Success Of Quitting Smoking Hinges On Genetic Variations
May 31, 2012

Success Of Quitting Smoking Hinges On Genetic Variations

Connie K. Ho for

Nature versus nurture has always been a highly debated question in the sciences. This discussion has been seen in a research project focused on smoking, where scientists determined that genetics can play a role in how patients respond to treatments. Researchers from the Washington University School of Medicine found that genes can show how smokers will respond to medication to quit the habit; they found that gene variations that make it difficult to stop smoking will also make smokers respond to nicotine-replacement therapy and treatments.

The study, published in a recent issue of the American Journal of Psychiatry, found that it could be possible to predict how patients respond to drug treatments for smoking cessation in the future based on the gene variations.

“Smokers whose genetic makeup puts them at the greatest risk for heavy smoking, nicotine addiction and problems kicking the habit also appear to be the same people who respond most robustly to pharmacologic therapy for smoking cessation,” explained senior investigator Dr. Laura Jean Bierut, a professor of psychiatry, in a prepared statement. “Our research suggests that a person´s genetic makeup can help us better predict who is most likely to respond to drug therapy so we can make sure those individuals are treated with medication in addition to counseling or other interventions.”

In the experiment, the scientists looked at data from 5,000 smokers who were involved in community-based studies as well as another 1,000 smokers who participated in a project focused on clinical treatment. The researchers examined the connection between participants´ ability to quit smoking successfully and genetic variations that had been related to dependence on nicotine and a habit of obsessively smoking. They found an interesting set of results in regards to those who had high-risk genetic markers.

“People with the high-risk genetic markers smoked an average of two years longer than those without these high-risk genes, and they were less likely to quit smoking without medication,” noted first author Dr. Li-Shiun Chen, an assistant professor of psychiatry at Washington University, in the statement.

Individuals who showed high-risk genetic variants in the clinical trial were three times more likely to respond to drug therapies that were designed to help people quit smoking.

“The same gene variants can predict a person´s response to smoking-cessation medication, and those with the high-risk genes are more likely to respond to the medication,” continued Chen in the statement.

Both Bierut and Chen believe the findings show that the genetic variations can help explain why smokers may be addicted to nicotine, as they studied the same genes that determined heavy response and an intense response to nicotine-dependence treatments.

“It´s almost like we have a ℠corner piece´ here,” remarked Bierut in the statement. “It´s a key piece of the puzzle, and now we can build on it. Clearly these genes aren´t the entire story – other genes play a role, and environmental factors also are important. But we´ve identified a group that´s responding to pharmacologic treatment and a group that´s not responding, and that´s a key step in improving, and eventually tailoring, treatments to help people quit smoking.”

For those who don´t have a successful response to the nicotine-dependence treatments, it is possible that they can look into obtaining counseling or therapies that are not drug-related.

“This is an actionable genetic finding,” commented Chen in the statement. “Scientific journals publish genetic findings every day, but this one is actionable because treatment could be based on a person´s genetic makeup. I think this study is moving us closer to personalized medicine, which is where we want to go.”