The answer to whether alcohol can cause seizures is yes, though the relationship is neurologically complex. A seizure is a sudden, uncontrolled electrical disturbance in the brain caused by abnormal, excessive neuronal activity. Most seizures linked to alcohol consumption occur not during intoxication but when the body adjusts to the sudden absence of alcohol. This adjustment creates a state of dangerous hyperexcitability in the central nervous system.
How Alcohol Changes Brain Chemistry
Alcohol primarily interacts with the brain’s two most influential chemical signaling systems, regulating the balance between excitation and inhibition. The main inhibitory neurotransmitter is Gamma-aminobutyric acid (GABA), which acts like the brain’s natural brake pedal. Alcohol enhances GABA’s effects by binding to its receptors, making neurons less excitable and leading to sedative effects.
Alcohol also suppresses the activity of the major excitatory neurotransmitter, glutamate, particularly at the N-methyl-D-aspartate (NMDA) receptor. Glutamate is the brain’s accelerator; reducing its effect contributes to the overall reduction in neuronal activity and sedation. The combined effect of boosting the inhibitory system and suppressing the excitatory system causes the slurred speech, poor coordination, and memory impairment associated with acute intoxication.
Seizures Caused by Alcohol Withdrawal
The risk of seizure rises dramatically when a person with chronic, heavy alcohol use suddenly stops drinking, triggering alcohol withdrawal syndrome. Over time, the brain compensates for the constant presence of alcohol by making long-term adjustments. This involves downregulating the inhibitory GABA receptors, making them less responsive, and upregulating the excitatory glutamate receptors, making them more numerous and sensitive.
When alcohol is suddenly removed, the inhibitory brake is weak due to the downregulated GABA system. Simultaneously, the excitatory accelerator is slammed down by the now-hypersensitive glutamate system. This neurochemical imbalance results in profound hyperexcitability, causing neurons to fire uncontrollably and synchronously, leading to a seizure. These withdrawal seizures typically occur between 6 and 48 hours after the last drink, often presenting as generalized tonic-clonic seizures.
While a single seizure is the most common presentation, these events risk progressing to status epilepticus. Status epilepticus is a life-threatening condition where seizures last longer than five minutes or occur without a return to consciousness. Repeated cycles of heavy drinking and withdrawal can also lead to kindling, a progressive increase in seizure susceptibility with each subsequent withdrawal event. Withdrawal seizures are a significant risk factor for the later, more severe manifestation known as Delirium Tremens (DTs).
Alcohol Use and Existing Epilepsy
For individuals who already have epilepsy, alcohol consumption poses distinct risks separate from withdrawal syndrome. Heavy drinking, even without leading to withdrawal, can lower the seizure threshold, meaning the brain is more easily triggered. This effect makes existing epilepsy harder to control, increasing the frequency and severity of seizures. Binge drinking, in particular, is associated with a higher likelihood of triggering a seizure.
Alcohol also interferes with the management of epilepsy by interacting with anti-seizure medications (ASMs). Alcohol can reduce the effectiveness of these drugs, sometimes by altering drug levels in the bloodstream, causing them to fail to prevent seizures. Conversely, ASMs can increase the immediate effects of alcohol, causing intoxication more quickly and worsening side effects like dizziness and confusion.
When to Seek Medical Attention
Immediate medical attention is required for any seizure lasting longer than five minutes or for a series of seizures without the person regaining consciousness. This constitutes status epilepticus, a medical emergency. Because alcohol withdrawal seizures can rapidly escalate into life-threatening conditions, anyone who is a heavy, chronic drinker and experiences a seizure or severe signs of withdrawal needs professional help.
Signs such as severe tremors, hallucinations, extreme confusion, or agitation following a cessation of drinking should prompt an emergency room visit. Delirium Tremens (DTs) typically begins 48 to 72 hours after the last drink. DTs is the most severe form of withdrawal and is potentially fatal without medical intervention. Medical detoxification provides a safe, supervised environment where medications reduce brain hyperexcitability and prevent the progression to seizures and DTs.