Medically Reviewed by Annamarie Coy, BA, ICPR, MATS
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Although it's common to think alcohol can kill brain cells, it doesn't. However, that doesn't mean there's no effect on your brain. Alcohol is a neurotoxin that damages cognitive function in multiple ways.
Research indicates heavy drinking can damage neurons by altering the structure, development, and function of dendrites. Dendrites are responsible for problem-solving, memory, and focus. They are essential for the communication between neurons.15
Alcohol use also leads to loss of brain volume, causing brain shrinkage. This doesn't just apply to heavy drinking. Some studies suggest this is also true for moderate alcohol consumption.2
Researchers point to thiamine (vitamin B1) deficiency as the culprit. Thiamine is an essential vitamin for the metabolism of dendrites.
Alcohol inhibits the absorption of thiamine. Because of this, people who struggle with alcohol use disorders (AUDs) end up malnourished, leading to thiamine deficiency.
According to the National Institute on Alcohol Abuse and Alcoholism (NIAAA), heavy drinking for men is having four or more drinks per day or more than fourteen drinks per week. For women, this is three or more drinks daily or more than seven in a week.
A recent British study showed moderate drinkers tripled their risk of brain damage over 30 years. Specifically, moderate drinking is associated with a reduction in brain volume. According to the study, moderate drinkers had a three times greater risk of brain shrinkage over 30 years.12
Heavy drinkers had six times the risk, showing that more drinking leads to more damage.12 However, this shrinkage does not appear to be due to brain cell death but from other damage.
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When a person drinks alcohol, several brain areas are affected. This causes short and long-term emotional and behavioral changes. One area of the brain alcohol affects is the cerebral cortex, which is responsible for thinking and decision-making.
Here are the short- and long-term side effects of alcohol on your brain:
The short-term side effects of alcohol on your brain include:
This happens because alcohol affects the limbic system and the cerebellum, which controls emotions and coordination respectively. Alcohol can also affect the hypothalamus. This interferes with hormones and can cause excessive urination and sexual impairment.
Once alcohol reaches the medulla, it can affect most basic bodily functions such as consciousness, breathing, and heart rate. Because of this, drinking may cause the person to feel sleepy and slow down their heart and breathing.
Some long-term effects of alcohol on the brain include:
Long-term alcohol use causes persistent memory impairment. This affects short-term memories or "working memory." Because of this, short-term memories never get stored as new long-term memories.
Studies show that alcohol use causes parts of the brain to shrink or become less dense.15 This is called brain atrophy.
The frontal lobes are important for voluntary movement, language, and higher-level thinking. One study showed shrinkage of 11% in this area in heavy drinkers.15
Shrinkage of the cerebellum, which controls balance and movement, can happen in long-term drinkers. This is also true of the corpus callosum, an area that links the right and left sides of the brain, allowing communication between them.2
Another vulnerable area is the hippocampus, which is vital for learning and memory. Atrophy in this area is also strongly linked to Alzheimer's Disease.1
Neurogenesis is the creation of new brain cells. It is now known that the body can generate new brain cells (neurons).
Scientists also know alcohol interferes with this process, which some think may explain brain atrophy.6 However, it has been shown that neurogenesis does begin again if a person stops drinking, though it takes months for the new neurons to be put in place.2
Wernicke syndrome and Korsakoff syndrome are two disorders that often occur one after the other. It is a devastating brain disorder associated with a lack of thiamine. This happens because heavy drinkers eat poorly and are often malnourished.
Wernicke syndrome develops first and has the following symptoms:
Without medical intervention, 80% of affected people develop Korsakoff syndrome. In this phase, the person shows significant short-term memory impairment, unable to create new memories and retain new information. Sometimes long-term memories are lost as well.
The ability to pay attention and have a conversation is not affected, so you may seem normal to a casual observer. You may not even be aware of the problem. WKS may cause permanent nerve damage and weakness in the arms and legs.
Many heavy drinkers find quitting difficult, even if they want to. This is due to alcohol dependence or withdrawal. If you stop drinking, you may experience uncomfortable withdrawal symptoms ranging from mild to severe.
Withdrawal symptoms include:
If you have an alcohol use disorder (AUD) and a mental health problem, it is essential to seek help for both conditions.
Research indicates alcohol exposure over a significant period of time will lower IQ. A study of just under 50,000 Swedish military conscripts between 1969 and 1970 found that IQ was inversely correlated with heavy alcohol consumption.11 A study in neighboring Norway found similar results.9
Women who drink while pregnant put their children at higher risk of developing fetal alcohol spectrum disorder (FASD). Children born with Fetal Alcohol Syndrome (FAS) have IQs well below average.9
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Research has shown that the brain damage caused by alcohol can be at least partially reversed. According to MRI studies, the brain recovers to some extent after a significant period of abstinence from 1 month to a year.2 Brain scans have also shown that some brain atrophy can be reversed.
Some improvement has been seen in just one month of abstinence, with mild improvements after 6 months. The degree of recovery depends on the duration and quantity of alcohol use, though most published studies indicate complete recovery is rare.13
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The level of alcohol-related brain damage depends on factors such as the:
Generally, it can take months for your brain to generate new cells. The reversal of brain volume loss was seen as soon as a month after the drinking stopped. Some mental faculties also begin to improve after 6 months.
However, this process is uneven, and full recovery is unlikely. One study showed no regrowth at all of the prefrontal lobes after 6 months.13
Symptoms of alcohol use disorder include:
If you or someone you know is showing symptoms of AUD, consider reaching out to a healthcare professional. Although there is no cure for AUD, there are treatment programs that can help.
Available treatment options include:
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