Chai Rin Kim

A smoker’s chances of developing a nicotine dependence may be determined by genetics, suggests a recent study published in the journal “Translational Psychology.”

The study, co-authored by Yale School of Medicine psychiatry professor Joel Gelernter determined that nicotine dependence can be associated with variants in a particular gene: CHRNA4. The study — the largest to date investigating the genetics of nicotine dependence — provided statistical evidence for the link between CHRNA4 and nicotine addiction. Study authors and experts on nicotine dependence said that by identifying the genetic cause of nicotine dependence, the research has potential to assist in the development of smoking-cessation treatment.

“This study, for the first time, was able to … provide very strong statistical evidence that indeed the variants of [CHRNA4] are associated with nicotine dependence,” said Dana Hancock, study author and genetic epidemiologist at Research Triangle Institute International.

Hancock and her fellow researchers began by assembling a cohort of 17,074 smokers of European descent. Next, they collected data about study participants’ nicotine dependence by asking not only how often they smoked, but also under what conditions. Hancock added that including questions such as “How early in the morning do you smoke?” or “Do you still smoke while you’re ill?” allowed researchers to assess subjects’ smoking dependence, as opposed to just smoking patterns.

When the researchers compared the results of these surveys to the smokers’ genomes, they found that smokers with a particular variant of the CHRNA4 gene had an increased risk of developing nicotine dependence by about 10 percent. Though the findings of previous studies have strongly suggested that CHRNA4 is responsible for nicotine dependence, none had been able to provide definite statistical evidence, Hancock said. The larger sample size made the study results confirming that CHRNA4 plays a role in nicotine dependence more significant and definitive than the results of previous studies.

“This study raises the possibility of developing treatments for nicotine dependence that selectively act at nicotine receptors that contain the [CHRNA4 gene variant],” said John Krystal, Yale School of Medicine psychiatry department chair.

According to Krystal, the study’s findings allow for the development of more precise methods to aid smokers in the process of quitting. By targeting a specific gene, the research also guides future treatment development for nicotine dependence, he added.

However, Caryn Lerman, co-director of the Penn Medicine Neuroscience Center, said further research needs to be conducted before the study’s findings can be applied for the development of further nicotine-dependence treatments.

“It’s conceivable that the genetic regulatory mechanism could be targeted [for treatment], but the next steps would be to validate the findings,” Lerman said.

Lerman, whose primary area of research is the genetics of smoking cessation, added that eventually this research may contribute to the development of medications that target the CHNRA4 gene.

Still, Hancock said that she hoped the study would spur further research in the field of nicotine addiction, with the intention of ultimately of reducing the public health effects of smoking.

“Our ultimate goal, [is] to reduce the risk of the public health burden on cigarette smoking,” she said.

According to the Centers for Disease Control and Prevention, nearly 18 of every 100 U.S. adults 18 years or older currently smoke cigarettes.