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Alcohol & Its Effects on the Nervous System

Alcohol is a central nervous system depressant. It works by suppressing key signals this system needs to control thoughts, movements, memories, and more.

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But what is the central nervous system (CNS)? We’ll explain how this core part of your body works. And we’ll outline the short-term and long-term changes alcohol can cause. If you’ve been struggling with alcohol abuse, this information could be enough to prompt a change. 

The Nervous System Defined 

The central nervous system is responsible for receiving, processing, and responding to sensory information.[2] Alcohol works directly on this system, slowing it down and altering how it works. 

Two main elements make up the CNS: the brain and the spinal cord. 

The Brain 

The brain is housed within the thick protection of the skull. It’s one organ, but it’s made up of two sides:[2]

  • Left hemisphere: This half controls language, logic, and mathematical abilities. 
  • Right hemisphere: This half controls artistic abilities and musical situations. 

These two sides are in constant communication, using neurotransmitters (chemicals) and electrical impulses to trade information. 

The Spinal Cord 

The spinal cord is made up of fibers protected by bony structures we call the spine. The following two pathways are used within the spinal cord:[2]

  • Ascending: Information from the body travels up nerve bundles in the spinal cord to the brain. Sensations like pressure, pain, and temperature move up this pathway. 
  • Descending: Signals from the brain move down nerve bundles via the spinal cord. These prompts enervate muscles to twitch so you can move. 

Short-Term Effect of Alcohol Use 

Ingesting a CNS depressant like alcohol can alter the way this key system works, changing almost everything about the way you perceive and interact with the world around you. These are some of the changes people experience: 

Impaired Movement 

Alcohol works directly on the portions of the brain that control balance.[3] Brain cells may send signals down the descending pathway to entice muscles to move. But those prompts may be too weak or erratic to be interpreted properly. 

Acute intoxication causes people to move slowly and clumsily. Injuries are common due to alcohol. And detailed tasks, such as driving, could be impossible. 

Impaired Judgment 

Drinking alcohol slows portions of the brain that control information processing and social cues.[4] People make decisions while intoxicated that they would never support while sober. CNS adjustments are to blame. 

People who are intoxicated may say or do things with others that they regret later. When their brain cells start working normally, they may regret ever drinking.

Memory Loss 

Drinking too much can lead to an alcohol-related blackout. These memory gaps are dose-dependent, so the more you drink, the longer they last. 

Memory loss occurs when alcohol blocks the transfer of memories from short-term to long-term storage. The hippocampus, deep within the brain, tackles this role.[3] When it’s sedated by alcohol, it can’t function properly. 

Long-Term Effects of Alcohol Abuse 

Drinking alcohol just once can alter the CNS. People who keep drinking can develop even more significant problems, including some that aren’t treatable. These are some of those issues:


Researchers say alcohol is the second-leading cause of dementia. Only Alzheimer’s disease causes more cases.[5] 

Poor nutrition could be to blame. People with severe alcoholism consume up to 50% of their daily calories in alcohol. They can have severe nutritional deficiencies that lead to brain cell death.[5]

But brain cells constantly hampered and sedated by alcohol can get smaller and smaller.[5] These shrunken sections can’t do their job as well. Poor cognitive function, considered dementia, is the result. 

Premature Aging 

All brains get smaller and less effective with age. But drinking alcohol regularly can accelerate this process. Brain segments shrink, and fewer neurons communicate with one another.[5] 

While this process can’t be reversed in an aging brain, people who drink can allow their cells to heal by quitting their alcohol habit. 

Poor Decision-Making 

While it’s clear that people make poor decisions while intoxicated, the problem worsens in those who keep drinking without quitting. 

In studies of chronic drinkers, people made poor decisions and risky choices when compared to healthy controls.[6] Portions of the brain dealing with impulse control and decision-making are shrunken and altered due to longstanding abuse. 

This altered part of the brain can solidify alcohol abuse. People who can’t make good choices may keep drinking because their brain cells can no longer discern between a good choice and a poor one.

Seizure Disorders 

Brain cells long sedated by alcohol can struggle to function normally during periods of sobriety. When people with alcoholism try to quit, they can develop seizures as their brain cells reawaken. 

Researchers say seizures usually peak between 12 and 48 hours after people stop drinking.[7] They can recur, so one seizure is followed by another very quickly. Brain cells are damaged with each episode, and without treatment, seizures can become life-threatening. 


Chronic alcohol abusers can experience episodes of shaking, followed by visual or auditory hallucinations, when they try to quit drinking. In severe cases, these symptoms can appear when people haven’t had a drink for a few hours. 

Symptoms typically peak between 6 and 24 hours after quitting drinking.[7] But if they grow more severe, seizures may begin. People who begin to shake should get treatment quickly. 

Unfortunately, some people with alcoholism use the shakes and shivers as a prompt to drink even more. These episodes can be frightening, and some people become convinced that quitting alcohol just isn’t safe for them. 

When to Seek Help for Alcohol Abuse 

Anyone who thinks they need help to quit drinking can benefit from treatment. It’s never too early or too late to ask for help. But some people need a little extra push. Understanding how doctors diagnose alcohol use disorders could help you determine if you need help

Doctors use questions to determine whether their patients meet diagnostic criteria for alcoholism. The more questions you answer with “yes,” the more likely it is that you will need treatment. 

Answer the following questions as carefully and honestly as you can. Within the last year, have you:[8]

  1. Drank more alcohol than you planned to? 
  2. Felt unable to quit drinking, even when you want to?
  3. Spent a lot of time getting, using, or recovering from alcohol?
  4. Experienced cravings for alcohol?
  5. Felt unable to fulfill your obligations due to alcohol?
  6. Kept drinking even when you knew alcohol was harming your life?
  7. Spent less time on social, occupational, or recreational activities due to alcohol?
  8. Used alcohol in dangerous situations?
  9. Felt the need to drink more to get drunk?
  10. Experienced discomfort when you tried to quit drinking?

If you’ve answered “yes” to even some of these questions, it’s time to consider a treatment program. With the help of trained professionals, you can learn more about how alcohol works and what you’ll need to do to stop using it. In serious cases, doctors can use medications to ease cravings too.

If you have AUD, it’s not safe to simply stop drinking on your own. This could trigger life-threatening withdrawal symptoms. Talk to a doctor or reach out to an alcohol addiction treatment program before you stop drinking. They can guide you through the process, ensuring your safety and success along the way. 

As you stop drinking, your brain cells can heal. And with counseling and education, you can learn more about how to live with brain cells that are impaired. Your life can get better, but you have to first reach out for that help. We’re ready to take your call.

Updated March 21, 2024
  1. Costardi JV, Nampo RA, Silva GL, et al. A review on alcohol: from the central action mechanism to chemical dependency. Rev Assoc Med Bras (1992). 2015;61(4):381-387. doi:10.1590/1806-9282.61.04.381
  2. Anatomy, central nervous system Thau L, Reddy V, Singh P. StatPearls. Published October 10, 2022. Accessed September 22, 2023
  3. Alcohol and the brain: An overview National Institute on Alcohol Abuse and Alcoholism. Published 2022. Accessed September 22, 2023
  4. Acute effects of alcohol on social and personal decision making Karlsson H, Persson E, Perini I, et al. Neuropsychopharmacol. 2022:47:824–831
  5. Pervin Z, Stephen JM. , Effect of alcohol on the central nervous system to develop neurological disorder: pathophysiological and lifestyle modulation can be potential therapeutic options for alcohol-induced neurotoxication, AIMS Neurosci. 2021;8(3):390-413. Published 2021 Apr 9. doi:10.3934/Neuroscience.2021021
  6. Brevers D, Bechara A, Cleeremans A, Kornreich C, Verbanck P, Noël X. Impaired decision-making under risk in individuals with alcohol dependence, Alcohol Clin Exp Res. 2014;38(7):1924-1931. doi:10.1111/acer.12447
  7. Alcohol and the nervous system McIntosh C, Chick J., Journal of Neurology, Neurosurgery & Psychiatry. 2004;75:iii16-iii21.
  8. Diagnostic criteria checklist Rand Corporation. Published June 2021. Accessed September 22, 2023
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