For the first time, scientists have shown how heavy drinking can cause lasting brain damage that affects decision-making, even long after someone stops drinking.
In a new study using rats, researchers found that alcohol changes how the brain works, leading to long-term problems in making good choices.
The research, led by a team at Johns Hopkins University, was published in the journal Science Advances. The team exposed rats to large amounts of alcohol for one month. Then, the rats went through almost three months of sobriety. After this withdrawal period, the rats were given a tough test that involved choosing between two levers to get a reward.
One lever gave more rewards than the other, but the better choice kept changing every few minutes. To get the most rewards, the rats had to quickly figure out which lever was best and change their behavior often.
Rats that had not been exposed to alcohol performed well. They learned to adjust and made better decisions. But the rats that had drunk a lot of alcohol performed worse. They had trouble keeping up when the better lever changed. They struggled to switch strategies, showing poor decision-making.
This task was more difficult than the ones used in past studies. Earlier experiments didn’t show major decision-making problems in animals with alcohol exposure because the tests were too easy. This time, the harder task revealed important differences.
“Our experiment was quite challenging and the alcohol-exposed rats just couldn’t do it as well,” said Dr. Patricia Janak, a neuroscientist at Johns Hopkins. “The control rats made better choices faster, and their brain activity was stronger in areas linked to decision-making.”
The researchers found that the key brain region affected was the dorsomedial striatum, an area responsible for decision-making. In the alcohol-exposed rats, this brain region was not working properly. The neural circuits had been damaged, making it harder for the brain to process information.
One surprising result was how long these effects lasted. Even after nearly three months of sobriety, the alcohol-exposed rats still showed problems with thinking and brain function.
This could explain why so many people who struggle with alcohol addiction relapse after treatment. Even when they’ve stopped drinking, the brain may still have damage that affects their choices.
Interestingly, the researchers only saw these problems in male rats. Female rats did not show the same behavior or brain changes, but the scientists don’t believe this means females are safe from alcohol’s effects. There may be differences in how alcohol affects the brains of males and females, which the team plans to study next.
The researchers hope to keep exploring how alcohol affects other parts of the brain connected to decision-making and what causes the sex differences. Understanding how long-term alcohol use changes the brain could help develop better treatments for alcohol addiction.
Other authors of the study include Yifeng Cheng, Robin Magnard, Angela J. Langdon of the NIH, and Daeyeol Lee of Johns Hopkins.
If you care about alcoholism, please read studies that your age may decide whether alcohol is good or bad for you, and people over 40 need to prevent dangerous alcohol/drug interactions.
For more information about alcohol, please see recent studies about moderate alcohol drinking linked to high blood pressure, and results showing this drug combo shows promise for treating alcoholism.
The study is published in Science Advances.
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