Is Alcoholism Genetic? Study on Rats Says Yes

Published on September 2nd, 2016

Everyone has a choice. Whether you come from a long line of hard alcoholics or from a long line of perfectly sober health-nuts, the choice to drink is the same. It’s a yes or no. As far as being predisposed to choose yes, and as far as what happens to you if and when you choose yes, there may not be much choice for you after all. Disclaimer: this is NOT to say that drinking can be justified by saying your parents drank. However, genetically speaking, how much of the choice is yours becomes complicated.

A study by researchers at Purdue and Indiana University recently concluded that there are “930 genes associated with alcoholism, indicating that it is a highly complex trait…” This puts alcoholism in the same category of sophistication as human height.

The Study

Human beings and rats don’t seem to have much in common. In fact, we are over 95% genetically identical to rats. We live in the same area, eat the same food, are both warm-blooded mammals, and even suffer from the same diseases. This is why rats are so often used in scientific experiments, and for the experiment at hand, this is no different.

The researchers started with two lines of genetically diverse rats: “one group that displayed classic clinical signs of alcoholism and another that completely abstained from alcohol.” William Muir was a genetics professor involved in the study, and he explained how over the course of decades, some of the rats compulsively drank alcohol, preferring it to water and even exhibiting withdrawal symptoms without it. Still, though, the results varied.

“Under the influence of alcohol, some rats became docile and fell asleep in a corner while others became aggressive,” said Muir.

The next step in the study involved taking 10 rats from each line and comparing their genetic makeups. The study revealed 930 genes associated with drinking to excess.

The Results

Of the 930 genes found to be related to alcohol abuse, “the vast majority” are located in what are known as genetic regulatory regions, as opposed to coding regions. Genes within the genetic regulatory region are essentially inherited, and represent the ‘nature’ side of nature versus nurture. Genes within the coding region are the opposite, are unique to the individual, and represent the ‘nurture’ side.

Because the majority of the 930 genes were found in the genetic regulatory region, there is a substantial genetic component to alcoholism. The next step for these researchers is to determine the relevance of the findings in humans.

What does this mean for treatment?

There is a plus side and a negative side to the study’s findings when it comes to alcohol abuse treatment. The negative side is that due to the complex genetic workings in the trait of alcoholism, creating a single drug to treat it is unlikely. As Muir said, “It’s not one gene, one problem…This trait is controlled by vast numbers of genes and networks. This probably dashes water on the idea of treating alcoholism with a single pill.”

However, the study revealed that the glutamate receptor signaling pathway, which is a connection of neurons in the brain partly responsible for reward, contains a large number of alcoholism-related genes. The researchers said this may offer a place to start for future treatment.

Anyone can become an alcoholic, whether or not he or she is genetically predisposed to becoming one. Up until now, genetics are only thought to make up about half of the risk for alcohol dependence. The rest is truly up to you.

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