A new animal study from Johns Hopkins University has shown how drinking large amounts of alcohol can cause long-lasting damage to the brain. This damage can lead to serious problems with decision-making—even after someone stops drinking for a long time.
Researchers gave rats a lot of alcohol over the course of a month, mimicking heavy alcohol use in humans. Then they let the rats go through a long withdrawal period of nearly three months with no alcohol. After this break, the rats were tested on a tricky task that required them to make smart decisions and adjust their choices as conditions changed.
The results, published in Science Advances, were clear: rats that had been exposed to alcohol made more poor choices and had trouble learning from the changing environment. In contrast, rats that had never been exposed to alcohol did much better. They were able to quickly figure out how to get more rewards by adjusting their behavior when the situation changed.
This task was not easy—it was designed to test memory, learning, and flexible thinking. Rats had to choose between two levers. One lever gave rewards more often, but the better lever kept changing every few minutes. Rats had to stay alert and adjust their choices in order to get more treats.
The alcohol-exposed rats struggled with this challenge. They couldn’t adapt as quickly and kept making the same mistakes. This shows that heavy alcohol use may cause lasting problems in how the brain processes information and makes decisions.
Previous studies in animals hadn’t been able to show this kind of deep decision-making trouble because the tasks were too simple. This new experiment gave scientists a much clearer picture of how alcohol can cause long-term thinking and behavior problems.
When the researchers looked at the brains of the rats, they found major changes in an area called the dorsomedial striatum. This part of the brain plays a big role in making decisions and learning from experience. In the rats that had been exposed to alcohol, the brain signals in this area were much weaker and less effective.
“We now have a new model that shows what might be happening in the brains of people with alcohol addiction,” said Patricia Janak, a neuroscientist at Johns Hopkins and senior author of the study. “People with alcohol use disorder often make poor decisions, even after going through rehab. This may help explain why that happens.”
One of the most surprising findings was just how long the alcohol effects lasted. Even after three months without alcohol—much longer than a typical withdrawal period—the rats still showed brain and behavior problems.
“This may help explain why people who stop drinking still struggle with urges and bad decisions. The brain may still be affected, even if the person is sober,” Janak added.
Interestingly, these results were only seen in male rats. Female rats didn’t show the same level of long-term brain or behavior damage in this study. The researchers do not think this means females are safe from alcohol’s effects—just that the impact may be different. They plan to study this further to understand why the results varied between males and females.
The team’s next step is to look at other brain areas connected to decision-making and how they interact with the dorsomedial striatum. They also want to understand more about the gender differences they observed.
This study is important because it helps explain why people with alcohol addiction may continue to make poor decisions even after they stop drinking. It shows that the brain may still be recovering—or may never fully recover—from the effects of heavy alcohol use.
The research gives scientists a clearer idea of which brain circuits are damaged by alcohol and how that damage affects behavior. This could lead to better treatments in the future, especially those that focus on healing the brain, not just stopping the drinking.
Also, the fact that the negative effects lasted so long in animals suggests that rehab and recovery programs might need to be longer and more focused on rebuilding brain function.
In summary, this study adds strong new evidence that alcohol can cause lasting harm to parts of the brain that control learning, memory, and decision-making. It reminds us that even after someone stops drinking, the effects of alcohol can continue to impact their life—and their choices—for a long time.
If you care about alcoholism, please read studies about how alcohol affects liver health and disease progression, and even one drink a day could still harm blood pressure health.
For more health information, please see 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.
The research findings can be found in Science Advances.
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