teen years interrupts the way the brain matures, and it's particularly interesting that they found a dose-dependent effect, meaning that the more someone drank, the more they saw an effect on the brain."