What Causes Seizures in Adults? 10 Possible Triggers and Conditions

What Causes Seizures in Adults? 10 Possible Triggers and Conditions

Causes of seizures in adults are far more varied than most people expect. A seizure is a sudden burst of abnormal electrical activity in the brain, and it can happen to anyone with a vulnerable brain, whether or not they have ever been diagnosed with a neurological condition. For some adults the cause is a long-term disorder such as epilepsy. For others it is a stroke, a head injury, a medication, a metabolic problem, or even a few nights of very poor sleep.

If you or someone you love has just had a first seizure, you probably have a lot of questions. Why did it happen? Will it happen again? Is it epilepsy? This guide walks through the most important causes of seizures in adults, explains how doctors find the answer, and tells you when to seek help right away.

Consultant Corner is led by Saqib A. Chaudhry, MD, a vascular neurologist and neuro-intensivist. Our neurology team cares for patients at two locations: Neurological Care in Bloomington, IL (Neurologist in Bloomington, Illinois) and Neurological Care in El Paso, TX (Health consultant in El Paso, Texas). Below, we share what we want every patient to understand about this frightening but very evaluable symptom.

What Is Epilepsy? Understanding Seizures First

Before looking at the causes of seizures in adults, it helps to separate two terms that people often use as if they meant the same thing.

A seizure is a single event. It happens when nerve cells in the brain fire in an abnormal, uncontrolled way for a short period. Depending on which part of the brain is involved, a seizure can cause shaking, stiffening, staring, confusion, strange sensations, or a loss of awareness.

Epilepsy is a condition. It is diagnosed when a person has a tendency toward repeated, unprovoked seizures. In general, doctors diagnose epilepsy after two or more unprovoked seizures, or after one seizure when testing shows a high risk of another. You can read a deeper overview in our page on What is Epilepsy? and in our article Epilepsy and Seizures: 10 Facts.

This distinction matters because many causes of seizures in adults have nothing to do with epilepsy. A seizure caused by very low blood sugar, severe dehydration, or alcohol withdrawal is called a provoked or acute symptomatic seizure. Once the trigger is treated, the seizures may never return.

The Two Main Seizure Types in Adults

Seizures are grouped by where they begin in the brain. Knowing the type helps your neurologist look for the right cause.

• Focal seizures begin in one area of the brain. You may stay aware, or you may have impaired awareness. Symptoms can include twitching in one hand, a strange smell or taste, a rising feeling in the stomach, déjà vu, or sudden confusion.
• Generalized seizures involve both sides of the brain from the start. The best-known type is the tonic-clonic seizure, with stiffening followed by rhythmic jerking and loss of consciousness. Absence, myoclonic, and atonic seizures also fall in this group.

Some focal seizures spread and become generalized. Witnesses are often the best source of information here, because the person having the seizure may remember very little. If you see a seizure, try to note how long it lasted, what the body did, and how the person acted afterward.

Quick Overview: 10 Causes of Seizures in Adults

The table below summarizes the causes of seizures in adults that we discuss in detail in the next sections.

1. Epilepsy as one of the Leading Causes of Seizures in Adults

Epilepsy is the first condition most people think of when they hear about the causes of seizures in adults. It can begin in childhood, but it can also begin for the first time in a person’s 30s, 50s, or 70s. In fact, new epilepsy becomes more common again in older adults, largely because of the other conditions on this list.

In some people, epilepsy is genetic. In many adults, it develops after a brain injury, stroke, infection, or tumor. In a sizeable group of patients, no cause is ever found even after careful testing. That does not mean the condition is untreatable. Most adults with epilepsy gain good control with the right anti-seizure medication.

Epilepsy is a long-term condition that needs a long-term plan. Our guide to Epilepsy Management: 9 Proven Steps to Take Control of Seizures explains what that plan looks like, from medication choices to trigger tracking and follow-up visits.

2. Stroke: A Leading Cause of New Seizures After Age 60

Stroke is one of the most common causes of seizures in adults, especially in people over 60. When blood flow to part of the brain is cut off, or when a vessel bleeds, brain tissue can be damaged. The injured area may later heal with scar tissue, and that scar tissue can become a source of abnormal electrical activity.

Seizures can happen in two time frames. Early seizures occur within the first days after a stroke, often as a direct response to the injury. Late seizures can appear weeks, months, or even years later and are more likely to point to post-stroke epilepsy.

Hemorrhagic strokes, which involve bleeding in or around the brain, carry a particular risk. You can learn more about the bleeding type in our article What Causes Intracerebral Hemorrhage?, and about the clot-related type in What Causes Ischemic Stroke?

Because stroke is so often behind the causes of seizures in adults, a first seizure in an older person should prompt a careful look at the blood vessels and the brain. Our post 12 Early Ischemic Stroke Symptoms That Save Your Life lists the warning signs every adult should recognize. Dr. Chaudhry’s training as a vascular neurologist and neuro-intensivist is especially useful here, since it links seizure care to stroke care.

3. Head Injury and Traumatic Brain Injury

A blow to the head can injure the brain in many ways, including bruising, bleeding, and tearing of nerve fibers. Moderate and severe injuries carry a higher chance of later seizures, but even some milder injuries can leave behind irritated brain tissue.

Post-traumatic seizures are divided into three groups. Immediate seizures happen within the first 24 hours. Early seizures occur within the first week. Late seizures appear after a week and may signal post-traumatic epilepsy, which can emerge months or years after the injury.

Common sources of head trauma in adults include car crashes, falls, sports injuries, and workplace accidents. If you have had a head injury and notice any of the signs described in 10 Warning Signs of a Head Injury You Should Never Ignore, do not wait to be evaluated. You may also find our page on Concussion & Post-Concussion helpful if your symptoms continue after a mild injury.

4. Brain Tumors and Other Structural Lesions

Tumors, cysts, and abnormal blood vessel clusters can all irritate the surrounding brain cells and trigger seizures. For some patients, a seizure is the very first sign that a tumor exists.

Both cancerous and noncancerous growths can cause seizures. Slow-growing tumors in the temporal and frontal lobes are particularly known for it. Other structural problems include cavernous malformations, arteriovenous malformations, and scar tissue left by earlier brain surgery.

An MRI of the brain is the best test to find these lesions. This is one reason that every adult with a first unexplained seizure should have brain imaging. When a structural cause is found early, treatment of the lesion, together with seizure medication, can greatly reduce future risk. It is among the causes of seizures in adults that we most want to rule out quickly.

5. Brain Infections and Inflammation

Infections that reach the brain or its protective lining can cause seizures during the illness and sometimes long afterward. Examples include bacterial meningitis, viral encephalitis, brain abscesses, and parasitic infections such as neurocysticercosis, which is more common in some parts of the world.

An infection-related seizure is often accompanied by fever, severe headache, neck stiffness, confusion, or unusual sleepiness. This combination is a medical emergency. Prompt treatment with antibiotics or antiviral drugs can be life-saving.

Some people develop epilepsy after recovering from a brain infection, because the inflammation leaves lasting scars. This is why follow-up with a neurologist matters even when the infection itself has been cured. When doctors list the causes of seizures in adults that need urgent action, infection is always near the top.

6. Alcohol Use and Alcohol Withdrawal

Alcohol has a complicated relationship with the brain. Heavy drinking over months or years changes brain chemistry. When a heavy drinker stops suddenly, or even cuts back sharply, the brain can become overexcited, and seizures can occur within 6 to 48 hours.

Alcohol withdrawal seizures are one of the most common provoked causes of seizures in adults, and they can be dangerous. They may be followed by delirium tremens, a severe withdrawal state with confusion, fever, and a racing heart. This is why anyone who drinks heavily should not stop alone without medical advice.

Binge drinking can lower the seizure threshold in people who already have epilepsy, and alcohol can interact with seizure medications. If you are worried about your drinking, talk to a clinician about a safe, supervised plan.

7. Metabolic and Medical Imbalances

The brain depends on a steady supply of sugar, salt, oxygen, and other chemicals. When these fall out of balance, seizures can follow. Common metabolic causes of seizures in adults include:

• Very low blood sugar, especially in people who take insulin or certain diabetes medicines
• Low sodium levels, which can be triggered by some medications, heavy water intake, or illness
• Low calcium or magnesium levels
• Kidney failure, which allows waste products to build up in the blood
• Liver failure, which can cause a toxic state called hepatic encephalopathy
• Severe dehydration or heat illness

Metabolic seizures are usually fixed by correcting the underlying imbalance. That is why blood tests are one of the first steps in any seizure evaluation. If you live with diabetes, our article on Diabetic Neuropathy Symptoms: 10 Warning Signs in Feet explains how this condition can affect the nervous system in other ways too.

8. Sleep Deprivation, Stress, and Other Seizure Triggers

Sometimes a seizure happens because the brain is pushed past its limit rather than because of a clear disease. Lack of sleep is the best-known example. When you are exhausted, your brain becomes easier to tip into a seizure, particularly if you already have epilepsy or a family history.

Other common triggers include:

• Emotional or physical stress
• Fever and illness
• Missed doses of seizure medicine
• Flashing lights or patterns in people with photosensitive epilepsy
• Hormonal changes, such as those linked to the menstrual cycle
• Extreme overheating or intense exertion without enough fluids

A trigger is different from a cause. A trigger sets off a seizure in a brain that is already vulnerable. This is why a seizure diary is so useful. Writing down sleep, stress, meals, medications, and alcohol use can reveal a pattern. Our guide to Epilepsy Management: 9 Proven Steps to Take Control of Seizures explains how to start one.

9. Medications, Recreational Drugs, and Withdrawal

Many people do not realize that certain prescriptions and substances are among the causes of seizures in adults. Some drugs lower the seizure threshold, even at normal doses. Others become risky in overdose or when stopped suddenly.

Examples of medicines that can raise seizure risk in some people include certain antidepressants such as bupropion, the pain medicine tramadol, some antibiotics, and some antipsychotics. Stimulant drugs, including cocaine and amphetamines, can also trigger seizures. Abrupt withdrawal from benzodiazepines or barbiturates is another well-known cause and can be dangerous.

Never stop a medicine on your own. If you suspect a drug is involved, talk to your prescriber or pharmacist. Bring a full list of everything you take, including supplements and over-the-counter products, to your neurology visit.

10. Dementia, Neurodegenerative Disease, and Autoimmune Conditions

As the brain ages or is affected by disease, its wiring can change. Adults with Alzheimer’s disease have a higher risk of seizures than people of the same age without dementia, and the seizures are sometimes subtle, such as brief staring spells or short periods of confusion that families mistake for memory problems.

Our article Alzheimer’s Disease: 10 Early Symptoms You Should Never Ignore can help you tell the difference between normal aging and warning signs.

Autoimmune conditions are a less common but important group. In autoimmune encephalitis, the immune system mistakenly attacks brain cells, causing seizures, memory trouble, and behavior changes, sometimes rapidly. Multiple sclerosis can also be linked to seizures in a small number of patients. These causes of seizures in adults are easy to miss, which is why a thorough neurological workup matters.

What If No Cause Is Found?

In roughly a third of adults with epilepsy, testing does not reveal a clear cause. This is called cryptogenic or unknown-cause epilepsy. It can feel frustrating, but it does not change the outlook very much. Many of these patients respond well to medication.

As genetic testing and imaging improve, more hidden causes of seizures in adults are being found each year. Your neurologist may revisit your case after some time if new symptoms appear.

Seizure or Something Else? Conditions That Look Similar

Not every episode of shaking or blacking out is a seizure. Doctors must separate seizures from other conditions that mimic them, including:

• Syncope (fainting): A drop in blood flow to the brain, often with brief jerking movements. Read more in our page on Syncope & Fainting Spells.
• Heart rhythm problems: Irregular heartbeats can cause blackouts that resemble seizures.
• Psychogenic non-epileptic events: Episodes linked to psychological stress rather than abnormal electrical discharges. These are real and need proper treatment.
• Migraine with aura: Visual or sensory changes can look like a focal seizure. Our post 11 Migraine Triggers That Could Be Causing Your Headaches explains the differences.
• Sleep disorders: Some night events, such as parasomnias, can be mistaken for nighttime seizures.

Getting this right is important because the wrong label leads to the wrong treatment. Video recordings made by family members on a phone can be extremely valuable.

How Doctors Find the Causes of Seizures in Adults

When you see a neurologist after a seizure, the evaluation usually follows a clear sequence. A long description is below, because understanding the process can lower anxiety about it.

First, your doctor takes a detailed history. They ask what happened before, during, and after the event, about your medications, alcohol and drug use, sleep, head injuries, past infections, and family history. Witness accounts are especially helpful.

Next comes a physical and neurological examination, followed by blood tests to look for metabolic problems, infection, or toxins. An electrocardiogram may be done to rule out a heart rhythm cause. Brain imaging, usually MRI, looks for structural causes such as strokes, tumors, and scars. In some cases, a lumbar puncture is needed to check for infection or inflammation.

The electroencephalogram, or EEG, records the brain’s electrical activity and can show patterns that raise the risk of future seizures. You can learn what to expect in our article Electroencephalogram (EEG) Testing: 7 Critical Facts. If a stroke is suspected, further tests described in Stroke Etiology Testing: 6 Critical Tests That Reveal What Caused Your Stroke may be added.

For a broader background on how seizure causes are grouped, the National Institute of Neurological Disorders and Stroke offers a reliable overview, and Healthline summarizes common first-time seizure causes in plain language.

Treatment: What Happens Once the Cause Is Known

Treatment depends on the cause. When the trigger is temporary and treatable, the plan is usually to fix the trigger. Examples include correcting low sodium, treating an infection, adjusting a medication, or supervising alcohol withdrawal.

When epilepsy is diagnosed, daily anti-seizure medication is the usual first step. According to the Epilepsy Foundation, about 60 to 70 percent of people can control their seizures well with medication alone. If two well-chosen medicines do not work, doctors consider advanced options, including vagus nerve stimulation, responsive neurostimulation, dietary therapy, and surgery for carefully selected patients.

If a tumor, bleed, or other structural problem is behind the seizure, treating that problem is part of the plan. For stroke survivors, controlling blood pressure, cholesterol, and heart rhythm lowers the risk of another stroke and of further seizures. Our article on Stroke: Evaluation and Treatment, 9 Critical Steps That Save Lives covers that process, and 10 Recovery Tips to Avoid Post-Stroke Complications explains life after discharge.

For a clear, current explanation of adult-onset epilepsy and its common causes, Medical News Today is another useful external resource.

Seizure First Aid: What to Do and What to Avoid

Anyone can learn to help during a seizure. Stay calm and keep these steps in mind.

• Note the time the seizure begins.
• Move hard or sharp objects away from the person.
• Gently help them to the floor and cushion their head.
• Turn them onto their side once the shaking stops.
• Loosen anything tight around the neck.
• Stay with them until they are fully awake.

Never hold the person down. Never put anything in their mouth. Do not give food, drink, or pills until they are fully alert.

Call 911 if the seizure lasts longer than five minutes, if another seizure follows right away, if the person has trouble breathing or does not wake up, if it happens in water, if the person is injured or pregnant, or if it is their first seizure. A first seizure always deserves a medical evaluation, even if the person seems to recover fully.

When to See a Neurologist

You should see a neurologist after any seizure, including one that seems minor. Make an appointment promptly if you notice any of the following:

• A first seizure at any age
• Seizures that are becoming more frequent or more severe
• Brief staring spells, unexplained confusion, or unusual sensations that repeat
• Seizures that follow a stroke, head injury, or brain infection
• Side effects from seizure medicine that interfere with daily life

Our article When to See a Neurologist: Occasional Symptoms vs. Symptoms That Need Attention and Neurology Consultation: 15 Signs to Make an Appointment at Consultant Corner in Bloomington, IL and El Paso, TX can help you decide. To see the wider range of problems our team treats, read 24 Neurological Conditions Treated by Consultant Corner in Bloomington, IL & El Paso, TX.

Living Well and Lowering Your Risk

You cannot prevent every one of the causes of seizures in adults, but you can lower your risk and reduce the chance of triggers. Here are practical steps that make a real difference:

Protect your brain from injury by wearing a seatbelt and helmet and by reducing fall hazards at home. Keep blood pressure, cholesterol, and blood sugar under control to reduce stroke risk. Limit alcohol, and never stop heavy drinking abruptly without medical help. Maintain regular sleep habits and manage stress. Take medicines exactly as prescribed, and ask before adding new ones. Treat infections promptly, and keep vaccinations up to date.

Many patients find these habits are easier to keep when they are part of a bigger brain-health routine. See our posts 9 Habits That Reduce Headaches and Support Brain Health and Early Brain Health Care Can Save Lives: 12 Warning Signs for ideas that apply to everyone.

Also remember the emotional side. Anxiety, low mood, and worry about when the next seizure might happen are common after a first event. Tell your care team about them, because good seizure care includes mental health and quality of life, not just a seizure count.

Our Collaboration with MyCare Express Care in Bloomington, IL

Consultant Corner is proud to collaborate with MyCare Express Care, a walk-in clinic at 1404 Eastland Drive, Suite 103, Bloomington, IL 61701. MyCare Express Care provides care for non-emergency illnesses and injuries, including headaches, minor trauma, concussions, and X-ray services. The clinic also offers wellness services and now offers virtual neurology appointments, which give Bloomington-area patients another convenient route to neurological follow-up.

The clinic accepts many insurance plans and welcomes self-pay patients. Its DirectCare option offers clear pricing without insurance, which can ease the cost worry that so many families feel during testing and follow-up. The clinic is open Monday to Friday from 7 am to 7 pm and on weekends from 10 am to 4 pm, and you can call 309-319-2393.

Please remember that MyCare Express Care is a walk-in clinic and not an emergency room. If someone is having a seizure that lasts more than five minutes, call 911.

How Consultant Corner Helps Patients Understand the Causes of Seizures in Adults

At Consultant Corner, we believe a seizure should never be left unexplained. Our care includes:

• A complete neurological assessment, including seizure history, medication review, and witness accounts
• EEG and imaging coordination to look for structural and electrical causes
• Personalized medication management with attention to side effects
• Stroke and brain injury follow-up for patients at risk of later seizures
• Trigger, sleep, and lifestyle counseling
• Ongoing follow-up that tracks seizures, mood, memory, and quality of life

Dr. Chaudhry’s background in vascular neurology and neurocritical care means patients with stroke, bleeding, or brain injury receive integrated care rather than a one-size-fits-all approach. You can also learn why patients choose us in Neurological Care: 10 Reasons Patients Choose Consultant Corner in Bloomington, IL & El Paso, TX and explore our Neurological Care in Bloomington, Expert Brain Health Services page.

Frequently Asked Questions About the Causes of Seizures in Adults

1. What are the most common causes of seizures in adults?

The most common causes of seizures in adults include epilepsy, stroke, head injury, brain tumors, infections, alcohol withdrawal, metabolic imbalances, and certain medications. In adults over 60, stroke and dementia-related brain changes are especially common.

2. Can a seizure happen once and never again?

Yes. A single seizure caused by a temporary problem, such as low blood sugar, dehydration, or alcohol withdrawal, may never return once the trigger is treated. Your neurologist will decide whether you are at risk of more.

3. Does having a seizure mean I have epilepsy?

Not necessarily. Epilepsy is usually diagnosed after two or more unprovoked seizures, or after one seizure with a high risk of another based on testing.

4. Can stress alone cause a seizure?

Stress by itself is rarely the only cause, but it can trigger a seizure in a person who already has a lowered threshold, especially when combined with poor sleep.

5. Can lack of sleep cause seizures in adults?

Severe or chronic sleep loss can trigger seizures, particularly in people with epilepsy or a family history. Regular sleep is one of the simplest protective steps.

6. Can seizures begin for the first time in old age?

Yes. New seizures are common after age 60, often because of stroke, dementia, or brain injury. Any new seizure in an older adult deserves a complete workup.

7. What tests are used to find the cause of a seizure?

Common tests include blood work, brain MRI, EEG, an electrocardiogram, and sometimes a lumbar puncture. The exact set depends on your history and symptoms.

8. Can medications cause seizures?

Yes. Some antidepressants, pain relievers, antibiotics, and other drugs can lower the seizure threshold, and stopping some medicines abruptly can also cause seizures. Always speak with your prescriber before changing a dose.

9. Should I go to the emergency room after a first seizure?

Yes, in most cases. A first seizure, a seizure longer than five minutes, repeated seizures, trouble breathing, injury, or a seizure in water all call for emergency care.

10. Can seizures be controlled?

Often, yes. Most adults with epilepsy achieve good control with medication, and seizures caused by treatable triggers can be prevented by correcting the cause.

Talk to a Neurologist About the Causes of Seizures in Adults

Understanding why a seizure happened is the first step toward preventing the next one. Whether you have had one episode or many, our neurology team can help you find answers and build a plan that fits your life.

To schedule a consultation, contact Consultant Corner online, or book your appointment now. You can also call +1 888 208 2208 or email info@myconsultantcorner.com. We see patients in Bloomington, Illinois and El Paso, Texas.