Early Drinking = Later Sickness: A Study In Twins

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Adolescents that start drinking early have been shown to have a much higher likelihood to become addicted later on. The alcohol itself may be responsible.

Maybe it’s a glass of wine at Christmas or a beer on your best friend’s birthday. At some point, most people start drinking alcohol. But while some take their first drink at 18, others start earlier, much earlier. There are kids who know what it feels like to be drunk when they’re 12 or 13.

But what does it mean when young people drink alcohol at an early age? Studies have shown that they later have more frequent problems with alcohol and other drugs or develop anti-social behavior. But the reason why is not really known. Scientists have now shown that it could be the alcohol itself that causes problems later on.

According to a study by the German Federal Centre for Health Education (BZgA) (1), 10 percent of 12- to 17-year-olds and 33.6 percent of 18- to 25-year-olds reported drinking alcohol regularly in 2015. According to the BZgA, only one in three people between the ages of 12 and 17 stated that they had never drunk alcohol.

There are many reasons why some young people start drinking early. Maybe you don’t know it any other way, because parents drink a lot, too. A wider environment also has an influence. When friends drink a lot, it’s hard to say no. After all, you want to belong, have fun, and have new experiences. The problem is that the earlier children and young people start drinking alcohol, the greater the risk of getting used to it, abusing it, or becoming addicted.

Scientists Daniel Irons, William Lacono, and Matt McGue of the University of Minnesota wanted to find out whether it is drinking itself that is responsible for it. For their study (2), they worked with more than 1500 twins and two scientific methods. The first tried to exclude as many outside factors as possible, which can also be responsible for the connection between early alcohol consumption and later addiction. Scientists also speak of disruptive factors. These include, for example, the drinking behavior of parents, social status, or mental disorders.

The second method compared twin siblings who started drinking at different times. One twin came into contact with alcohol at an early age, the other not. The scientists looked at the following: How do the siblings develop? Who grows up in a very similar environment? And, in the case of identical twins, do they have the same genetic make-up?

When the twins were 11 years old, the scientists were interested in those influences that could affect the relationship between early drinking and later problems, in addition to alcohol itself.  At the age of 14, the twins stated whether they had ever drunk alcohol or had ever been drunk.  At the age of 24, they focused on drinking habits, the importance of other drugs, social behavior, commitment, or the relationship to the family.

When the researchers evaluated the data, they found that early drinking is indeed a direct cause of later problems with alcohol and other drugs. Even when the researchers calculated out the possible disturbing factors, the connection remained. However, the study says nothing about the mechanism behind it. One possibility, the researchers believe, is the damaging effect of alcohol on the developing brain of young people.

For example, American researcher Susan Tapert and her team have been able to show (3) that changes in the white matter through intoxication can already be detected in 16- to 19-year-olds. The prefrontal cortex seems to be particularly susceptible to change, taking on tasks such as planning, weighing, and adapting behaviour.

However, the analysis of the twins also shows that there may be other factors that can affect both early drinking and later problems. Genes also play a role in this. This would also fit in with previous studies, which have shown that the genome can also contribute to the tendency to drink a lot more. According to British researchers, anyone with the RASGRF-2 gene variant has a deeper feeling of satisfaction when drinking (4).

This is part 15 of a series covering twin health provided by Paul Enck from the Tübingen University Hospital and science writer Nicole Simon. Further studies in twin research can be found at TwinHealth website. Translation was done with the assistance of DeepL translator (www.deepl.com/translator)

References:

  1. http://www.bzga.de/presse/pressearchiv/?jahr=2016&nummer=1046
  2. Irons DE1, Iacono WG, McGue M. Tests of the effects of adolescent early alcohol exposures on adult outcomes. Addiction. 2015 Feb;110(2):269-78.
  3. McQueeny T, Schweinsburg BC, Schweinsburg AD, Jacobus J, Bava S, Frank LR, Tapert SF. Altered white matter integrity in adolescent binge drinkers. Alcohol Clin Exp Res. 2009 Jul;33(7):1278-85.
  4. Stacey D, Bilbao A, Maroteaux M, et al. RASGRF2 regulates alcohol-induced reinforcement by influencing mesolimbic dopamine neuron activity and dopamine release. Proc Natl Acad Sci U S A. 2012 Dec 18;109(51):21128-33.
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