Altered Brain Developmental Trajectories in Adolescents After Initiating Drinking

Abstract

Objective: 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.

Method: 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.

Results: 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.

Conclusions: 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.

Keywords: Adolescents; Alcohol Abuse; Brain Imaging Techniques.

Figure 1.

Left: Plots of 356 adolescents who continued to meet no/low criteria with connected baseline, 1-year, and 2-year follow-up values (boys in blue, girls in red) plotted as a function of their baseline age for frontal gray matter volume (top) and the central white matter sample volume (bottom). The lmer fits with +/− 1 and 2 SD separately computed for boys (blue) and girls (red) are also plotted. Note that the frontal lobe values decrease fairly linearly, whereas the growth in the white matter volume slows over age. For both regions, boys had larger volumes than girls. Right: The same data as above but adjusted for variation in supratentorial volume (svol), which attenuated sex differences in regional volumes.

Figure 2.

The figures of the brain note the regions-of-interest (ROI) measured. The slope of regional gray matter volumes (top 6 scatter plots) and white matter volumes (bottom 3 scatter plots) for each of the 356 participants in the continuing no/low drinking group (boys in blue, girls in red) with slope over age linear regression lines for each sex plotted separately. Below each scatter plot is a bar graph displaying the average slope for each of the three initial recruitment age groups (12-14.9, 15-17.9, 18-21.9 years old).

Figure 3.

Plots of connected baseline, 1-year, and 2-year follow-up values for 356 adolescents who continued to meet no/low criteria (gray) and 62 heavy drinkers (green) as a function of baseline age with lmer fits with +/− 1 and 2 SD computed separately for no/low (gray) and heavy drinkers (green) superimposed for frontal, occipital, cingulate, and total gray matter volume.

Figure 4.

Bar graphs of mean slope and 95% confidence interval for heavy (green), moderate (orange), and continuing no/low (gray) drinking groups for each regional volume measured.

Figure 5.

Lateral (top) and medial (bottom) view of the left hemisphere with color scale showing regions where heavy drinkers have significantly steeper reduction in gray matter volumes than no/low drinkers. Regions showing faster cortical volume declines in the heavy drinkers relative to the no/low drinkers displayed in bright orange are FDR-corrected (p<.025).

Figure 6.

Scatter plots, Pearson r, and Spearman Rho of slopes vs. maximum drinks per year for parietal regions of interest with heavy drinkers in green and moderate drinkers in orange.