By Madeline Holcombe, CNN
(CNN) — Researchers came to Dr. Chris Knowles’ school in England when he was 18 years old to run an experiment. They wanted to see which novice drinkers responded the most to alcohol and who would later go on to develop a drinking problem.
They placed two double vodkas in front of each student to measure their reaction, he recalled. Knowles downed his and then reached over and drank the two belonging to a girl next to him, who didn’t care much for liquor.
Knowles, now a professor of surgery at Queen Mary University of London and author of a new book on the science of excessive drinking, said he later went on to seek treatment for alcohol use disorder.
Research has shown no amount of alcohol is good for the heart or brain. Despite those findings, and often personal consequences for some drinkers, excessive alcohol use is fairly common, with 17% of adults in the United States reporting binge drinking, according to the US Centers for Disease Control and Prevention.
Describing his time drinking as 10 years of fun, then 10 years of fun with negative consequences and another 10 years of only negative consequences, Knowles has investigated alcohol’s appeal in his new book, “Why We Drink Too Much: The Impact of Alcohol on Our Bodies and Culture.”
The short answer to why humans drink? “Because it’s fun and because we learn that good things happen when we do it, or at least we think good things have happened when we did it,” Knowles said.
The long answer offers insight into why some people struggle more than others and why they keep drinking, even when it becomes clear good things aren’t happening.
Wired for alcohol
When he thinks back to friends from his early drinking days, plenty of them drank less than he did –– but he also knew some who drank a great deal more than he did and didn’t develop any problems, he said.
The same might be true of your friend group. There isn’t always a direct correlation between those who drink the most and those who will have a problem, Knowles said.
How much someone drinks and the relationship a person has with alcohol comes down to many factors, including environment, biology and psychology, he said.
Alcohol stimulates some of the same pleasure centers of the brain as those that give a feeling of reward when you seek out necessities such as food and relationships, Knowles said.
But alcohol also works on the negative side, too.
“The more you drink, the more you drive those stress neurotransmitters, and so you’re miserable when you’re not drinking,” said Dr. George Koob, director of the National Institute on Alcohol Abuse and Alcoholism.
“You’re really digging that hole, and you’re drinking to fill the hole. But unfortunately, every time you try to fill the hole by drinking, you’re making the hole deeper.”
When talking about biological factors behind excessive use of alcohol, it is easy to assume that some people are just physiologically wired to take a drink and have their brain say, “More, now” –– like young Knowles with vodka. And there is truth to such thinking because some people’s physiology will just agree more with alcohol, said Dr. Danielle Dick, director of the Rutgers Addiction Research Center and a professor of psychiatry at the Rutgers Robert Wood Johnson Medical School.
But that physiological factor isn’t the whole story, she added.
A major part of the biology behind who develops problematic use of alcohol has to do with how an individual’s brain is wired to pr