A seizure is a sudden, time-limited disturbance of brain function caused by excessive, synchronized electrical activity of nerve cells. Depending on which brain regions are involved, a seizure may present with involuntary muscle contractions, loss or alteration of consciousness, sensory disturbances, or autonomic symptoms such as sweating and rapid heartbeat. Seizures are symptoms, not a disease in themselves.
How do seizures develop in general? #
Normal brain function depends on a finely balanced interaction between excitatory and inhibitory neural signals. Seizures occur when this balance shifts toward excessive excitation and overall neuronal excitability increases. Common underlying causes include:
- – structural brain damage (for example after stroke, trauma, or tumors)
- – metabolic disturbances (such as hypoglycemia or electrolyte imbalances)
- – inflammatory or infectious processes
- – genetic predisposition
- – toxic influences or withdrawal states
All of these factors have one thing in common: they lower the seizure threshold or weaken inhibitory control mechanisms in the brain.
Why is there a risk of seizures during alcohol withdrawal? #
Alcohol has a central nervous system depressant effect. It enhances inhibitory neurotransmission while simultaneously suppressing excitatory signaling. With regular alcohol consumption, the brain adapts to this constant depressant influence:
- – inhibitory systems are downregulated
- – excitatory systems are upregulated
When alcohol intake is suddenly stopped, its dampening effect disappears abruptly. What remains is a hyperexcitable nervous system that cannot immediately restore balance. This can result in massive neuronal overactivity, which may clinically manifest as an alcohol withdrawal seizure.
Such seizures typically occur 24 to 72 hours after the last drink, often without warning and largely independent of how severe the person subjectively perceives the withdrawal to be.
Why does the risk increase with longer drinking history and repeated withdrawals? #
The longer and more regularly alcohol is consumed, the more pronounced the neurobiological adaptations in the brain become. Each withdrawal episode represents another phase of extreme neural overexcitability. With repeated withdrawals, the nervous system becomes increasingly sensitized:
- – the seizure threshold continues to drop
- – seizures occur earlier and with less provocation
- – each withdrawal tends to be more severe than the last
This process is known as the kindling effect. It explains why even relatively short drinking episodes can lead to serious withdrawal complications in individuals with a history of long-term alcohol use or multiple prior withdrawals.
Bernd Guzek, MD, PhD #
Physician, author & co-founder of Bye-Bye-Booze
Specialized in biochemical mechanisms of addiction and brain metabolism.
