A single episode of heavy drinking in emerging adulthood may be associated with immediate structural changes of the corpus callosum, according to results of a prospective study published in Alcoholism: Clinical and Experimental Research.

Emerging adulthood is a critical neurodevelopment period in which extreme drinking, that is often socially encouraged or tolerated, has a potentially pronounced neurotoxic impact. Though studies have shown heavy alcohol use in emerging adults to be associated with structural brain damage, the extent to which a single extreme drinking episode affects brain morphometry has not yet been determined.

To assess this, data from 50 individuals (52% women) before and after celebrating their 21st birthday were analyzed. MRI data from three sessions were compared. The baseline session occurred an average of 11 days before the 21st birthday celebration, the second was issued an average of 3-4 days after the 21st birthday celebration, and the final MRI was taken 5 weeks post-birthday celebration to examine the stability of any post-birthday structural changes. Participants completed a semi-structured interview to assess alcohol consumption and other substance use during their 21st birthday celebration.

The average peak estimated blood alcohol content (eBAC) for participants with complete data was 0.23 g/dL. Approximately 44% of participants achieved peak eBACs of >0.25 g/dL. Higher 21st birthday peak eBAC was associated with significantly decreased mean volume of the posterior subregion of the corpus callosum relative to baseline (P =.016). 29 individuals returned for the third MRI 5 weeks after their birthday celebration. After 5 weeks, peak eBAC was not significantly associated with further changes or recovery in the morphometry of the corpus callosum or its subregions.


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The results from this study showed that even a single event of heavy drinking during emerging adulthood can significantly impact the volume of the posterior corpus callosum. These changes remained significant even when accounting for lifetime alcohol use and lifetime cannabis use. Communication of this information to individuals before their 21st birthday may make them aware of the potential danger of these events.

Limitations to this study include the small number of participants, the short duration of the study, and the retrospective self-report on drinking behavior. The eBACs also did not take into account how much food was consumed or any occurrence of vomiting, which may have led to overestimates of eBAC. Future research should include larger sample sizes, should analyze segmented hippocampal data, and use more accurate methods of BAC estimation. Future studies investigating the mechanics of these neuromorphometry are warranted.

Reference

Hua JPY, Sher KJ, Boness CL, et al. Prospective study examining the effects of extreme drinking on brain structure in emerging adults. [published online September 24, 2020]. Alcohol Clin Exp Res. doi: 10.1111/acer.14446