Alcohol dependence may be genetic

Alcohol Problems: New Risk Genes Uncovered

Some have their alcohol consumption well under control - others, on the other hand, consume problematic amounts. In addition to personal circumstances, genetic predisposition also plays a role in this tendency, as a study has now documented: the scientists have added 19 more to the ten known genetic risk factors known to date, which may include candidates for drug development. The results also show a common genetic basis between the tendency to abuse alcohol and other neuropsychiatric problems in humans.

It is a personal and social problem of enormous importance: In extreme cases, alcohol consumption can lead to physical and mental dependence with fatally destructive power for those affected and their environment. But even without addiction, excessive consumption can be associated with numerous negative effects, as numerous studies have shown: Excessive alcohol consumption is one of the most important causes of illness, early death and social problems worldwide.

A complicated mixture of a person's individual living conditions and their predispositions is considered to be the cause of the development of alcohol problems. Scientists have already devoted themselves to studying the genetic aspects. From these studies it was clear: THE alcoholic gene does not exist - the hereditary component of tendency, on the other hand, seems to be based on a complex mixture.

Tracking down genetic factors

So far science has known ten risk genes associated with alcoholism. An international team of researchers has now started looking for additional factors to further explore the importance of genetics in the alcohol problem. To this end, you carried out a so-called genome-wide association study. The aim of this approach is to identify certain types of genes that coexist with a certain trait. In the current case, this meant that the researchers wanted to determine which gene variants occur more frequently in participants with problematic alcohol consumption than in the general population.

"For this type of investigation you have to have access to a very large amount of DNA material in the form of the complete genetic profiles of several hundred thousand people," says co-author Mette Nyegaard. "In our case it was the data from a total of 435,000 people". They come from three databases which, in addition to the genetic sequences, also contain detailed information about the health and lifestyle of the participants. In some cases there was a diagnosed alcohol problem. In other cases, the researchers were able to use survey information to identify which people have alcohol consumption that is likely to cause psychological, social and health damage.

As the researchers report, the evaluations revealed 29 genes that seem to be linked to problematic alcohol consumption. 19 of them are new, the others were those previously identified and could thus be confirmed. The new candidates also include genes that suggest a function in the brain or nervous system - such as a genetic makeup that is responsible for the development of a receptor for the neurotransmitter dopamine. The newly identified risk genes now offer new insights into the biological mechanisms involved in the development of problematic alcohol consumption, the scientists summarize.

It is hoped that in the long term these findings will help develop new drugs to treat alcohol addiction. The scientists say that it remains to be seen which of the candidates are suitable as starting points. In principle, however, there is already potential: some of the risk genes are known to be linked to functions that can be influenced by known drugs.

Common genetic bases are emerging

As part of their study, the scientists also compared the pattern of alcohol risk genes with that of other neuropsychiatric characteristics or disorders. It was shown that, from a statistical point of view, those who have problematic alcohol consumption also often have a genetic predisposition for the development of depression, anxiety disorders, ADHD and insomnia. The tendency is also closely linked to substance abuse and smoking, according to the evaluations. “We are now beginning to see the outline of a genetic architecture: some form of relationship between alcohol abuse and other substance abuse - and between alcohol abuse and psychiatric disorders. In other words, there's arguably a fundamental genetic component involved, ”says Nyegaard.

In conclusion, however, the scientist emphasizes again that genetic predispositions are only one component in the complex developmental history of psychiatric difficulties and alcohol problems. “Our study results show once again how important a person's environment is,” says the scientist.

Source: Aarhus University, article: Nature Neuroscience, doi: 10.1038 / s41593-020-0643-5

June 8, 2020

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