Why are some people able to enjoy alcohol in moderation while others can’t ever seem to get enough?

A new study helps explain the physical underpinnings of alcohol enjoyment and addiction by isolating key areas in the brain that respond to alcohol consumption by producing feelings of reward and pleasure.



(Deb Lindsey/FOR THE WASHINGTON POST)

Research published Wednesday in the journal Science Translational Medicine used PET scans to capture images of activity in the brains of 25 people (13 heavy drinkers and 12 who weren’t heavy drinkers) just before and just after those people had a drink.

In all 25, drinking alcohol triggered the release of endorphins -- chemical neurotransmitters that, when they bind to certain receptors in the brain, induce feelings of pleasure. For all subjects, the more endorphins that were released in the pleasure-promoting part of the brain called the nucleus accumbens, the more pleasure the subjects reported feeling.

But for the heavy drinkers only, the more endorphins released in the brain area called the orbitofrontal cortex, which is associated with reward processing, the more intoxicated they reported feeling. That phenomenon did not occur among the non-heavy drinkers.

The findings suggest that some people’s brains are more likely than others to respond to alcohol by producing feelings of reward and pleasure, which may cause them to seek that sensation more regularly and thus crave alcohol more than people whose brains don’t work that way. That sequence could lead to their becoming problem drinkers.

The authors note that while their work builds on findings from animal studies, this is the first time science has shown exactly how alcohol’s effects on the brain make humans feel good.

The study also revealed that endorphins released in response to alcohol bind to a certain kind of opioid receptor in the brain called the Mu receptor. The authors say that discovery, along with the pinning down of which brain areas are responsible for people’s pleasurable response to alcohol, could lead to more effective drugs and other treatments for problem drinking.

Here’s a video explaining the study.