Scientists have discovered new evidence showing how heavy alcohol use can cause long-term damage to the brain and behavior.
For the first time, researchers have shown in animals that drinking a lot of alcohol over time can lead to lasting problems with decision-making.
These problems continue even after the alcohol is gone from the body for several months. This new study helps explain why people who struggle with alcohol addiction often have trouble making good decisions, even after they stop drinking.
The study was done by scientists at Johns Hopkins University and published in the journal Science Advances. They focused on rats to understand how alcohol affects the brain. Rats are often used in brain research because their brains work in similar ways to human brains.
The researchers gave rats very high levels of alcohol for one month. Then, the rats went through a withdrawal period where they had no alcohol for nearly three months. After that, the scientists tested how well the rats could make decisions.
The test was designed to be challenging. The rats had to choose between two levers to get a treat. One lever gave a reward more often than the other. Every few minutes, the lever with the better reward would change. This meant the rats had to constantly pay attention, remember what worked before, and adjust their choices.
Healthy rats usually do well on this kind of test. But the rats that had been exposed to alcohol struggled. They didn’t adapt as quickly and didn’t make smart choices to get the reward. Their performance was clearly worse than that of the rats who had not received alcohol.
This poor performance is similar to what researchers see in humans with alcohol use disorder. People with this condition often have trouble learning from mistakes and making smart decisions, especially when things change quickly.
Earlier animal studies didn’t show this kind of thinking problem because the tests were too easy. This time, the task was hard enough to reveal the real impact of alcohol on thinking.
When the scientists looked inside the rats’ brains, they found that the area called the dorsomedial striatum had changed. This part of the brain plays a big role in decision-making. In the alcohol-exposed rats, this region was not working properly.
The brain signals related to decision-making were weaker. This suggests that alcohol damaged the brain circuits that help process information and make good decisions.
One surprising result was how long the effects lasted. Even after three months without alcohol, the rats still had brain problems. This could explain why it’s so easy for people to relapse after going through rehab. The brain might still be struggling to work correctly, making it harder to resist the urge to drink again.
Interestingly, the researchers only saw these brain and behavior problems in male rats. Female rats didn’t show the same issues. That doesn’t mean alcohol is safe for females—it may just affect them differently.
The scientists believe that male and female brains might react in different ways to long-term alcohol exposure, and they plan to study this more in the future.
This study gives us a clearer picture of how alcohol changes the brain. It shows that heavy drinking can damage the parts of the brain that help us think and make choices. These effects can last long after someone stops drinking. Understanding this could help doctors find better ways to treat alcohol addiction and prevent relapse.
The study is published in Science Advances.
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