Absence seizures usually occur due to atypical changes in brain activity. They tend to have a genetic cause. Although more common in children, they may persist into adulthood.

Absence seizures are most common in children ages 4 to 14 but can extend into early adulthood and beyond.

Individuals may have absence seizures for years before recognizing the issue. This is because absence seizures cause brief episodes of disconnection from the surrounding environment without causing body movements. Therefore, a person may mistake them for daydreaming or not paying attention.

This article examines what causes absence seizures in adults, symptoms, and when to seek medical attention.

person rubbing their eyesShare on Pinterest
Maskot/Getty Images

Absence seizures have a formal medical definition, which is that they cause a few seconds of unawareness without substantial physical movements. They begin with erratic electrical activity throughout the brain.

Most seizures that begin during adulthood are partial seizures, which are also known as focal seizures, beginning in one area of the brain. While focal seizures do not fit the medical definition for absence seizures and are treatable with different medications, they sometimes have similar symptoms.

Experts are unsure about the exact causes of absence seizures in adulthood. They often have a genetic cause, suggesting they can become passed down through families.

However, other factors may also play a role in triggering seizures and absence seizures. These factors include the following:

Researchers have identified certain genes, particularly those affecting calcium channels and gamma-aminobutyric acid (GABA), as playing a key role. GABA is a chemical messenger, or neurotransmitter, in the brain. Specific genetic variations, or copy number variants, where small DNA segments undergo deletion, have links to absence seizures in children.

Despite these findings, the exact genetic cause and mechanisms behind these seizures remain largely unknown.

Early in life

Most individuals with absence seizures receive a diagnosis in childhood, rarely in adulthood. However, when adults receive a diagnosis, they often report having a family history of seizure disorders. This points to the possibility that these individuals have a genetic predisposition to seizures from a young age but might not have recognized their episodes as medical issues.

Absence seizures can be subtle, which can contribute to their underdiagnosis. These seizures are brief, and the individual quickly returns to their typical activities. Sometimes, people can easily mistake these events for daydreaming or inattentiveness, especially in children.

They can cause a few seconds of mild eyelid fluttering or subtle mouth movements but do not cause shaking or jerking of the body.

These seizures may remain unnoticeable until a child faces academic challenges. People may then begin to suspect these moments of “spacing out” are something more than just daydreaming, prompting further investigation.

Triggers of absence seizures include the following.

Sudden cessation of medications

If a person stops taking certain medications abruptly, it could trigger any type of seizure, especially if they already have epilepsy.

Benzodiazepines are a class of drugs that include:

Doctors may prescribe these potent medications for anxiety, insomnia, and other conditions. They work by enhancing the effect of GABA, which promotes calmness and relaxation.

Benzodiazepines alter the chemistry in the brain, and when a person takes them regularly, the body adapts to their presence. Abruptly stopping them can disrupt this balance, leading to a range of potentially serious withdrawal symptoms that could include absence seizures.

Autoimmune diseases

Autoimmune diseases could trigger absence seizures by causing the body’s immune system to attack healthy brain tissue mistakenly. The resulting inflammation then disrupts brain function, altering the delicate balance of neurotransmitters. Alternatively, it can also lead to nerve damage.

Autoimmune encephalitis, which is a rare condition in which the immune system attacks the brain, is the most likely autoimmune disorder to cause seizures.

Other autoimmune disorders also have associations with an increased risk of seizures. Still, they are far more likely to cause focal onset seizures and rarely cause absence seizures.

A 2013 paper linked the autoimmune conditions Crohn’s disease and Hashimoto’s encephalopathy with absence seizures.

There is an association between mental health conditions, such as depression and anxiety, and absence seizures.

Research shows that these psychiatric conditions and absence seizures often co-occur. Absence seizures can be a sign of epilepsy. People with depression or anxiety have a higher than average risk of co-occurring epilepsy. Additionally, those with epilepsy are more likely to face mental health challenges such as depression, anxiety, and suicidal thoughts.

Further evidence comes from an extensive analysis of over 10.5 million health records that found a link between depression and epilepsy.

Specific genes and brain pathways have a role in both absence seizures and psychiatric disorders. For instance, changes in GABA function occur in both. These neurotransmitters are important for controlling mood and seizure activity. Brain structures involved in controlling emotions and seizures might also play a role.

During an absence seizure, people may:

  • stare blankly, often with a fixed gaze, as if daydreaming
  • stop what they are doing abruptly, whether it is talking, walking, or performing a task
  • blink rapidly, chew, or twitch the lips
  • be unresponsive to verbal cues or attempts to get their attention

These seizures typically last less than 20 seconds. The person may immediately resume their activity after the seizure ends, often without any awareness that it occurred.

People need to seek medical advice if they experience any of the symptoms mentioned above. They can treat the seizure and determine what the underlying cause is.

Below are some common questions about absence seizures.

What can trigger absence seizures?

Hyperventilation can trigger absence seizures in a person who already has this condition. Furthermore, certain medications can worsen symptoms, including:

  • carbamazepine
  • phenytoin
  • gabapentin
  • vigabatrin
  • other medications with similar mechanisms of action

Triggers may also include alcohol, stress, and sleep deprivation.

How do you treat absence seizures in adults?

Anti-seizure medications can help prevent absence seizures, including:

  • ethosuximide (Zarontin)
  • lamotrigine (Lamictal)
  • valproic acid (Depakene)
  • divalproex sodium (Depakote)

What causes seizures in adults with no history?

Several factors can trigger seizures in adults with no previous history of neurological issues. They can include:

  • stroke
  • infections of the nervous system
  • trauma
  • metabolic disorders
  • brain tumors
  • structural brain abnormalities
  • medications

Do absence seizures cause brain damage?

Absence seizures do not cause brain damage. However, a seizure can sometimes continue for hours to days — this is an event known as absence status epilepticus. Even these prolonged episodes rarely cause harm.

However, absence seizures may lead to learning problems and could increase the risk of injury due to impaired consciousness.

Absence seizures are more common in children than in adults. These brief lapses in consciousness may have underlying genetic factors or health conditions such as autoimmune disease or mental health issues. In some individuals who have epilepsy, medication withdrawal, alcohol, stress, and sleep deprivation may trigger a seizure.

Recognizing the symptoms of absence seizures and knowing when to seek help are vital steps in managing this condition. With appropriate treatment, many people can manage the condition effectively.