We all know people who, despite best intentions and tons of counseling, smoke-stopping treatments, and patches—can’t quit smoking. So, are genes in play?
Absolutely, say experts. But it takes two to tango: Inherited genes combine with the environment we live in to determine nicotine dependence—and, of course, each of us has varying degrees of willpower. “All addictive behaviors and diseases have a genetic and an environmental basis and about half of the total variance in tobacco-use can be attributed to genetics,” says tobacco researcher Stephen Jay, M.D., professor of medicine and public health at Indiana University School of Medicine.
Studies show that people with a trio of altered nicotine-receptor genes are primed for nicotine dependence and heavy smoking. But with the mutation comes a silver lining, of sorts: New research shows those with the high-risk genes are more likely to quit with smoking cessation medicines and nicotine replacement therapies compared to those on placebo, according to the May online issue of The American Journal of Psychiatry.
More than 46 million Americans continue to smoke. Fifty million-plus have quit. Today’s treatments are scientifically sound and worth a try, but more research will produce better approaches to prevent and treat addictions, urges Dr. Jay.
“We are at the dawn of research into the relative contributions of genes and the environment in determining health—whether of our family, pet dog, a garden rose, or a mountain gorilla. From this research will come better ways to prevent and treat addictive behaviors and diseases. But when we can accomplish these ends depends upon how America chooses to spend its treasure. Greater investment in health related research over the next 15 years will bring us to the finish line sooner than if we continue our current level of funding support.”
On the Horizon: A Gene Vaccine for Smokers?
Early findings suggest a shot that blocks the actions of nicotine in the body may be a powerful new ally for smokers who want to quit.
In the journal Science Translational Medicine, researchers at Weill Cornell Medical College describe how a single dose of their novel vaccine protects mice, over their lifetime, against nicotine addiction. The vaccine is designed to use the animal’s liver as a factory to continuously produce antibodies that inactivate nicotine when it enters the bloodstream, preventing the chemical from reaching the brain.
“As far as we can see, the best way to treat chronic nicotine addiction from smoking is to have these Pacman-like antibodies on patrol, clearing the blood as needed before nicotine can have any biological effect,” says the study’s lead investigator, Dr. Ronald G. Crystal, chairman and professor of genetic medicine at Weill Cornell Medical College. “While we have only tested mice to date, we are very hopeful that this kind of vaccine strategy can finally help the millions of smokers who have tried to stop, exhausting all the methods on the market today, but find their nicotine addiction to be strong enough to overcome these current approaches,” he says.
The researchers are preparing to test the nicotine vaccine in rats and then in primates—steps needed before it can be tested ultimately in humans.
Key Genetic Discoveries
Tobacco Addiction: Family and twin research studies over the past 50 years show genes influence tobacco addiction—a finding that molecular genetics now confirms. Multiple studies identify genes that are consistently associated with nicotine dependence and the amount smoked.
Nicotine Dependence: A February 2012 study supports earlier findings that chromosome 20 harbors genetic variants that influence nicotine dependence in Finnish adult smokers.
Smoking Cessation: Data suggest that tobacco abstinence is partly related to heritable “quit/success” genes.
—Dr. Stephen Jay