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The dangers of alcohol-induced memory blackouts

May 19, 2023

What exactly happens when you have a blackout? Can binge drinking and blackouts harm our brains and lead to dementia?


Have you ever had a few too many drinks and experienced a blackout? Even though you were conscious the whole time, high levels of alcohol in the blood mean the brain presses “pause” on creating long-term memories. Body weight and even genetics can influence blood alcohol levels.

Alcohol affects the brain in all kinds of ways. For example, it compromises the work of the hippocampus. This brain region is important for learning and crucial for forming long-term memories. Alcohol blocks this mechanism: it attaches to special docking sites on brain cells in the hippocampus and slows down their communication.

After drinking five glasses of wine within two hours, a 23-year-old woman weighing around 60 kilograms would have a blood alcohol content of about 0.16%. This impairs brain function and causes partial blackouts, meaning some but not all memories are lost. Four more drinks down the road, at a blood alcohol level of about 0.3%, there is a 50% chance of not remembering anything at all the next day. There is no way for those lost memories to return, since they were never stored.

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High blood-alcohol levels compromise the work of the hippocampus, leading to memory lossImage: DW

The link between alcohol and dementia

Are there more serious side effects? Large amounts of alcohol are certainly not good for the brain, especially for teenagers or young adults. That’s because brains continue to mature well into our mid-20s. At that age, the brain is still optimizing its communication workflows. But the brain can't do that if it is regularly awash in alcohol. Studies have shown that binge drinking can reduce brain matter volume and quality in young adults. This in turn can affect memory and the ability to learn.

It’s not only binge drinking that can damage your brain. Consuming more than 14 drinks per week — about two alcoholic drinks per day — puts you at a higher risk of getting dementia. That’s because, over time, the alcohol destroys brain cells and brain volume can shrink. Dementia can be a devastating disease: those affected lose memories and certain cognitive skills.

Alcohol is not the only risk factor, though. Living an unhealthy lifestyle or simply ageing also increase your risk of dementia. The bottom line is: there is no healthy way to drink alcohol. The less you drink, the better.

How unhealthy is alcohol really?

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