Why Alcohol Withdrawal can Trigger Grand Mal Seizures


woaman suffring Seizures
When someone who has been drinking heavily for a long time stops suddenly, their brain can react badly. This is alcohol withdrawal, and one of the most serious potential symptoms is an alcohol withdrawal seizure. There are a few different types of seizures that alcohol withdrawal can cause, but the most common is called a generalised tonic-clonic seizure, though many people still know them by the older term, grand mal seizures. These affect the whole body, causing loss of consciousness, and potentially serious injury or even death if they happen without medical support nearby.

To make sense of why this happens, it helps to know what alcohol does to your brain during prolonged heavy drinking, and why stopping suddenly is so dangerous.

What alcohol does to the brain

Alcohol is a central nervous system depressant, which means it slows brain activity down. It does this mainly by boosting the effects of a chemical messenger called GABA, which calms brain activity, while at the same time dampening glutamate, which speeds things up. That is why many people feel relaxed or sedated when they drink.

The problem is that the brain does not like being pushed in one direction for too long. If you drink heavily day after day, your brain starts to push back. It reduces its sensitivity to GABA, so calming signals have less effect, and it increases its sensitivity to glutamate, so excitatory signals become stronger. This is the brain’s attempt to keep balance despite the constant presence of alcohol, but these alcohol dependence brain changes cause problems when you stop.

While alcohol is still present, the rebalancing act works well enough. But when alcohol suddenly disappears, the brain is left in a state it was never designed for. GABA is weak, glutamate is overactive, and there is nothing to keep the system in check. What you are left with is a GABA glutamate imbalance that sends the whole nervous system into overdrive, which is why the neurological effects of alcohol withdrawal can be so severe.

When seizures are most likely to happen

Acute withdrawal symptoms usually start within about six to twelve hours of your last drink, beginning with anxiety, tremors, sweating, nausea, and a racing heart. For most people, these symptoms are deeply unpleasant but not life-threatening. However, as the hours pass and your brain becomes increasingly overactive, the chance of more serious withdrawal complications goes up.

The seizure risk during alcohol withdrawal is highest between six and forty-eight hours after your last drink, with the danger peaking somewhere around the twenty-four to forty-eight hour mark. Research suggests that more than 90% of alcohol withdrawal seizures occur within this window. They often come without warning, and in more than half of cases, a person will have more than one seizure in quick succession.

These are tonic-clonic seizures, which means they involve two phases. In the tonic phase, the muscles stiffen, and the person loses consciousness. In the clonic phase, the body jerks rhythmically. The whole event usually lasts one to three minutes, but it can feel much longer to loved ones who witness it, and the person who has the seizure will have no memory of it afterwards.

Additional Read: Quitting Alcohol Timeline

Risk factors for alcohol withdrawal seizures

Not everyone who stops drinking will have a seizure, and while estimates vary, around 3-10% of people going through alcohol withdrawal will experience one. However, there are some things that make seizures much more likely.

Drinking history
People who have been drinking heavily for years are at greater risk of seizures. The body has had more time to adapt to the presence of alcohol, which means the alcohol dependence brain changes are greater, and the rebound when alcohol is removed is more severe.
Previous withdrawal episodes
A person who has been through withdrawal several times before is at much higher risk than someone going through it for the first time, even if their current drinking level is similar. This is due to a phenomenon called the kindling effect. Each time a person goes through alcohol withdrawal, the brain reacts more strongly. Symptoms tend to be worse each time it happens, and it takes less to set off a seizure.
Age and existing health problems
Older people and those with problems involving the heart, liver, or nervous system tend to have higher alcohol detox risks.
Electrolyte imbalances and dehydration
These are common after drinking heavily for a long time, and they can affect how the brain works.

woman lost consciousness

The relationship between seizures and delirium tremens

Alcohol withdrawal seizures are closely related to delirium tremens, often called DTs. This is the most severe form of alcohol withdrawal that typically appears around two to four days after the last drink. DTs involve severe confusion, agitation, hallucinations, fever, and the heart rate and blood pressure can become dangerously unstable. Only about 5% of people going through alcohol withdrawal develop full delirium tremens, but when it happens, it is a medical emergency.

Seizures can occur as part of delirium tremens, but they more commonly happen before it sets in. In fact, having a withdrawal seizure is one of the warning signs that someone might go on to develop delirium tremens if they do not receive medical care. This is one of the reasons why any seizure during alcohol withdrawal should be treated very seriously, even if the person seems to recover quickly afterwards.

Why medical monitoring matters

The difficult thing about alcohol withdrawal seizures is that they are so unpredictable. A person who has gone through withdrawal before without any problems can still have a seizure the next time. Someone who drinks less than another person might still be at higher risk due to other factors. There is no way to know in advance exactly how someone’s body will respond to the sudden absence of alcohol.

This is why medically monitored detox is so important. In a medical setting, staff can observe for early warning signs of worsening withdrawal, give medications that make seizures and other complications much less likely, and respond immediately if something does go wrong. The medications most commonly used, particularly benzodiazepines, work on the same GABA system that alcohol affects, which helps to ease the brain’s transition and reduce that dangerous state of overactivity.

Trying to stop drinking suddenly at home, especially after a long period of heavy use, carries real alcohol detox risks. Even a person who feels determined and prepared can find themselves in serious trouble suddenly. A seizure that happens when no one else is around can result in head injuries, choking, breathing problems, and death.

Detox safely from alcohol with Banbury lodge

If you or someone you care about has been drinking heavily and wants to stop, the safest path is always to seek medical support. A medically planned and monitored detox does not just reduce the chance of grand mal seizures and delirium tremens. It also gives you a solid start on recovery, connecting you with the support and treatment you need to stay well in the longer term.

Alcohol withdrawal is one of the few types of substance withdrawal that can actually be life-threatening. That is not said to frighten anyone, but to make clear why professional help matters. With the right support, it is possible to get through withdrawal safely and move forward into a healthier life. Contact us today to find out more about alcohol detox and rehab treatment with Banbury lodge.

(Click here to see works cited)

  • Jesse, Sven, et al. “Alcohol Withdrawal Syndrome: Mechanisms, Manifestations, and Management.” Acta Neurologica Scandinavica, vol. 135, no. 1, 2017, pp. 4–16. https://doi.org/10.1111/ane.12671.
  • Rogawski, Michael A. “Update on the Neurobiology of Alcohol Withdrawal Seizures.” Epilepsy Currents, vol. 5, no. 6, 2005, pp. 225–230. https://doi.org/10.1111/j.1535-7511.2005.00071.x.
  • “Alcohol Withdrawal Syndrome.” StatPearls, National Center for Biotechnology Information, 14 Feb. 2024, https://www.ncbi.nlm.nih.gov/books/NBK441882/.
  • “Kindling in Alcohol Withdrawal.” Alcohol Research & Health, vol. 22, no. 1, 1998, pp. 25–33. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6761822/.
close help
Who am I contacting?

Calls and contact requests are answered by admissions at

UK Addiction Treatment Group.

We look forward to helping you take your first step.

0203 826 8381