The Most Common Risk Factors and Triggers of Seizures

Seizures happen for various reasons, but some causes are more common than others.

  • Brain cells communicate through chemical and electrical signals. When the electrical signal becomes uncontrolled and abnormal, it results in a seizure.
  • Seizures are most commonly associated with epilepsy, but many things can cause seizures, such as brain injuries, drug abuse, heart disease, and hypertension.
  • If you have repeated seizures, you may be able to figure out your seizure triggers and come up with a treatment plan with your healthcare provider.

Every minute of every day, your brain is hard at work communicating between cells. Your brain controls everything from how quickly you scroll through this article to how many times you'll blink while reading it. But sometimes, a communication breakdown or seizure causes disruption between the cells.

Here's what to know about what causes seizures, including why someone might experience one for the first time in adulthood.

Doctor explaining brain model to patient

PonyWang/Getty Images

How the Brain Communicates

The brain can control all of its voluntary and involuntary daily actions through the work of its nerve cells or neurons. By some estimates, the brain is made up of 100 billion neurons.

Those neurons constantly communicate through chemical signals called neurotransmitters that trigger electrical activity in the brain. Those neurotransmitters can make cells more active, or they can dampen a cell's activity.

When the brain is functioning properly, those neurons communicate quickly and effectively, but sometimes, neurons don't fire as they should, and communication between brain cells is interrupted. That's when a seizure happens.

What Causes Seizures? Active human brain from above
Getty Images

What Causes Seizures?

At the most basic level, a seizure is caused by a burst of uncontrolled, abnormal electrical activity in the brain between neurons. As many as one in 10 people will experience a seizure in their lifetime.


Most commonly, seizures are linked to epilepsy, a brain disorder in which a person has repeated seizures over time. Technically speaking, you may be diagnosed with epilepsy if you have two unprovoked seizures (or one unprovoked seizure with the likelihood of another). A known condition does not cause seizures linked to epilepsy—hence the word "unprovoked."

"Epilepsy means that just the ups and downs of normal life will occasionally tip somebody into having a seizure; that their threshold for seizures is lower," Vikram Rao, MD, Ph.D., an associate professor of neurology at the University of California, San Francisco, told Health.

Other Common Causes

There are quite a few things that can cause seizures. Mainly, those causes are due to some sort of injury or illness that affects the brain. "Any brain can make a seizure under the right circumstances," said Dr. Rao. Beyond epilepsy, the most common causes of seizures include:

  • Abnormal levels of sodium or glucose in the blood
  • Brain infections (meningitis, encephalitis, etc.)
  • Brain injury in infants during labor
  • Congenital birth defects
  • Brain tumor
  • Drug abuse
  • Electric shock
  • Fever
  • Head injury
  • Heart disease
  • Heat illness
  • Phenylketonuria
  • Poisoning
  • Stroke
  • Pre-eclampsia
  • Liver or kidney failure
  • Malignant hypertension
  • Venomous bites and stings
  • Alcohol or drug withdrawal

If the cause is unknown, a seizure is called an idiopathic seizure, which typically occurs in children and young adults but can happen at any age. Adults with an unprovoked first seizure are at the greatest risk of experiencing another in the first two years following the initial seizure. That risk continues to decrease as the years go on.

Who Is at Risk for Having Seizures?

Many risk factors for seizures are related to brain injury or trauma. Seizure can happen to anyone, but any of the following may increase your risk of having a seizure:

  • Born underweight
  • Abnormal areas of the brain
  • Abnormal blood vessels in the brain
  • Traumatic brain injury or loss of oxygen to the brain
  • Brain tumors
  • Brain infection
  • Stroke
  • Cerebral palsy
  • Developmental or cognitive disabilities
  • Family history of seizures
  • Alzheimer's
  • Autism spectrum disorder
  • Long fever-related seizures
  • Use of illegal drugs

A national survey done by the Centers for Disease Control and Prevention and the National Center for Health Statistics of over 14,000 adults aged 20 to 80 from 2013 to 2018 found three factors that stood out in increasing the risk for epilepsy. Those aged 40 to 59 had almost a doubled risk, people who were unmarried had nearly a tripled risk, and those with a sleep disorder had a slightly increased risk.

What Can Trigger Seizures?

People who have had seizures in the past may find that those seizures are more likely to occur in certain situations, known as seizure triggers. Those triggers most commonly include:

  • Specific time of day (upon waking up or while sleeping)
  • Sleep deprivation
  • Illnesses
  • Flashing lights or patterns
  • Alcohol
  • Drug use
  • Hormonal changes
  • Dietary changes (dehydration, vitamin deficiencies, etc.)
  • Specific foods, like caffeine
  • Certain medications
  • Missed medications

These triggers can be very specific for some people, known as "reflex epilepsy." That's when seizures occur consistently in reaction to a certain stimulus (think: photosensitive epilepsy, when seizures are triggered by flashing lights).

Can Seizures Be Prevented?

As of 2022, seizures cannot be prevented with medicine or other therapies. Certain risk factors can be reduced, such as preventing brain injuries, controlling heart disease, getting quality sleep, and preventing or treating brain infections early.

What Can You Do To Reduce Your Risk of Seizures?

If your seizure trigger or triggers are known, you can reduce the reoccurrence of seizures by avoiding them. Sometimes, however, it can be difficult to know what triggers seizures, which is why healthcare providers often suggest keeping a "seizure diary" to help track seizures. You can note when a seizure occurs, whether any special situations surround it, and how you felt before and after the seizure.

Once you've verified a suspected trigger, you can also note the occurrence in your diary—even if it didn't result in a seizure. This can help you and your healthcare provider determine the trigger or triggers to refine your treatment plan and reduce their effects.

Was this page helpful?
Sources uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institute of Neurological Disorders and Stroke. Brain Basics.

  2. World Health Organization. Epilepsy.

  3. Epilepsy Foundation. What Are the Risk Factors of Seizures?

  4. Herculano-Houzel S. The remarkable, yet not extraordinary, human brain as a scaled-up primate brain and its associated costProc Natl Acad Sci USA. 2012;109(supplement_1):10661-10668. doi:10.1073/pnas.1201895109

  5. MedlinePlus. Seizures.

  6. Huff JS, Murr N. Seizure. In: StatPearls. StatPearls Publishing; 2022.

  7. Krumholz A, Wiebe S, Gronseth GS, et al. Evidence-based guideline: Management of an unprovoked first seizure in adults: report of the guideline development subcommittee of the american academy of neurology and the american epilepsy societyNeurology. 2015;84(16):1705-1713. doi:10.1212/WNL.0000000000001487

  8. Yang L, Wang Y, Chen X, et al. Risk factors for epilepsy: a national cross-sectional study from national health and nutrition examination survey 2013 to 2018IJGM. 2021; 14:4405-4411. doi:10.2147/IJGM.S323209

  9. National Institute of Neurological Disorders and Stroke. The Epilepsies and Seizures: Hope Through Research.

  10. Okudan ZV, Özkara Ç. Reflex epilepsy: triggers and management strategies. Neuropsychiatr Dis Treat. 2018; 14:327-337. doi:10.2147/NDT.S107669.

  11. Epilepsy Foundation. Using Seizure Diaries.

Related Articles