Scientists have discovered differences in the brain that seem to explain why some people drink more than others and why some become addicted to alcohol.

The brains of heavy drinkers are more receptive to the endorphins that produce pleasure.

Researchers at the University of California, San Francisco, discovered that the brains of people who drink to excess seems to be particularly receptive to the compounds that cause the sensation of pleasure and reward after a drink.

Although it was suspected for decades, is the first time that a study could observe in the human brain.

And the discovery, the scientists report in the journal Science Translational Medicine (Science, Translational Medicine), could lead to new tools to treat alcohol abuse.

We know that alcoholism is a disorder caused by both biological and psychological factors.

Past studies conducted on animals have shown that alcohol abuse causes changes in brain chemicals that increase tolerance and, therefore, the dependence on the substance.

So far, however, has not managed to understand what the biological mechanisms involved in these changes in brain structure and make that an individual has a compulsive need to continue drinking.

More endorphins, more pleasure

Like other addictive substances like cocaine and amphetamines, alcohol causes the release of endorphins, chemical compounds that attach to opioid receptors in the reward centers of the brain causing the sensation of pleasure produced by alcohol.

What has until now ignored, however, the mechanisms underlying this process of consumption and reward, and why some people feel the need to keep drinking and not others.

To investigate, Dr. Jennifer Mitchell and his team subjected a group of 25 individuals and 12 -13 heavy drinkers to nondrinkers brain scans, PET scans (positron emission tomography).

"This is something we have speculated for nearly 30 years, based on animal studies, but until now had not been seen in humans. And we offer the first direct evidence of how alcohol makes people feel good" said Dr. Jennifer Mitchell

The images were taken before and after both groups of subjects consumed an alcoholic beverage.

The results showed that alcohol consumption caused both drinkers and nondrinkers in the release of endorphins in two particular regions of the brain: the nucleus accumbens and orbitofrontal cortex.

This reveals, the authors say that regardless of how much a person drinks, alcohol causes the release of endorphins in these two brain regions.

They found that the more endorphins are released into the nucleus accumbens, the greater the feeling of pleasure of the individual, both drinking and non-drinker.

However, the more endorphins are released in the orbitofrontal cortex, the greater the feeling of intoxication experienced by heavy drinkers.

But this was not experienced by non-drinkers.

According to scientists, this shows how endorphins contribute to long-term alcohol abuse and how the release of large amounts of endorphins causes the alcoholic beverage more enjoyable.

Which in turn contributes to want to drink more.

As Dr. Mitchell explained, "this indicates that the brains of heavy drinkers or problem drinkers are changing in a way that alcohol makes finding increasingly more pleasant."

"And this may be the key to how it develops, first, the problem of alcohol."

"For this feeling increasingly large rewards to drink more and more," he adds.

The researcher says: "This is something we have speculated for nearly 30 years, based on animal studies, but until now we could not observe in humans."

"And we offer the first direct evidence of how alcohol makes people feel good."

The research was funded by the Department of Defense United States and the Fund for Research on Alcohol and Drug Abuse of the State of California. Presented by Multiple News