swirling smoke

Struggling to Quit Smoking? Your Genes Might Be at Fault

How environment, behavior and genetics affect nicotine dependence

Your Health

November 18 is the Great American Smokeout.

At 15-years-old, Melinda Fenick tried her first cigarette in the girl's bathroom of her high school. By her senior year, she was smoking a pack of cigarettes a day, and Fenick then spent more than two decades struggling with tobacco addiction. She craved cigarettes from morning to night, thanks to nicotine, a highly addictive chemical compound found in tobacco.

Over the years, she tried several different ways to quit smoking. She used nicotine chewing gum and even took a nicotine-free prescription pill that would purportedly help her quit smoking. At one point, Fenick worked for the commonwealth of Virginia, which paid for her to go through a smoking cessation program three times — to no avail; she couldn't shake the habit.

"I was like, seriously, I've tried everything, and I can't do this anymore," Fenick, 42, said. "So I put it on the back burner, and then I went several years without trying to quit because there was no hope."

The American Cancer Society estimates about 34 million American adults smoke cigarettes; they also say smoking remains the single largest preventable cause of death and illness in the world.

Why is smoking so hard to stop?

Nicotine is so addictive, according to Dr. J. Lee Westmaas, the scientific director for behavioral research at the American Cancer Society, because of how it affects the brain.

"[Nictone] impacts levels of serotonin and dopamine in the brain, which are neurotransmitters involved in feelings of pleasure, appetite, sleep, and other important functions," Westmaas said. "Consuming nicotine causes a release of dopamine, which is central to invoking the reward pathways of the brain."

According to Westmaas, there are many reasons why it can be challenging for some people to quit smoking. For example, if a person has smoked for a long time, they are likely more dependent on nicotine. As a result, they may experience more intense withdrawal symptoms, resulting in smoking again to relieve those symptoms. Also, a person's social or physical environment could affect whether they are able to quit.

But despite smoking being a hard habit to break for so many, for others, it's as simple as quitting cold turkey. And a group of researchers believes much of this has to do with genetics.

Victoria Risner was the primary researcher on a study conducted by psychologists at Emory University and published by Nicotine & Tobacco Research that examined the genetic risk of nicotine dependence.

Risner, currently a medical student at the University of North Carolina at Chapel Hill, analyzed a collection of data for months; the data contained information about people with various traits, genes and disorders that lead to other addictions. Next, Risner and her fellow researchers looked for matching variants in genetic data from a national representative sample of Americans diagnosed with nicotine dependence. At the end of the study, the results showed how different traits and disorders raised or lowered the risk of nicotine dependence.

"A couple of our phenotypes (a phenotype is the set of observable characteristics or traits of an organism) were substance use-related," Risner explained. "We include alcohol use disorder, but we also included some phenotypes that are not related to substance use, like neuroticism, which is a personality trait often associated with anxiety disorders, depression, as well as schizophrenia."

"And the reason we used these traits is that there's been previous research that has indicated that those phenotypes have a genetic underpinning and are correlated with nicotine dependence. Because of this, you can assume via that relationship, that there are shared genetic variants that can contribute to both diseases," Risner said.

The study concluded that those with a higher risk of diseases and conditions like schizophrenia, depression, self-reported risk-taking, and even high body mass index were all indicators of a higher risk for nicotine dependence.

"Obviously, there are going to be some environmental effects for somebody's risk for developing nicotine dependence," Risner said. "For example, you have to initiate using some nicotine product. Still, there are a lot of genetic underpinnings on who actually goes on to develop an addiction, and I think that's really important for destigmatizing addiction in general. Especially with nicotine dependence," Risner said.

Risner and her fellow researchers hope their study helps boost the understanding of nicotine dependence and that other researchers build off their model. They also dream of the day when clinicians can provide a genetic test to assess a person's risk for nicotine dependence.

The health effects of smoking

Smokers put their health at risk every time they light a cigarette. According to the Centers For Disease Control and Prevention, smoking can cause cancer, heart disease, stroke, lung diseases, diabetes and chronic obstructive pulmonary disease (COPD), including emphysema and chronic bronchitis. Smoking causes about 20% of all cancers and about 30% of all cancer deaths in the United States. Smoking also accounts for as many as eight out of 10 COPD-related deaths.

These troubling stats are why experts in the industry encourage smokers to quit. But because of genetic and environmental differences among people, there is no one-size-fits-all solution for stopping smoking. Instead, there are prescription medications smokers can take to lessen their cravings and help with nicotine withdrawal. Risner says there are also more therapeutic ways to try to quit, such as support groups and therapy.

Fenick finally quit tobacco for good in 2020 after she was diagnosed with a blood clot in her leg; doctors said part of the reason the clot developed was her excessive smoking. She encourages other smokers not to wait until a health issue arises and to stop the deadly habit once and for all.

"I wish I would have never picked up a cigarette ever," Fenick said. "And that's why I tell my daughter, who's now 15, don't even try it. It'll be the worst mistake of your life."

Resources
American Cancer Society
Smokefree.gov
American Lung Association

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