Previous studies have found that a chemical called ‘dopamine’ acts as a reward system in the brain, giving drinkers what psychologists call ‘positive reinforcement’.
Changes or differences in parts of the brain that control decision-making and restraint have been implicated in substance use, but the exact locations remained unclear.
The research, conducted by a team of 17 scientists from both Shanghai and the UK, used functional magnetic resonance imaging (fMRI) to explore such differences.
The research, “showed that the abnormal connectivity of certain areas may be a factor attracting individuals to smoking and drinking”, Feng Jianfeng, team leader from the Institute of Science and Technology for Brain-Inspired Intelligence affiliated with Fudan University.
The study found that regular smokers have low overall functional connectivity, especially in the brain area associated with the processing of punishment, while those who drink high amount of alcohol often have high brain connectivity, especially in the reward-related area of the brain.
The findings, published in British biomedicine journal eLife, showed the low functional connectivity is between two brain regions, namely the lateral orbitofrontal cortex and inferior frontal gyrus.
Weaker connection involving the two regions may, “make people more impulsive and less able to resist smoking,” according to the research.
Conversely, those who drink alcohol had high overall functional connectivity, specifically linked to reward-related systems, including the medial orbitofrontal cortex and the cingulate cortex. “This may make them more sensitive to the rewarding aspects of drinking, or more impulsive”, according to the study.
Since increased impulsivity was found in smokers, associated with decreased functional connectivity of the non-reward-related lateral orbitofrontal cortex; and increased impulsivity was found in high amount drinkers, associated with increased functional connectivity of the reward-related medial orbitofrontal cortex: “It suggested that being impulsive may be a factor leading to smoking and drinking, or vice versa,” said Cheng Wei, the lead author of the research.
The research studied brain networks and MRI results from close to 2,000 participants including smokers, drinkers, non-smokers and non-drinkers from Europe and the US.
However, the results published were obtained on populations from the general community, and do not necessarily apply to heavy smokers or drinkers, it noted.
