The study found that the enzyme, which is known to metabolise both the smoking cessation drug bupropion and nicotine, influences smoking cessation and is highly genetically variable in all ethnicities.
"This first study identifies a very common genetic variant (present in anywhere from 25 to 50 percent of world populations) that appears to affect the outcome of smoking cessation treatment," said Rachel Tyndale, Section Head of Pharmacogenetics at CAMH and lead researcher on the study.
He added that the results would have to be replicated.
Tyndale and his team executed genotyping on smokers for CYP2B6, which is a gene known to be highly variable and has an enzyme, which metabolise bupropion, nicotine and serotonin.
Later the participants were provided with either treatment of placebo or bupropion for ten weeks and this was followed up for 6 months.
The research project found that 45 percent of individuals with a specific variation of the gene benefited from bupropion treatment and maintained abstinence longer while they did poorly on placebo, with a 32.5 percent abstinent rate against 14.3 percent respectively.
In contrast, 55 percent of those with a different variant of the gene (wild type variant) had good abstinences rates on placebo and also gained no additional benefit from Bupropion, suggesting that no individual got benefit from getting treated with Bupropion.
This study is published in the journal of Biological Psychiatry.