Three young men holding up pints of beer cheering each other - by Doug Cook RD

Alcohol Effects On The Brain. What Are They?

Beer pints - Alcohol Effects On The Brain. What Are They?


Working at Canada’s largest teaching hospital for mental health and addiction, I see the negative impact of alcohol consumption on health every day.


I see it in the geriatric patient population that I follow where, on any given day, many who are admitted are facing alcohol-related neurocognitive disorder, a.k.a. alcohol induced dementia.


Of course, I see it in the medical detox unit as well, where people are admitted for the supervised medical management of alcohol withdrawal. This is necessary to avoid the severe complications, including possible death, from attempting any kind of alcohol detox at home.


This isn’t about being a downer on alcohol. I imbibe it myself on occasion but rather a review of the effects of alcohol on the brain, mood and long term cognitive health. And, as readers of this blog know, the health of the brain influences the health of the gut, both of which are affected directly and indirectly by alcohol consumption.

Alcohol consumption

Alcohol is the most widely consumed drug worldwide.


How much, and how often, an individual drinks, increases or decreases the impact of alcohol on the body. Abstinence prevents the direct impact of all alcohol-related effects on an individual. Some negative health impacts are temporary and can be reversed or reduced once a person stops drinking or drinks within recommended safer guidelines (1, 2).

Canada and the world

Alcohol is a widely, socially acceptable part of life for most Canadians. An estimated 80% of us drink. Similar patterns are seen around the world (3).


Of course these numbers are tricky. It’s based on surveys where people self-report their consumption. It’s hard-wired into our primate brains to under-report so-called “unhealthy” things and over-report the “good” stuff. We all do it, so don’t feel bad.


Estimating the consumption of beer is easier; it comes in a standardized serving size (a 341 ml or 12 oz bottle or can). But when it comes to wine, fortified wine, and spirits which tend to be “free poured”, people routinely and predictably under-estimate just how much they drink. Did you know a 750 ml bottle of wine has 5.2 standard servings? 🙂


  • Canadians reported drinking 8.2 litres of pure alcohol per year.
  • 23% of drinkers drink heavily.

United States

  • Americans reported drinking 8.7 litres of pure alcohol per year.
  • 24.5% of drinkers drink heavily.

United Kingdom

  • People from the UK reported drinking 10.4 litres of pure alcohol per year.
  • 33.4% of drinkers drink heavily.


  • Australians reported drinking 10.4 litres of pure alcohol per year.
  • 13% of drinkers drink heavily.

Canada’s low-risk alcohol drinking guidelines

To reduce risks of short-term injury and harm:

  • Women should have no more than 3 standard drinks on any single occasion.
  • Men should have no more than 4 standard drinks on any single occasion.

To reduce long-term health risks:

  • Women should have no more than 10 standard drinks a week, with no more than 2 drinks a day on most days.
  • Men should have no more than 15 standard drinks a week, with no more than 3 drinks a day on most days.


Standard drink infographic - Alcohol Effects On The Brain. What Are They?

Infographic credit

Chronic consumption volume definitions

  • Light: less than 1, to 1 standard drink per day
  • Moderate: 1 to 2 standard drinks per day
  • High: 2 to 3 standard drinks per day
  • Heavy: 4 or more standard drinks per day

Binge drinking*

  • Men: 5 or more standard drinks on the same occasion
  • Women: 4 or more standard drinks on the same occasion
  • Heavy alcohol use: binge drinking on 5 or more days in the past month


People tend to get defensive about the term “binge drinking” like it’s a judgment. Or they’re quick to defend that they can drink that volume and still function or not be “messy”. From a physiological impact perspective, alcohol consumption volume considers the effect at a cellular/metabolic level. The fact that a person can “hold their liquor” is irrelevant.


The impact of binge drinking (or heavy episodic drinking) on long-term health is a complex and evolving story. Evidence suggests that binge drinking is linked to negative impacts on the liver, the brain, cancer and cardiovascular health. In some cases, the impacts of binge drinking are no different than drinking the same amount over a longer period.


*National Institute on Alcohol Abuse and Alcoholism

Effects of alcohol on your body


One of the most important motivations for drinking is because it is pleasurable. This is referred to as the hedonic principles of food (including beverages). This is what makes eating and drinking enjoyable. This effect is governed by neurotransmitters. Alcohol interacts with several of them including gamma-aminobutyric acid (GABA), glutamate, norepinepherine, serotonin and dopamine (4).


In very simple terms:

  • Serotonin – is the “feel good” chemical that increases a sense of happiness and well-being and helps to regulate anxiety
  • GABA – helps to calm the nervous system, in this sense it inhibits its activity and brings a sense of calm
  • Dopamine – responsible for focus and attention and creates pleasant feelings, and has a reinforcing effect on the brain’s reward center.
  • Glutamate – is a stimulating neurotransmitter (called “excitatory”) and is by far the most abundant in nervous system
  • Norepinepherine – a neurotransmitter responsible, in part, for arousal, heightens senses, and is the “fight or flight” neurotransmitter

Normally, excitatory (stimulating) and inhibitory (calming) neurotransmitters work together in a ying and yang fashion to allow just enough stimulation and inhibition. Our emotions ebb and flow appropriately. Balance is largely maintained within a healthy range.


For ease of concept, when we drink, we experience a combination of feelings. We have a sense of almost immediate calm & relaxation, while at the same time, a sense of pleasure. We feel calm and relaxed because alcohol increases the calming effects of GABA  and decreases glutamate’s stimulating effects. Alcohol also increases the release of serotonin and dopamine resulting in a sense of enjoyment (5, 6).


Alcohol also affects opioid receptors in the brain which leads to the release of beta-endorphins. These are the same endorphins responsible for the turn of phrase “runner’s high” because they are also released during exercise.

Is alcohol a stimulant?

Conventional wisdom says no. But many experts say otherwise. Stimulants typically target dopamine and norepinepherine (a neurotransmitter that can raise heart rate and breathing), Depressants on the other hand target GABA.


Given that alcohol stimulates the release of dopamine, alcohol does have some stimulatory effects. Initially alcohol acts as a stimulant; many report feelings of elation, excitement and extroversion (in part of course, to decreased inhibitions). Given dopamine and norepinepherine’s role in increasing energy levels and arousal, alcohol initially helps to also decrease fatigue.  (5, 6, 7).

Is alcohol a depressant?

Alcohol is also a depressant. Unlike most drugs that are one or the other, alcohol is different. These two seemingly opposite effects, stimulant and depressant, are central to understanding how alcohol affects the brain. (5). With continued consumption, alcohol’s effect on depressing glutamate’s excitatory role leads to sedation and drowsiness.


Alcohol has a classic biphasic (2 phases or parts) effect. Everyone who drinks knows that some alcohol makes them feel good for the reasons stated above. And, human nature as it is, we assume that if a little feels good, more will feel better. Given alcohol’s dual effect of both exciting and inhibiting the nervous system, and its impact on opposing neurotransmitters, greater consumption makes people feel worse.


Wine. Red - Alcohol Effects On The Brain. What Are They?


How long does alcohol stay in your system?

It takes about one hour for a healthy liver to process and eliminate eight to 10 grams of alcohol, or about two-thirds of the alcohol contained in a standard drink (a standard drink has 13.6 grams of alcohol). This rate is constant, no matter how much alcohol has been consumed or what food or other non-alcoholic beverages are drank. This is why alcohol poisoning can occur. You can always out-drink your livers’ ability to detoxify it.


Drinking heavily usually results in a “hangover,” beginning 8 to 12 hours after the last drink. A hangover is caused in part by acetaldehyde, a toxic chemical that is created as alcohol is processed by your liver. Other causes include dehydration and changes in hormone levels. Symptoms can include:

  • Headache
  • Nausea
  • Diarrhea
  • Shakiness
  • Vomiting

Alcohol and the brain

Alcohol is a psychoactive drug which acts on the brain leading to changes in thinking, mood, consciousness and behaviour. Of course, the effects of alcohol are dose-dependent and differ from person to person. Other considerations are any activities a person is doing while they’re drinking, as well as, their underlying state of health.


Can alcohol kill brain cells? Yes, but it’s not something to become overly alarmed about. How much and how often a person drinks will influence how “neuro toxic” a given consumption pattern will have on long term brain health.


Of course, there are no recommendations for people to start drinking or that they should drink for any kind of benefit. There’s no such thing as zero risk with alcohol consumption. Guidelines for safer alcohol consumption are about reducing any possible negative impact that alcohol may have on health.


A healthy response to stress is essential for good health however, stress is always used in a negative way. “Stress” is neither good nor bad. Stress just prepares all organisms, including us, to meet any physical or psychological demands placed upon it. When it comes to alcohol and stress though, it’s kind of a natural fit.


Why? Given how alcohol can increase a sense of calm and sedation while increasing a sense of pleasure, alcohol is often used as a way to cope when life makes us want to pull our hair out. But, not surprisingly, drinking alcohol can negatively affect how your body, and it’s neurotransmitters and hormones, reacts to stress including its impact on cortisol (8). It goes back to the biphasic effect of alcohol, a small can relieve stress, but it doesn’t take much to interfere with the normal stress cycle.


Also, stress and other emotions such as anxiety and depression often go hand-in-hand. While alcohol can initially relieve stress and anxiety, due to alcohol’s impact on neurotransmitters in the brain, stress can feel worse after alcohol wears off (9, 10, 11, 12, 13).


There is an association between alcohol and overall stroke risk. This is because alcohol contributes to medical conditions that increase the risk for strokes such as high blood pressure, diabetes, being overweight, liver damage and by triggering atrial fibrillation.


Specifically, alcohol can increase the risk for hemorrhagic stroke; a stroke caused by the rupturing of a blood vessel in the brain because alcohol reduces the protein needed for blood clotting (14, 15). On the flip side, because alcohol can decrease clotting, moderate alcohol consumption decreases the risk for the most common type of stroke; ischemic. This kind of stroke results from clots which block the blood vessels in the brain.


The question of the day is; does the increased risk for a hemorrhagic stroke and increased intracerebral bleeding out weigh the benefits of reducing an ischemic stroke? The good news is, there are other ways to reduce ischemic stroke (cardiovascular disease) that doesn’t rely on alcohol.


Whisky being poured - Alcohol Effects On The Brain. What Are They?


Mood disorders

Depression: alcohol and depression are definitely related. Signs of depression include sadness, loss of interest in activities, guilt, and feelings of worthlessness. Many people drink alcohol to help them cope with their depression. Alcohol’s sedative effects appeal to people as a way to be distracted from their persistent feelings of sadness (16).


Can alcohol cause depression? It’s likely not a linear relationship. People who are depressed may use alcohol to cope but alcohol can also cause/aggravate depression. Problematic drinking can lead to feelings of guilt, isolation, and ultimately depression, especially if an underlying cause for drinking hasn’t been identified (17).


Interestingly, inflammation is a risk factor for, and aggravates depression independently (18, 19, 20). Alcohol can increase inflammation throughout the body, as well as, the brain which is associated with depression (21). Alcohol can also increase the movement of bacteria and bacterial toxins from the gut into the the general circulation increasing inflammation causing damage to the tissues throughout the body (22).


Bipolar disorder: bipolar disorder (manic depression) and alcohol use disorder commonly co-occur or are “concurrent”. About 45% of those with bipolar disorder also have alcohol use disorder per the DSM-V classification. The link between other mental health issues (schizophrenia etc.) and problematic drinking is less clear. Alcohol use can worsen the course of someone with undiagnosed bipolar disorder making it harder to diagnose and treat (23).


During periods of hypomania or a manic episode, controlling the amount of alcohol consumed could be extremely difficult.  Also, a hypomanic/manic state can be compounded because alcohol lowers inhibition; together, impulsivity may worsen.  Alcohol can also increase the sedative effects of any mood stabilizers used to  treat bipolar which is dangerous. Abstinence maybe be the best course to take.


Alcohol and anxiety often go hand-in-hand because people routinely drink specifically to relax and reduce feelings of uneasiness. It’s often used in social situations as well for this reason; alcohol helps to “take the edge”.


Those with social anxiety disorder are most susceptible. About 20% have some form of alcohol use disorder or dependence (24). It’s true, alcohol can reduce feelings of anxiety temporarily given its sedative properties, but it’s not a sustainable strategy in the long run.


Can alcohol cause anxiety? Somewhat yes. Habitual alcohol use can actually increase anxiety within a few hours of consumption; this can last into the next day(s). Also depending on how much is consumed and for how long, alcohol can rewire the brain making an individual more susceptible to the development of anxiety problems. Neurotransmitter metabolism and neuron function can be altered increasing the risk for anxiety.


Martini - Alcohol Effects On The Brain. What Are They?



Knowing what factors increase the risk of dementia is an important first step to lowering your risk. The usual suspects include advancing age, diabetes, smoking, elevated homocysteine (a.k.a. inflammation), genetics, atherosclerosis, high blood pressure, long term use of benzodiazepines and alcohol use (25, 26, 27, 28, 29, 30, 31).


Alcohol induced dementia isn’t widely appreciated by most people. When asked what the main concern with alcohol consumption is, most will answer the impact on liver health and/or cirrhosis.


The fact of the matter is, the alcohol dementia link has been understood for decades. Most of us “get” that alcohol can damage brain cells, but the connection to cognitive decline as a consequence of concern? Not so much.


Damage may be the result of the direct effects of alcohol on brain tissue (inflammation and oxidation) or indirectly by causing poor health including nutrient deficiencies. Alcohol is directly toxic  because of acetylaldehyde, a product of alcohol breakdown/metabolism (32, 33, 34, 35, 36, 37).


While any of the 25 or so vitamins and minerals are at risk of deficiency with alcohol use (depending amount consumed and for how long); the nutrients that are most susceptible are the B vitamins, especially vitamin B1 or thiamine (38, 39, 40). This can increase the risk for Wernicke-Korsakoff encephalopathy a.k.a. alcohol induced dementia.


Alcohol and medications

You’re probably familiar with the drug interaction warning labels that appear on prescription bottles if you’ve ever used them. Drugs can interact with each other, often in dangerous ways, Well it’s no different with alcohol. It can have interactions with many psychiatric and mental health-related medications, as well as, a popular OTC sleep aid.


Xanax: or Alprazolam, is one of the more common benzodiazepine medications (“benzos”) prescribed for panic disorder, generalized anxiety disorder (GAD), and social anxiety. Benzos are involved in about 1/3 of all prescription drug overdoses, typically combined with painkillers (41).


Xanax and alcohol isn’t a good mix because both have sedating effects. Taking Xanax with alcohol will intensify the effects of alcohol, which can cause increased drowsiness, dizziness, muscle weakness, confusion, coma, and death.


Adderall: is a central nervous system stimulant (increases dopamine) primarily used for the treatment of ADHD. It is also used to treat severe narcolepsy. Adderall and alcohol can be dangerous because when taken together, their respective effects feel lessened (42). If a person perceives each isn’t working effectively, it can be easier to overdose. Adderall can give the impression that a person can drink more by masking the effects of the alcohol; they’ll feel less drunk.


Ativan: another common benzo (Lorazepam) that’s prescribed for anxiety, but also insomnia, and panic disorders. Mixing Ativan and alcohol can be dangerous because Ativan is central nervous system depressant. Taking it with alcohol can have an additive effect increasing the risk for drowsiness, confusion, and coma (43).


Ambien & Imovane: a.k.a. Zolpidem and Zopiclone, are similar prescription sleep aids (insomnia and sleep disorders) medications.  They are referred to as “sedative-hypnotics” which move a person into the in-between state of sleep and being awake.


Ambien and alcohol are commonly misused, intentionally and unintentionally, which enhances each other’s intoxicating effects. Major concerns include impaired cognition & judgment, somnambulance (sleepwalking), and depressed breathing (44).


Valium: or Diazepam, is also a benzo and prescribed for the same reasons Xanax, or Ativan are. As with those medications, Valium and alcohol is a potentially deadly mix for the same reasons. Do not mix the two (45).


Melatonin: while not a prescription medication in North America, melatonin is a hormone and still needs to be respected as a sleep aid supplement. Melatonin and alcohol ideally shouldn’t be mixed because the two can compound each other and increase drowsiness, dizziness and may aggravate anxiety. If you’ve had a couple of drinks, pass on the melatonin.


SSRIs, SNRIs, and NDRIs: so-called “mood stabilizers” are used to treat anxiety, depression, and NDRIs for ADHD, and narcolepsy. The cautions for this group of medications is the same as all of those in this list. Alcohol is a psychotropic drug (anything that can affect a person’s mental state) and as such, has a huge potential for interaction with any other class of psychotropic medications.


SSRI = selective serotonin reuptake inhibitors, SNRI = serotonin & norepinepherine reuptake inhibitors, and NDRI = norepinepherine & dopamine reuptake inhibitors


Brandy - Alcohol Effects On The Brain. What Are They?


Long term effects of alcohol

It’s impossible to put a hard number on it. No on can say for certain what the outcomes or risks will be for a given amount of alcohol consumed for a given period of time. The effects of alcohol on the brain will vary from person to person.


The effects of alcohol can be influenced by other things like personal health/health history, use of other drugs & medications, use of tobacco or cannabis, nutritional status and more.


The best evidence to date shows that drinking alcohol does not improve health. To varying degrees, alcohol consumption is associated with increased risk for weight gain, diabetes, dementia, pancreatitis, liver disease, malnutrition, high blood pressure, personal injury and vehicular accidents to name a few.


This of course will depend on how much, and how often, an individual drinks alcohol. Reducing risk is about following consumption patterns that are not associated with complications and poor health.


Doug Cook RDN is a Toronto based integrative and functional nutritionist and dietitian with a focus on digestive, gut, and mental health.  Follow me on FacebookInstagram and Twitter.