Though smoking and drinking behaviors are voluntary decisions they often appear inexorably linked. Researchers delving into the underlying cause for the cigarette-and-a-drink nexus found that it may be linked to stress hormones.
Lead author of the study, John Dani, a professor of neuroscience at the Baylor College of Medicine stated, “It’s pretty well understood by most people that those who smoke are more likely to drink. And these people are ten times more likely to abuse alcohol.”
Experimental trials on mice
In order to get some insight into why nicotine and alcohol are so often used, and abused, together, the researchers conducted an animal study. They gave rats some nicotine waited awhile and then gave them alcohol to drink.
The focus of the study was to study how dopamine, a chemical that helps regulate reward, pleasure and addiction seeking system in the brain, would respond to the effects of drinking after smoking.
It’s a well established fact that alcohol intake increases the amount of dopamine in the brain. Apparently, nicotine use also increases the production of the chemical. Experts theorized that the dopamine release after the combination encourages people to drink or smoke again because it brings on that feeling of being buzzed.
Contrary to expectations, the investigators found the rats’ dopamine levels after nicotine and alcohol use were really low. Assuming there was some flaw in the results, the researchers kept repeating the experiment to achieve a high dopamine level in his rats, but it never rose.
“We did that experiment so many times before we finally went, ‘Wow. This is real and now we’ve got to figure it out,’” Dani says.
Further examination of the phenomenon
To understand the mechanism, they started measuring the rats’ alcohol intake. It was noted that nicotine-addicted rats ended up drinking a lot of alcohol, a behavior quite similar to humans who smoke.
The analysis revealed that nicotine use blunts the release of dopamine that normally occurs when alcohol is consumed alone. Smokers may not feel the alcohol induced buzz as soon or as much as non-smokers, which may prompt them to drink more.
“Our findings indicate the mechanisms by which nicotine influences the neural systems associated with alcohol abuse, providing a foundation for conceptualizing strategies aimed at diminishing the link between smoking and later alcohol abuse,” says Dr. John Dani.
The study was published in Neuron.