Smoking Addiction Linked to Brain Defect, Study Shows

Researchers have uncovered one of the secrets of nicotine addiction, which could lead to breakthrough technologies and treatments to help smokers quit, according to a study released Sunday by Nature online.

Scientists at the Scripps Research Institute in Florida have pinpointed a brain pathway that aids in regulating our desires to smoke. When the receptor functions normally, consuming nicotine triggers a message to the brain which dampens further urges.

The team found that when rats were genetically modified to alter the receptor function, the amount of nicotine they consumed escalated greatly -- their brain wasn’t getting the “stop” message. The researchers noted that similar genetic variations existed in humans giving them a potential predisposition for cigarette addiction.

"Our data probably explain the fact that individuals with this genetic variation have increased vulnerability to developing tobacco addiction," Kenny told the AFP. "They are likely to be far less sensitive to the averse properties of the drug, and are thus more likely to acquire a nicotine habit."

Roughly one-third of the U.S. population is believed to have a form of the gene that leads to greater cravings, putting them at risk for one of the leading causes of death in the country. Cigarette smoking accounts for 1-in-10 adult deaths and is the reason for 9-out-of-10 cases of lung cancer.

"This study has important implications for new approaches to tobacco cessation," said University of Pennsylvania neuroscientist Jon Lindstrom, who has investigated other nicotine receptors in the brain and will participate in the follow-up research, in an interview with the AFP.

Current cessation strategies focus on patches, which boost reward but are also intrinsically addictive. New drugs could help eliminate the craving altogether. "Restoring or increasing the aversion to high doses of nicotine may complement these approaches and increase their efficacy, or replace them," Lindstrom said.