For some people the first puff of smoke they tried felt repulsive while for others those puffs came with a rush of pleasure. Researchers have identified a gene variant that may help explain why some smokers get addicted from their first cigarette while others seem immune to the addictive properties of tobacco.

The paper published online in the journal Addiction reports an association between a variant in the nicotine receptor gene CHRNA5, initial smoking experiences and current smoking patterns. This gene is far more common among smokers than in those who have the occasional cigarette.

Study senior author Ovide Pomerleau of the University of Michigan Medical School says in a statement say the genetic make up, coupled with environmental factors and social pressures help determine how people get addicted to smoking for the rest of their lives.

Researchers at the University of Michigan, Washington University School of Medicine in St. Louis and University of North Carolina in Chapel Hill used genetic and smoking data from 435 volunteers. Some of whom were regular smokers and some who had tried cigarettes but were not currently smokers.

The results indicated that regular smokers were far more likely than non-smokers to have a less common form of the CHRNA5 gene. Scientists are hoping that by cracking the genetic codes, they could make it easier for people to de-addict or even not try cigarettes at all.