Smoking: Gene makes it difficult to stop

Researchers are discovering the connection between gene variation and dissolution success

It is harder for some to stop smoking than others. © Tonkovic / thinkstock
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The genes are to blame - maybe researchers have discovered why some smokers find it harder to quit than others: a particular gene variant could make it harder to shake off nicotine addiction and become a nonsmoker. The reason: This gene regulates the amount and density of dopamine receptors in the reward center of the brain - and thus important regulator of nicotine addiction.

There is no shortage of reasons to stop smoking: smoking not only promotes lung cancer and cardiovascular diseases, it also damages sperm, promotes tooth loss, rheumatism and makes analgesics and narcosis worse. In addition, studies show that many of the negative consequences return when you become a non-smoker - so it's worth it.

Search in the dopamine system

But quitting smoking is anything but easy. After all, you fight against an addiction - and not everyone is successful. However, this is not only the strength of will responsible: "Twin and family studies show that smoking behavior is influenced by both genetic and environmental factors, " explain Yunlong Ma of Zhejiang University in Hangzhou and his colleagues. "The inheritance in terms of cessation is estimated at around 50 percent."

In other words, certain genes could influence whether nicotine withdrawal and the change to nonsmokers are easier or more difficult for us. Which genes are these has not been known. However, it seems natural to look for them in the reward system and the happiness hormone dopamine and its receptors, because they play a crucial role in addictions. "Variants in the genes that influence the concentration of synaptic dopamine probably also play a role in stopping smoking, " Ma and his colleagues said.

The researchers were found on the eleventh chromosome Koya79 / thinktock

Gene variant on the eleventh chromosome

One of these candidate genes on the eleventh chromosome, the DRD2 / ANK1 gene, has now been studied in more detail. It is one of the genes that influence the density of dopamine receptors in the reward center. For their study, the researchers evaluated genetic data from 9, 487 people of European descent and tested whether those who made changes to this gene became more successful non-smokers or not. display

In fact, researchers found that they found a statistically significant relationship between the Taq1 variant of the DRD2 gene and smoking success. Subjects with certain alleles of this gene were frequently successful nonsmokers than carriers of other variants. "Smokers with the Taq1A-A2 / A2 genotype are likely to be more likely to quit smoking than carriers of the A1 / A1 or A1 / A2 gene types, " the researchers report. Why this is so, is still unknown.

"Still in its infancy"

According to the scientists, this suggests that this gene might play a role in how easy it is for someone to resist nicotine addiction. If confirmed, this knowledge could help to help those in need. "Our findings thus provide solid evidence that it may be useful to use personalized, genotype-adapted strategies in smoking cessation, " Ma and colleagues said.

However, the researchers also emphasize that their results still need to be confirmed by further studies. "Research in this area is still in its infancy, as there are more, well-designed studies needed to elucidate the function of these genes, " said Ma and his colleagues. It could still be a bit early to use his genes as an excuse, if it has not worked out with the non-smoking. (Translational Psychiatry, 2015; doi: 10.1038 / tp.2015.176)

(Translational Psychiatrist, 02.12.2015 - NPO)