Most of us know that excessive alcohol use can increase our risk of health issues like liver disease and heart disease. But how does heavy drinking impact the brain?
But can heavy drinking really cause dementia? To learn more about the ways alcohol can affect the brain, Everyday Health talked to Georges Naasan, MD, an associate professor of neurology at the Icahn School of Medicine at Mount Sinai in New York City. (Dr. Naasan is not one of Williams’s doctors and did not comment on her specific symptoms, diagnosis, or treatment.)
Editor’s note: This interview has been edited for length and clarity.
Everyday Health: What is currently known about alcohol use, both moderate and heavy, and how it changes the brain, specifically in terms of cognitive decline or dementia?
Georges Naasan: Alcohol can affect the brain in multiple ways. First and foremost, alcohol has direct toxicity on brain cells, causing them to die as time goes by. The cerebellum, which coordinates motor and cognitive functions, can be particularly affected, leading to difficulties in walking, tremors, and cognitive challenges.
Alcohol can also deplete a crucial vitamin called B1 or thiamine, and the scarcity of that can affect parts of the brain. The most common part that is injured is called the mammillary bodies, which is important for memory processing — people with this (injury) can have a lot of difficulty with short-term memory loss.
The thalamus, which relays information between different parts of the brain, can also be injured.
Additionally, alcohol can cause liver damage, which can lead to liver disease, increase the risk of liver cancer, and make it harder for the liver to filter out toxins from our blood and our system. Over time these toxins can build up and cause damage to the brain.
EH: Is “alcohol-induced dementia” an actual medical term or diagnosis?
GN: We don’t use the term “alcohol-induced dementia” much in clinical settings.
It’s more accurate to specify the type of dementia, such as dementia related to thiamine deficiency or cerebellar degeneration due to alcohol use.
One of the most common types of dementia that is related to alcohol use is called Wernicke-Korsakoff dementia. This involves two different brain disorders that often occur together: Wernicke’s disease, which is a kind of dementia where people do have cognitive decline and short-term memory loss, and Korsakoff’s psychosis, which is a progression that includes hallucinations or delusions.
EH: Is the impact of alcohol on the brain dose-dependent, and if so, what is the relationship between the duration and intensity of alcohol consumption and the risk of cognitive decline or dementia?
GN: The relationship between alcohol consumption and the risk of cognitive decline is likely dose-dependent. It’s likely that the longer the years and the higher the amount of alcohol consumed, the higher the risk.
However, it’s crucial to note that risk and causation are different. People may have these accumulated risks, but they may have genetic or environmental factors that have a protective effect, and they never experience cognitive decline related to alcohol use. Those same factors, along with other health conditions, may put them at greater risk.
EH: Can late-onset alcohol abuse be a symptom of dementia, and what connection did your research establish in this area?
GN: Late-onset alcohol abuse can be a presenting symptom (a symptom that makes someone decide to go to the doctor) of dementia, especially in certain types, like frontotemporal dementia. That means the brain disease is happening first, and it may be interrupting some of the reward processing machinery in the brain that could be related to impulsivity control, and that’s leading to the alcohol abuse.
In our research, we observed a higher representation of individuals with late-onset alcoholism in the group with dementia, particularly frontotemporal dementia. Some patients presented with alcoholism as the first symptom, preceding other cognitive or behavioral changes.
For doctors out there, when you see patients who have late-onset alcoholism, which is defined as happening after the age of 40 or older, perhaps these people need a little more attention and an evaluation for a neurologic disorder. We’re not saying that this is happening for everyone who develops this, but it is possible that the drinking is the result of a medical condition that they don’t really have any control over. We identified a number of cases where that was the case.
EH: What are some of the ways frontotemporal dementia can appear?
GN: There are multiple brain conditions that fall under this umbrella term, so there are different ways it can manifest.
In the behavioral variant of frontotemporal dementia, people have changes in personality, usually in at least three out of six domains.
- Disinhibition, where the person loses the ability to understand social situations and social norms. They “have no filter,” to put it in lay terms.
- Becomes apathetic or loses motivation and doesn’t want to do things or be engaged in activity
- Loses empathy and sometimes becomes quite self-centered
- Develops obsessive or compulsive disorder, so they may start doing the same thing over and over, saying the same thing over and over, or develops rituals they never had before
- They may become hyper-oral, which can take the form of eating a lot, drinking a lot, or smoking a lot — anything that has to do with ingesting things or putting things in their mouth.
- Executive function difficulties, meaning they begin to lose the ability to make decisions and pass judgment on a situation
EH: When heavy alcohol use coexists with dementia, can it be challenging to differentiate between symptoms of cognitive decline and intoxication?
GN: Yes, in some cases it may be challenging to differentiate between cognitive decline and intoxication when heavy alcohol use is involved. I don’t know that I’ve read any scientific papers on this, so this comes from my own experience and experiences that I’ve heard about from my colleagues.
Family or friends may have certain thoughts or convictions about what is going on and why it’s going on. Initially, individuals might be mistaken for being inebriated, which could lead to delays in seeking medical care. The overlap of symptoms makes it crucial for clinicians to carefully evaluate and consider the possibility of an underlying neurologic disorder in these situations.
EH: Is it possible to reverse any brain damage caused by alcohol by abstaining from drinking or addressing deficiencies like thiamine?
GN: The possibility of reversing alcohol-induced brain damage depends on whether the damage is permanent. Did brain cells die or are they dysfunctional because they didn’t have the vitamin that they need but they’re still alive?
Although there are cases where the damage is permanent, abstaining from alcohol and adopting a healthy lifestyle may prevent further injury and potentially help build new connections, improving symptoms. However, in degenerative diseases, regaining lost functions is challenging, as these diseases involve ongoing cell death.
EH: Is there a safe level of alcohol consumption that does not pose an additional risk to brain health?
Importantly, it’s not cumulative. So skipping five days of drinks doesn’t mean you can safely have five drinks in one 24-hour period — it’s still only one. Moderation is key to minimizing potential risks to brain health.
The Takeaway
Long-term alcohol abuse can damage the brain in multiple ways: Alcohol can kill brain cells, lead to vitamin deficiencies that impair brain function, and prevent the liver from filtering out toxins that can then accumulate in the brain. Late-onset alcohol abuse (after age 40) can be a symptom of dementia rather than a cause. Other serious changes in personality — like no longer having a verbal “filter” in social situations, extreme apathy, becoming excessively self-centered, or suddenly overindulging in food or smoking — can also be symptoms of dementia. Always keep an eye on sudden behavioral changes in yourself or others, as these could signal deeper health issues.
