Is Teenage Drinking as Harmless as it Seems?

Think back to your youthful, adolescent years. A time that was free from most of the pressures and burdens that come with being on your own in the real world.  A time when you were old enough to have achieved some independence yet still (hopefully) living rent free at your parents. Along with this life stage might have also came an overwhelming sense of invincibility. Or was that just me? Regardless, it is probably not difficult to imagine that most adolescents do not burden themselves with the consideration of both short term and long term consequences of their actions. And when it comes to experimenting with consuming alcohol, this scenario is certainly no exception. According to statistics from the Center for Disease Control, in a 2017 youth risk behavior survey it was found, 30% of high school students consumed alcohol during the past 30 days, and 14% of those students binge drank. Aside from the already endless list of risks that come with adolescent alcohol consumption, and as if parents of high school aged kids needed on more reason to crack down on adolescent drinking, Jamie Rointman now provides evidence to suggest that alcohol consumption during this stage of development could lead to lasting physiological brain changes that make one more prone to risky behavior.

In the article “Consequences of Adolescent Ethanol Consumption on Risk

Preference and Orbitofrontal Cortex Encoding of Reward,” Jamie Rointman and her colleagues set out to determine how activity in the prefrontal cortex might be altered due to adolescent alcohol consumption, and how this altered activity may manifest as changes in risk preference later on. To do so they measured the risk preference of rats while also monitoring populations of neurons in the orbitofrontal cortex. Adolescent rats were given daily access to alcohol in a form analogous to a Jell-O shot. After adolescence the rats were no longer given access to alcohol. The risk assessment the rats were evaluated by involved one pellet dispenser that provided a small reward 100% of the time, and another pellet dispenser that provided a large reward at varying probabilities. The latter dispenser was the more risky option due to the fact a reward in the form of alcohol infused Jell-O was only presented 12.5%, 25%, or 50% of the time. Of the 12 rats that were given daily access to alcohol, half consumed a large amount of alcohol, and half consumed a lower amount of alcohol. All the rats selected the risky lever less frequently as the probability of a reward being presented decreased, indicating they were sensitive to the probability changes in reward distribution. However, the rats that consumed a large amount of alcohol during adolescence showed a significantly higher preference for the risky lever when compared to the low consumption and control groups regardless of the probability that they would actually receive the reward. Additionally, the animals that showed a high risk preference also had reduced responses to rewards in a population of neurons within the orbitofrontal cortex. These results taken together suggest that adolescent alcohol intake likely results in altered development in the orbitofrontal cortex thereby causing an increased preference for large, risky rewards over small, certain rewards past the adolescent stage and period of consumption. Now at this point you are probably thinking (and hoping) that the detriments of teenage alcohol consumption stop there. Well unfortunately, you would be wrong.

An article published in “Times” magazine discusses another study that found there are additional consequences to consumption of alcohol during adolescence as well as additional brain regions affected. Where as the previous study looked more broadly at the effects of voluntary consumption during adolescence in rats, this study deliberately tried to mimic a binge drinking condition in rats, which is a common method of consumption amongst teens. To do so, a population of rats was given alcohol for two days in a row, followed by two days of no alcohol. For a period of two weeks this alternating two-day treatment pattern continued. Surprisingly enough, for the rats that were studied into adulthood, researchers found that those exposed to the binge drinking treatment during adolescence actually preferred alcohol over water. So essentially this binge drinking induced signs of alcoholism in adulthood. The researchers suggest that this alcoholic behavior is most likely due to the depressed synaptic activity in the amygdala that results as a consequence of adolescent binge drinking, since the amygdala has been previously shown to be involved in the development of alcoholism. Finally, researchers also found that these same rats exhibited more anxiety-like behaviors than those that did not binge drink in adolescence. The researchers suggest this shift in behavior might actually be due to changes in the actual DNA of the rats as well as in specialized proteins called histones. Histones are cellular structures found in eukaryotic cells that are responsible for the packaging of DNA into structural units. They also have a role in gene regulation. In summary, researchers found evidence to suggest intermittent alcohol exposure during adolescence causes long-term effects in histones and depressed neural activity in the amygdala.

The first study discusses how voluntary alcohol consumption in adolescent rats may lead to more risky behavior further down the road as well as alter orbitofrontal development. These results may help further explain the risky behavior that all too often accompanies consumption in young people such as drinking and driving, drinking in excess, unprotected sex, etc. The second study takes this a step further and specifically replicates the consumption method often seen in teens, which is binge drinking, and discusses how this may lead to increased behaviors of anxiety as well as depressed activity in the amygdala. These results may help further explain the underlying mechanism that leads to the alcoholic condition. Both studies dealt with providing rats with alcohol during adolescence and both studies found evidence to suggest that alcohol consumption during this developmental period correlates with neurological changes in the brain as well as behavioral changes. Not only are these effects detrimental to neural development but there is also evidence from both studies to suggest they are long lasting well into adulthood. Considering these results, it would be safe to conclude all teens are better off abstaining from underage drinking, especially during a time when their brain and body are still developing. Together, these studies demonstrate that the consequences of alcohol consumption during adolescence span much further than a hangover and the risk of an underage drinking ticket.

References

Times Magazine. “What Binge Drinking During Adolescence Does to the Brain.”

3 April 2015.

http://time.com/3770755/binge-drinking-adolescence-brain/

Pandey, Subhash C et al. “Potential role of adolescent alcohol exposure-induced amygdaloid histone modifications in anxiety and alcohol intake during adulthood”  Neurobiology of disease vol. 82 (2015): 607-619.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4581895/

McMurray, M>S., Amodeo, L. R., & Roitman, J. D. (2015). Consequences of Adolescent Ethanol Consumption on Risk Preference and Orbitofrontal Cortex Encoding of Reward. Neuropsychopharmacology, 41(5), 1366-1375.
doi:10.1038/npp.2015.288

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