Epilepsy is a brain condition in which neurons fire in abnormal, synchronized bursts, causing repeated seizures. It affects roughly 52 million people worldwide and is one of the most common neurological disorders at any age. A single seizure does not mean you have epilepsy. The diagnosis typically requires at least two unprovoked seizures more than 24 hours apart, or one seizure combined with a high likelihood (60% or greater) of having another within the next ten years.
What Happens in the Brain
Your brain runs on electrical signals. Neurons communicate by firing in coordinated patterns, with some cells sending excitatory signals (“go”) and others sending inhibitory signals (“stop”). In epilepsy, something disrupts that balance. A group of neurons begins firing excessively and in lockstep, overwhelming the brain’s normal checks. This runaway electrical activity is the seizure itself.
The process that transforms a healthy neural network into one prone to these bursts is called epileptogenesis. It can involve changes inside individual neurons, shifts in the chemical environment surrounding them, or problems with the support cells (called astrocytes) that help regulate brain chemistry. In a healthy brain, inhibitory neurons act like a feedback loop: when excitatory neurons fire, they trigger inhibitory neurons that dial the activity back down. When that feedback loop weakens or breaks, seizures become more likely.
Types of Seizures
Not all seizures look the same, and the type a person experiences depends on where in the brain the abnormal activity starts and how far it spreads.
- Focal seizures begin in one specific area of the brain. Some people remain fully aware during a focal seizure and simply notice unusual sensations, twitching in one limb, or a strange taste or smell. Others lose awareness and may stare blankly, make repetitive movements like lip-smacking, or seem confused for a minute or two.
- Generalized seizures involve both sides of the brain from the start. The most recognizable form is the tonic-clonic seizure (formerly called grand mal), where the body stiffens and then jerks rhythmically. Absence seizures are another generalized type, causing brief episodes of staring or subtle blinking that can be easy to miss, especially in children.
- Focal to bilateral tonic-clonic seizures start in one region and then spread across the entire brain. These were previously lumped in with generalized tonic-clonic seizures, but distinguishing them matters because the treatment approach can differ.
In some cases, doctors classify a seizure as “unknown onset” when there isn’t enough information to determine where it began. This isn’t a permanent label. It signals the need for further testing and follow-up rather than forcing a category that might be wrong.
What Causes Epilepsy
The causes fall into six broad categories: structural, genetic, infectious, metabolic, immune, and unknown. Many people with epilepsy have no identifiable cause at all.
Structural causes include anything that physically damages or alters brain tissue. A severe head injury, a stroke that cuts off oxygen to part of the brain, a tumor, or brain malformations present from birth all fall into this category. Birth complications, including oxygen deprivation or trauma during delivery, can also lead to epilepsy later in life.
Genetic epilepsy runs in families or arises from new gene mutations. Some genetic syndromes carry a high risk of seizures as part of a broader constellation of symptoms. Infections like meningitis, encephalitis, or parasitic infections of the brain are significant causes globally, particularly in lower-income countries where about 82% of new epilepsy cases occur. Immune and metabolic causes are less common but include conditions where the body’s immune system attacks brain tissue or where metabolic disorders disrupt normal brain function.
How Epilepsy Is Diagnosed
The cornerstone test is an electroencephalogram, or EEG, where small electrodes placed on the scalp record the brain’s electrical activity. People with epilepsy often show characteristic changes in their brainwave patterns, even between seizures. A high-density version of this test places electrodes closer together to pinpoint exactly which brain areas are involved.
Brain imaging fills in the structural picture. An MRI creates a detailed view of brain anatomy, revealing tumors, scar tissue, or malformations that might be triggering seizures. CT scans can quickly detect bleeding or cysts. In some cases, specialized scans that measure blood flow or metabolic activity in the brain help locate the precise zone where seizures originate. These are particularly useful when surgery is being considered.
Blood work and genetic testing can uncover infections, metabolic problems, or inherited conditions linked to seizures. Neuropsychological tests, which assess memory, thinking, and language skills, help determine which brain regions are affected and serve as a baseline before treatment.
Treatment and Seizure Control
Medication is the first line of treatment, and the numbers are encouraging. About 47% of people with newly diagnosed epilepsy become seizure-free on their first medication. If that doesn’t work, trying a second or third option brings the overall seizure-freedom rate up to roughly 88%. A large study of 459 newly diagnosed patients found that among the 151 who didn’t respond to the first medication, nearly two-thirds eventually achieved seizure control after trying an average of two additional medications.
For the remaining 10 to 12% whose seizures resist medication, other options exist. Surgery to remove or disconnect the small area of brain tissue causing seizures is effective for some people, particularly those with focal epilepsy that originates from one identifiable spot. Devices that deliver electrical stimulation to the brain or a nerve in the neck can reduce seizure frequency. Dietary approaches, especially a high-fat, very-low-carbohydrate diet, have shown benefit in some cases, particularly in children.
Can Epilepsy Go Away?
Yes, in some cases. Epilepsy is considered resolved when a person has been seizure-free for at least 10 years and has been off medication for at least 5 of those years. This doesn’t necessarily mean the underlying brain changes have disappeared, but it does mean the condition is no longer active. Some childhood epilepsy syndromes are particularly likely to resolve by adulthood.
Living Safely With Epilepsy
One of the more serious risks is sudden unexpected death in epilepsy, or SUDEP. It’s uncommon, affecting roughly 1 in 1,000 adults with epilepsy per year and about 1 in 4,500 children. The biggest risk factors are frequent uncontrolled seizures and generalized seizures, which is one reason consistent medication use matters so much. Having seizures during sleep, living with epilepsy for many years, and missing medication doses also increase the risk.
What to Do if Someone Has a Seizure
If you witness a seizure, stay calm and stay with the person. Move nearby objects that could cause injury. If they’re on the ground, gently roll them onto their side with the mouth pointing downward to keep the airway clear. Place something soft under their head, remove their glasses, and loosen anything tight around their neck. Time the seizure. If it lasts longer than five minutes, call emergency services.
Equally important is what not to do. Never hold the person down or try to restrain their movements. Don’t put anything in their mouth, as this myth persists but can actually cause tooth or jaw injuries. Don’t attempt mouth-to-mouth breathing during the seizure, and don’t offer food or water until the person is fully alert. Once the seizure ends, help them sit somewhere safe, explain what happened, and offer to help them get home.