A recent study from the University of Massachusetts Amherst suggests that using alcohol to cope with stress in early adulthood can have lasting effects on the brain that may persist even after years of sobriety. The study found that these changes begin to surface by midlife, making people less mentally flexible and more likely to return to alcohol during stressful times, and contributing to the pattern of cognitive decline associated with dementia and Alzheimer’s disease.
Published in a magazine Alcohol clinical and experimental researchthe findings shed new light on how alcohol and stress work together to reshape brain circuits. Researchers say this improved understanding could ultimately lead to better treatments that address the long-term effects of alcohol use, rather than focusing solely on abstinence.
How stress and alcohol strengthen their interaction
Scientists have long known that stress and alcohol can stimulate each other. Alcohol may temporarily relieve feelings of stress, but repeated drinking can weaken the brain’s natural ability to naturally manage stress. Over time, you may find yourself relying on alcohol more often and in larger amounts to get the same sense of relief.
At the same time, heavy drinking can contribute to bad decisions and their consequences, increasing stress. This creates a cycle that becomes increasingly difficult to break as the brain adapts to repeated exposure to both stress and alcohol. The researchers wanted to understand what these changes look like over time.
“My lab studies the neural circuits that underlie how we make decisions,” said Elena Vazei, associate professor of biology at the University of Massachusetts Amherst and senior author of the study. “We all know that drinking can often lead to poor decision-making, but we wondered how the combination of drinking in adulthood and stress might affect that circuitry, especially as we get older. If we can understand how alcohol and stress change the brain’s circuitry, it could help us find the best ways to help people.”
Stress and alcohol combined cause greater brain changes
With support from the National Institute on Alcohol Abuse and Alcoholism (NIAAA), Vasey and her team studied mice. This is because many mouse brain circuits are very similar to human circuits. Their results showed that the combination of alcohol and stress had a much greater impact than either factor alone.
The researchers found that consuming large amounts of alcohol as a way to cope with stress in early adulthood made animals more likely to return to drinking when stressed in midlife, even after long periods of complete abstinence. This suggests that alcohol and stress together can cause permanent changes in the brain that persist far beyond the period of drinking.
Interestingly, the researchers found little difference in learning ability between middle-aged mice with a history of stress drinking and mice with mild drinking habits. The biggest difference was cognitive flexibility, the ability to quickly adapt to changing circumstances and make new decisions when conditions change.
“Midlife is when problems start to pile up,” Vasey says. “We know that alcohol is a risk factor for early cognitive decline, and we’ve seen that this combination of alcohol and stress causes a kind of difficulty in adapting to changing circumstances, which also occurs in the early stages of dementia.”
Permanent damage in critical decision-making centers
To understand why these long-term effects occur, the researchers focused on a small region of the brainstem called the locus coeruleus (LC), which plays a key role in adaptive decision-making in both mice and humans.
In a healthy brain, LC is activated in stressful situations and returns to normal when the stress passes. However, in mice exposed to both alcohol and chronic stress, the LC lost a key molecular mechanism that normally allows it to shut down its activity. As a result, brain regions remained confused and were less able to guide effective decision-making.
The research team also found high levels of oxidative stress within the LC. This form of cell damage is common in the brains of Alzheimer’s patients and can damage cells throughout the body. Even after long periods of abstinence, the middle-aged brains of mice that had previously been heavy drinkers showed little sign of repairing this damage.
“The brain can have a really hard time recovering from chronic stress and a history of drinking in early adulthood,” Vasey says. “We believe that oxidative damage may be one of the reasons why heavy drinking persists, leading to a return to alcohol even after long periods of abstinence. These persistent changes in the brain impair decision-making and may lead to early cognitive decline of the kind associated with dementia and Alzheimer’s disease. It also leads to: The brain’s wiring system is damaged, so quitting drinking or making better decisions is not a matter of willpower; after a history of stress and drinking, the brain simply functions.”Our treatment strategies must be able to address these long-term differences. ”
