Addiction is never easy to beat. In addition to physical withdrawal symptoms, social and emotional factors can determine how successful we are at stopping an addictive behavior.

Smoking and smoking-related diseases cause approximately 443,000 deaths annually in the United States, and smoking can prove to be one of the most difficult addictive habits to break.

Now, scientists have discovered that some addictions, smoking in particular, may be more difficult to overcome because of an addict's genes.

Studies On Smoking And Genetics

Three separate studies funded by European and the United States governments and published in Nature, the American Journal of Psychiatry and Nature Genetics, have discovered that one gene may make it more difficult to quit smoking, and increase the risk of cancer in patients.

The studies examined mostly smokers and ex-smokers, but also included a few hundred people who had never smoked. The researchers interviewed only people of European descent.

The Results

Researchers in the three groups found that smokers inherit the genetic code from neither, one or both of their parents. The study published in Nature Genetics found there are three separate genetic regions that affect cessation, addiction and the number of cigarettes smoked daily.

  • If smokers inherit the variant from one parent, they are one-third more likely to develop lung cancer. These smokers also smoke approximately one more cigarette per day than people without the genetic variant.
  • If smokers inherit the variant from both parents, they have a one in four chance of developing lung cancer, approximately 80 percent greater than those people without the variant. These smokers smoke two more cigarettes a day than those without the variant.

Differences Between The Studies

The three studies were conducted independent of one another. Two studies hypothesize that the genetic variant itself increases the likelihood of lung cancer and the progression of tumors.

One study, authored by Kari Stefansson of deCode Genetics in Iceland, hypothesizes that the increased levels of lung cancer are a result of more cigarettes smoked, and not the genetic variable itself.

Practical And Treatment Benefits Of These Studies

The authors from all three studies believe that these studies will help substance abuse counselors develop better smoking cessation programs.

Li-Shiun Chen, a researcher at the Washington University School of Medicine in St. Louis, explains that smokers with the genetic variants are more likely to stop smoking when they take smoking cessation medications, than when they attempt to quit without medical help.

Nora Volkow, the director of the National Institute on Drug Abuse, believes that with knowledge of these genetic variants, genetic testing and counseling can be performed to help people understand their increased likelihood of becoming addicted, developing lung cancer and other smoking-related diseases.

Stopping The Addiction

Though the percentage of Americans who smoke has decreased over the past 40 years, many people are still affected by smoking, whether they smoke themselves or are exposed to second-hand smoke.

These new genetic studies provide physicians with one way that they can help people avoid being addicted to smoking, as well as help them stop after they have started.