A seizure is an unregulated, abnormal electrical discharge in the brain that temporarily disrupts normal brain functioning. Seizures occur in the brain’s cortical gray matter but may affect several other regions of the brain.

About 10% of adults experience a seizure during their lifetime, but many of these people do not have another seizure. People may receive a seizure disorder diagnosis if they have more than one seizure or a condition that can cause multiple seizures. When a person has more than one seizure due to an external cause, that person has epilepsy.

This article discusses what seizure disorders are and the types of seizure disorders. It also provides information on treatment, symptoms, and when to contact a doctor.

Person on the floor after seizure.Share on Pinterest
Madrolly/Getty Images

Many conditions, disorders, and other factors can cause seizure or seizure disorders, such as:

  • cerebral edema (fluid buildup around the brain)
  • central nervous system (CNS) infections
  • brain malformations
  • genetic disorders
  • head trauma or injury
  • sores or tumors growing on the brain
  • exposure to toxins
  • certain drugs, such as CNS stimulants, sedating antihistamines, and antipsychotics
  • cerebral ischemia or hypoxia, which is when the brain is starved of oxygen
  • autoimmune disorders
  • stroke
  • withdrawal from alcohol
  • flashing lights, repetitive sounds, parts of music and video games, or, rarely, touch
  • metabolic and electrolyte disorders
  • lack of sleep
  • extreme stress

The most common causes of seizure disorders vary by age in many cases. Examples based on age include:

  • Less than 2 years old: Fever leading to febrile seizures, birth injuries involving the head, acquired or inherited metabolic disorders, and congenital neurological disorders.
  • 2–14 years old: Fever, tumors, and infections.
  • Adults: Tumors, stroke, head injury, and infections.
  • Older adults: Stroke, tumors, and neurodegenerative diseases such as Alzheimer’s disease.

There are three major types of seizure disorders:

Epileptic seizure disorder (ESD)

Epilepsy or ESD is a chronic neurological condition that causes someone to experience two or more seizures that are unprovoked, meaning they are not related to stressors or temporary disorders. Seizures resulting from ESD also occur more than 24 hours apart.

Learn more about epilepsy here.

Psychogenic nonepileptic seizures

Also called pseudoseizures, psychogenic nonepileptic seizures cause similar symptoms to seizures in people, but they are not due to abnormal electrical brain activity.

Learn more about pseudoseizures here.

Nonepileptic seizures

These are seizures that a certain stressing factor or temporary condition provokes. Some causes of nonepileptic seizures include:

  • metabolic disorders
  • cardiovascular disorders
  • central nervous system infections
  • sepsis
  • drug withdrawal or toxicity
  • psychogenic disorders, which are physical conditions that stem from emotional or mental stressors
  • fever in children

The International League Against Epilepsy (ILAE) created a new classification system for seizures in 2017. This system first classifies seizures based on the type of onset or where they originate in the brain.

The main types of seizures in the ILAE classification system are:

Generalized-onset seizures

Generalized-onset seizures originate in networks of brain nerve cells in both hemispheres, or sides, of the brain. Most people experience altered awareness, often to the point of losing consciousness. Generalized-onset seizures are then classified based on the symptoms they cause and whether they affect movement.

The main types of generalized-onset seizures are:

Tonic-clonic seizures

Tonic-clonic seizures can cause someone to have muscle twitching, jerking, spasming, or stiffening, often on both sides of the body. Many people become unconscious and fall to the ground or cry out during tonic-clonic-type seizures, which are also known as grand mal seizures.

Absence seizures

Absence seizures can cause rapid eye blinking and someone to “space” or “zone” out. Absence seizures are also called petit mal seizures.

Focalized-onset, or focal, seizures

Focal seizures originate in one side of the brain and may affect a small part or larger parts of the body. As with generalized-onset seizures, focal seizures tend to affect muscle movement and tone but usually only on one side of the body. Focal seizures can spread to involve both sides of the brain, called progression to tonic-clonic seizure.

The medical community further classifies focal seizures into two types, based on how they affect awareness or consciousness. The two types are focal aware seizures, which people formerly called simple partial seizures, and focal impaired awareness seizures, previously called complex partial seizures.

Unknown-onset seizures

Doctors classify seizures as unknown-onset seizures if they do not know how the seizure occurred or developed. As more information becomes available, a doctor may diagnose the person with focal or generalized seizures.

The type of seizure and the symptoms it produces can vary among individuals. Many people fall to the ground when they have a severe seizure. More minor seizures may only cause someone to feel odd or act oddly. Most seizures only last for a few seconds to minutes.

Many people who are having a seizure experience one or more of the following symptoms:

  • odd sensations, such as strange smells or tastes
  • altered awareness or consciousness
  • muscle spasms, jerks, or twitching in certain regions of the body
  • intense muscle stiffening or contracting involving the entire body, called convulsions
  • rapid blinking
  • crying out or being unable to speak
  • feeling confused, disoriented, or dazed
  • unexplained tiredness or sleepiness
  • spacing or zoning out
  • having very odd feelings that may be indescribable
  • out-of-body sensations, such as believing that the body feels different or looks odd, a detached sensation, or the feeling that people look familiar or strange when they should not
  • lapses in memory
  • numbness, tingling, or electric shocks in parts of the body
  • headaches
  • losing control of the bowels or bladder
  • hallucinations

Many people develop the following symptoms for a few minutes to hours after having a generalized-onset seizure:

  • deep sleep
  • muscle soreness or pain
  • confusion
  • muscle weakness

The best treatment plan for people with seizures or seizure disorders depends on the cause of the condition. Treatment options include:

  • eliminating the cause when possible, such as removing tumors, correcting malformations, treating infections or metabolic disorders, and removing excess fluid from around the brain
  • weaning off, or stopping, alcohol consumption or drug use
  • switching medications under a doctor’s direction
  • taking antiseizure medications to control seizures if two or more occur and other medications or surgery cannot eliminate or treat the cause
  • undergoing conventional epilepsy surgery if taking two or more antiseizure medications at therapeutic dosages does not control seizures
  • taking emergency medications to stop seizures if they last more than 5 minutes

Implanting medical devices may benefit people who cannot undergo surgery. These help control seizures by stimulating the left vagus nerve with a pacemaker-like device in combination with antiseizure medications. Implanting a programmable responsive neurostimulating device in up to two focal areas where seizures start can also stop seizure activity from happening before it starts.

Focal seizures that develop in parts of the brain that a surgeon can remove often improve significantly after surgery. Surgical treatment of seizures sometimes eliminates the further use of antiseizure medications. However, some people may still need to take the medications, though often in lower dosages or only one drug at a time.

Seizures can be scary and seem dangerous, but most seizures that are minor or only last a few seconds to minutes are harmless.

People with seizure disorders can do several things to help manage their seizures and reduce the risk of harm. Common management tips include:

  • going to a safe area away from furniture or anything else that could cause harm and lying down with a pillow under the head and loose clothing around the neck if a seizure is coming on
  • teaching family members, friends, and roommates to roll them onto their left side if they are having a seizure and not attempt to protect their tongue unless they are choking
  • avoiding activities that could cause serious harm if a seizure took place during them, such as swimming, having a bath, driving, climbing, using power tools, hiking, and cooking
  • avoiding stressors of seizures, such as drug or alcohol use
  • getting enough sleep
  • tracking seizures, including symptoms, duration, warning signs, potential stressors, and situations leading up to the seizure
  • reducing or managing stress

A person who does not have a diagnosis of a seizure disorder but experiences a seizure should contact a doctor as soon as possible. They should also contact a doctor if diagnosed seizures get worse, become more frequent, or cause new or different symptoms.

People who are around someone experiencing or recovering from a seizure must often decide whether to seek emergency care.

It is important to call 911 or take someone to an emergency department if they have:

  • a seizure that is longer than 5 minutes
  • never had a seizure before
  • a second seizure after the first one stops
  • sustained an injury during the seizure
  • a seizure in water
  • trouble breathing or walking after a seizure
  • other underlying medical conditions, such as heart disease and diabetes, or are pregnant

Several conditions can cause seizures and seizure disorders.

The World Health Organization (WHO) reports that with proper treatment, up to 70% of people with epilepsy could stop experiencing seizures by taking antiseizure medication.

People should contact a doctor if they have a seizure for the first time, or if their seizures worsen or change.

It is important to seek emergency care if someone has a seizure for more than 5 minutes, has multiple seizures back to back, or has trouble walking or breathing after a seizure.