“Fits” is a common, informal term for seizures, episodes of abnormal electrical activity in the brain that cause involuntary changes in movement, sensation, behavior, or consciousness. It is not a single disease but a symptom that can arise from many different conditions. When fits occur repeatedly without a reversible cause, the underlying condition is called epilepsy, which affects roughly 4 to 10 out of every 1,000 people worldwide.
What Happens in the Brain During a Fit
A seizure occurs when a large group of brain cells fire electrical signals at the same time in an abnormal, synchronized burst. Normally, your brain maintains a careful balance between signals that excite nerve cells and signals that calm them down. A fit happens when that balance tips too far toward excitation. This can result from overactive excitatory signaling, reduced inhibitory signaling, changes in the ion channels that control nerve cell firing, or shifts in the chemical environment around brain cells.
The specific symptoms depend on where in the brain the abnormal activity starts and how far it spreads. A burst confined to one area might cause twitching in a single hand or a brief moment of confusion. When the activity spreads across the entire brain, the result is a generalized seizure with full-body convulsions and loss of consciousness.
Types of Fits
Seizures fall into a few broad categories based on where they originate and what they look like.
Focal seizures start in one specific area of the brain. You might remain fully conscious during a focal seizure, experiencing unusual sensations, jerking in one limb, or a strange taste or smell. In other cases, consciousness is impaired, and you may stare blankly, make repetitive movements like lip-smacking, or be unable to respond to people around you.
Generalized seizures involve both sides of the brain from the start. The most dramatic type is a tonic-clonic seizure (sometimes called a “grand mal”), which involves stiffening of the body followed by rhythmic jerking, often with loss of consciousness. Absence seizures are another generalized type, common in children, where the person briefly zones out for a few seconds before snapping back to normal. Other generalized types include sudden muscle jerks (myoclonic seizures) or a sudden loss of muscle tone that causes the person to drop to the ground.
Common Causes and Triggers
Fits can be provoked by a wide range of conditions. Some of the most common causes include head injuries, stroke, brain infections like meningitis, brain tumors, and genetic factors. In children, certain genetic and metabolic conditions can cause epilepsy from a young age. Autoimmune processes, where the body’s immune system attacks brain tissue, are another recognized cause. In many cases, no specific cause is ever identified.
For people who already have epilepsy, certain triggers make seizures more likely. These include sleep deprivation, psychological stress, alcohol withdrawal, flashing or flickering lights, hyperventilation, and missing doses of seizure medication.
Febrile Fits in Children
One of the most common and frightening types of fits for parents to witness is the febrile seizure. These occur in children between 6 months and 5 years old during a fever above 100.4°F (38°C). They are not caused by a brain infection or any other underlying neurological problem. Each child has their own temperature threshold for triggering a febrile seizure, so there is no single “danger temperature” that applies to everyone.
Febrile seizures are generally brief and do not cause lasting harm. Most children who have one will not go on to develop epilepsy. Still, a first febrile seizure warrants medical evaluation to rule out serious infections.
How Fits Are Diagnosed
Diagnosing the cause of fits typically starts with a detailed medical history and a neurological exam that evaluates behavior, movement, and mental function. The most important test is an EEG (electroencephalogram), which records the brain’s electrical activity through sensors placed on the scalp. An EEG can reveal characteristic patterns that help identify the type of seizure and where in the brain it originates. Sometimes the test is done over several days at home with a portable device, and you may be asked to sleep less than usual beforehand, since sleep deprivation can trigger detectable seizure activity.
Brain imaging is the other key piece of the puzzle. An MRI scan looks for structural abnormalities like scar tissue, tumors, or malformations that could be triggering seizures. In some cases, additional imaging such as a functional MRI, PET scan, or CT scan is used to pinpoint the seizure focus more precisely. For children, doctors may also investigate genetic or metabolic causes through blood tests.
Treatment Options
Anti-seizure medications are the first-line treatment for most people with epilepsy, and they successfully control fits in about two-thirds of patients. These medications work by restoring the balance between excitatory and inhibitory brain activity. Some stabilize nerve cells by preventing them from firing too rapidly. Others boost the brain’s natural calming signals, making it harder for a seizure to gain momentum. Still others reduce the release of chemical messengers at nerve connections, dampening overactive circuits.
Finding the right medication often takes some trial and adjustment. The goal is to stop seizures entirely with the fewest side effects, and many people take a single daily medication long-term. For people whose seizures do not respond to medication, other options include surgery to remove or disconnect the brain area where seizures start, nerve stimulation devices, or specialized diets like the ketogenic diet, which alters brain metabolism in ways that reduce seizure activity.
What to Do If Someone Has a Fit
Knowing how to respond when someone has a seizure can prevent injury. The most important steps are to stay calm, stay with the person, and protect them from their surroundings. Move sharp objects or furniture out of the way. If they fall or are lying down, gently roll them onto their side with their mouth pointing toward the ground so their airway stays clear. Place something soft under their head, remove their glasses, and loosen anything tight around their neck.
Time the seizure from the moment it starts. If it lasts longer than 5 minutes, call emergency services. This threshold marks a condition called status epilepticus, which requires immediate medical treatment because the brain can be damaged by prolonged seizure activity.
Equally important is what not to do. Never hold the person down or try to restrain their movements. Do not put anything in their mouth, as this is an old myth that can damage teeth or the jaw. Do not attempt mouth-to-mouth breathing during the seizure, as normal breathing almost always resumes on its own once the episode ends. Wait until the person is fully alert before offering water or food, since swallowing is impaired during recovery and choking is a real risk.
Once the seizure is over, help the person sit somewhere safe. They will likely be confused, drowsy, or disoriented for several minutes to an hour afterward. Calmly explain what happened and offer to help them get home.