A Complete Overview of Generalized Seizures

Medically Reviewed By Seunggu Han, M.D.
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Generalized seizures affect both sides of the brain at the same time. People experiencing a generalized seizure may lose consciousness, fall to the ground, and have intense muscle contractions. Seizures are uncontrolled bursts of electrical activity in the brain and are the main symptom of epilepsy. The two main types are focal and generalized seizures.

This article explains the differences between focal and generalized seizures. It also looks at the types of generalized seizures and potential causes and triggers. Read on to learn about treatments and the outlook for someone who experiences generalized seizures.

Focal vs. generalized seizures

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Focal seizures, also known as partial seizures, are electrical disturbances in only one side of the brain. About 60% of people with epilepsy have focal seizures.

During a focal seizure, there is no loss of consciousness. The person may experience physical, sensory, or psychic feelings. For example, they may feel intense déjà vu, emotions, or nausea. Sometimes they also taste, feel, or see things that are not there. 

Generalized seizures are widespread electrical discharges that affect both sides of the brain. Several types of generalized seizures exist.

Generalized tonic-clonic seizures

A generalized tonic-clonic seizure, formally known as a “grand mal seizure,” includes a tonic phase of muscle stiffening followed by a clonic phase of muscle twitching or jerking. 

The Epilepsy Foundation states that these seizures typically last 1–3 minutes and can last up to 5 minutes, resulting in a medical emergency. 


Generalized tonic-clonic seizures feature a tonic phase followed by a clonic phase. 

The tonic phase symptoms include:

  • stiffening of all the muscles
  • a cry or groan as air is forced past the vocal cords
  • loss of consciousness
  • possible biting of the tongue or cheek

The clonic phase symptoms include:

  • rapid jerking of the arms and legs for several minutes
  • possible frothing at the mouth
  • possible loss of bladder or bowel control
  • irregular breathing pattern
  • possible dusky color of the face if they are having trouble breathing
  • slow return of consciousness 

Call 911 if a seizure lasts 5 minutes or longer or if there are multiple seizures in a row.

After experiencing a seizure, the person will feel sleepy and need rest. They may be difficult to rouse and can feel confused, irritable, or depressed. This stage can last a few hours up to a couple of days.   

Learn more about generalized tonic-clonic seizures

Tonic seizures

Tonic seizures involve increased muscle tone and limb stiffening. They typically last less than 20 seconds but can last up to 2 minutes. This type of seizure often occurs in people while they are sleeping and can vary in intensity.


Tonic seizures symptoms include:

  • stiffening of the body, arms, and legs
  • often occur during sleep
  • can cause falls or injury

Clonic seizures

Clonic seizures involve rhythmic muscle jerking without the tonic phase of muscle stiffness. Clonic seizures typically last a few minutes and can cause loss of consciousness.


Clonic seizure symptoms may include:

  • jerking movements of the arms and legs
  • irregular breathing
  • frothing at the mouth
  • loss of consciousness

Atonic seizures

During an atonic seizure, the muscles completely relax. Some people call these “drop seizures” or “drop attacks” because they cause the person to fall to the floor. People who experience these seizures often wear helmets to protect themselves from head injuries.


The main symptom is a loss of muscle tone, often causing the person to fall to the floor. These seizures usually last under 15 seconds.

Learn more about atonic seizures.

Myoclonic seizures

Myoclonic seizures are similar to clonic seizures. However, they last only for a few seconds and typically do not cause the person to lose consciousness. They can occur as one isolated seizure or in a cluster of several seizures.


Myoclonic seizures involve shock-like jerks of muscles that last for a few seconds. They typically affect the upper body but can also affect the whole body.

Learn more about myoclonic seizures.

Absence seizures

Unlike other seizures, absence seizures do not affect the muscles but cause a lapse in awareness and activity. They typically last only for a few seconds.


A person experiencing an absence seizure may lose awareness and activity for a few seconds. They may stare into space or blink rapidly and often look like they are zoning out or daydreaming.

Learn more about absence seizures.

Myoclonic-atonic seizures

A myoclonic-atonic seizure includes a myoclonic seizure followed by an atonic seizure. This results in a series of shock-like jerks, complete muscle relaxation, and often a drop attack. After their onset, this type of seizure typically increases in frequency, with 10 to 50 seizures daily. 


Symptoms may include:

  • jerking muscle contractions
  • loss of consciousness 
  • sudden loss of muscle tone
  • falling to the ground
  • possible loss of bowel or bladder control

Learn more about all types of epilepsy


Sudden bursts of electrical activity in the brain cause seizures. Currently, experts do not know the cause of these sudden bursts. However, they do believe genetics may play a role. 

Several other conditions may cause seizures, including:

  • head injuries
  • brain tumors
  • infections in the brain
  • stroke
  • birth irregularities
  • prescription medications


While the cause of seizures can vary, certain things may trigger seizures, including:

Learn more about seizure causes and triggers.


Treating seizures vary depending on the cause. 

Options for treatment may include:

  • anti-epileptic drugs 
  • surgical removal of the part of the brain causing the seizures
  • vagus nerve stimulation
  • deep brain stimulation
  • ketogenic diet

Your medical professional will review your treatment options with you and discuss the various risks of each treatment.

Learn more about treatments for epilepsy.


The outlook for people with epilepsy varies depending on the type of seizure. Many people with epilepsy can control their seizures using medications or other treatments and live successful and productive lives. However, the Epilepsy Foundation discusses some complications, such as:

  • mood swings
  • difficulty sleeping
  • trouble with thinking or memory
  • socialization complications
  • loss of driving privileges
  • sudden unexpected death in epilepsy (SUDEP)

Learn more about how seizures affect your body.


Generalized seizures involve the whole brain. Focal seizures affect one-half of the brain. Several types of generalized seizures exist, which cause the body to act in various ways, including muscle spasms, contraction, or complete muscle relaxation.

While the cause of seizures is unknown, several known risk factors include head injuries, tumors, and infections. In addition, seizures can have several triggers, including environmental triggers or illness.

Treatment for generalized seizures may include medications, surgery, and diet changes. 

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Medical Reviewer: Seunggu Han, M.D.
Last Review Date: 2022 Oct 28
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