Seizures

This page is reference information compiled from the cited sources. It is not medical advice. For any decision about health, diagnosis or care, consult a qualified professional.

What it is

A seizure is a sudden burst of abnormal electrical activity in the brain that can cause a variety of symptoms. These symptoms range from brief lapses of awareness or muscle jerks to prolonged convulsions. Seizures are characterized by a tendency for recurrent, unprovoked episodes. According to a 2025 classification, seizures are grouped into four main classes: focal, generalized, unknown, and unclassified. Focal seizures originate in one area of the brain and may involve localized or distributed networks. Generalized seizures originate at a specific point within, and quickly spread across both hemispheres through interconnected brain networks.

Key facts

Epilepsy typically requires at least two unprovoked seizures occurring more than 24 hours apart for diagnosis. The underlying cause is often unknown, but can result from brain injury, stroke, infections, tumors, genetic conditions, developmental abnormalities, trauma, drowning, or an unidentified medical condition. As of 2024, approximately 50 million people worldwide have epilepsy, with nearly 80% of cases occurring in low- and middle-income countries. Epilepsy is more common in both children and older adults, and about 5–10% of people will have an unprovoked seizure by the age of 80. The chance of experiencing a second seizure within two years after the first is around 40%. Most cases of epilepsy, approximately 69%, can be effectively controlled with anti-seizure medications. For those whose seizures do not respond to drugs, other approaches, such as surgery, neurostimulation or dietary changes, may be considered.

When to seek professional help

Professional diagnosis involves ruling out other conditions that can resemble seizures. Diagnosis may include neuroimaging, blood tests, and electroencephalography. In some cases, epilepsy may be diagnosed after a single unprovoked seizure if clinical evidence suggests a high risk of recurrence. Seizure clusters, defined as multiple seizures occurring over a short period with incomplete recovery, are associated with increased emergency care utilization. The postictal state after a seizure is marked by confusion, headache, fatigue, or speech and motor disturbances, and postictal psychosis occurs in approximately 2% of individuals with epilepsy.

Source: Epilepsy (CC BY-SA 4.0 (Wikipedia)), retrieved 2026-09-23.