FND seizures are episodes that look and feel like epileptic seizures but are not caused by abnormal electrical activity in the brain. They fall under functional neurological disorder (FND), a condition where the nervous system sends and receives signals incorrectly, producing real physical symptoms without a structural or electrical cause. These seizures affect a significant number of people: 20% to 30% of patients referred to epilepsy monitoring units turn out to have functional seizures rather than epilepsy.
Why the Name Keeps Changing
If you’ve searched for this topic before, you may have encountered a confusing list of terms. These seizures have been called psychogenic nonepileptic seizures (PNES), pseudoseizures, conversion seizures, dissociative seizures, nonepileptic attack disorder, and several other names. The International League Against Epilepsy now recommends the term “functional/dissociative seizures” (FDS), giving clinicians flexibility to use either word depending on the patient and context.
The shift away from older terms happened for good reasons. “Psychogenic” implied the problem was purely psychological, which felt dismissive to many patients and didn’t reflect the neuroscience. “Nonepileptic” only described what the seizures weren’t. “Pseudoseizure” suggested the episodes were fake, which they are not. The newer terminology acknowledges that these are real neurological events with a different mechanism than epilepsy.
What Happens in the Brain
Functional seizures arise from disrupted communication between brain circuits rather than from the electrical misfires that cause epilepsy. Research has identified at least five brain functions that work differently in people with FND: emotion processing, the sense of agency (feeling in control of your own body), attention, internal body awareness, and the brain’s prediction system for incoming signals.
In practical terms, the brain’s emotional and threat-detection circuits become overly connected to its movement-control areas. The strength of this abnormal connectivity actually correlates with how severe a person’s symptoms are. At the same time, the part of the brain responsible for matching intended movements with actual movements (located at the junction of the temporal and parietal lobes) doesn’t function properly. This helps explain why patients genuinely feel they have no control over what’s happening during an episode. The seizure is involuntary, even though it doesn’t show up as abnormal electrical activity on a brain scan.
There’s also heightened activity in deeper brain structures involved in arousal and defensive responses, which may explain why seizures often occur during or after periods of stress or emotional intensity.
What FND Seizures Look Like
Functional seizures can closely mimic epileptic seizures, which is why misdiagnosis is common. However, certain features appear more frequently in functional seizures:
- Eyes closed during the episode. People with epileptic seizures typically have their eyes open.
- Out-of-sync limb movements. Arms and legs may move in alternating or irregular patterns rather than the rhythmic, synchronized jerking typical of epilepsy.
- Longer duration. Full-body shaking that lasts more than 10 minutes is more characteristic of functional seizures. Most epileptic seizures resolve within one to three minutes.
- Pelvic thrusting or rapid side-to-side head movements.
- Retained awareness during convulsive movements. Some people remain partially conscious even while their body shakes.
- Changing movement patterns. The seizure may shift in character mid-episode, with movements waxing, waning, or changing form.
None of these signs alone confirms a diagnosis. Some people with functional seizures have episodes that look nearly identical to epilepsy, and some people have both conditions simultaneously.
Common Triggers
Functional seizures often have identifiable triggers, though not always. Stressful life events, mental health conditions like anxiety and depression, relationship difficulties, and significant physical injuries or illnesses all increase risk. In daily life, episodes can be set off by emotionally charged events, poor sleep, physical exertion, dissociation (a feeling of detachment from yourself or your surroundings), and shifts in mood. Some people notice their seizures worsen during periods of negative emotion, while others find that even positive but intense experiences can trigger an episode.
It’s worth noting that a trigger doesn’t have to be a dramatic life event. Accumulated everyday stress, chronic pain, or subtle shifts in how the body processes internal signals can all contribute. Some patients never identify a clear trigger at all.
How Doctors Confirm the Diagnosis
The gold standard for diagnosing functional seizures is video EEG monitoring. During this test, you’re admitted to a monitoring unit where cameras record your physical movements while electrodes on your scalp track your brain’s electrical activity. When a typical episode occurs, doctors can see whether the brain produces the electrical patterns associated with epilepsy. In functional seizures, the EEG shows normal or near-normal brain activity even while the body is convulsing.
This test is important because it gives both the patient and the medical team a clear, positive diagnosis rather than a process of elimination. Receiving a definitive answer is itself part of treatment, since understanding the condition is a key step toward managing it.
Treatment and Recovery
Because functional seizures don’t involve abnormal electrical activity, anti-seizure medications used for epilepsy are ineffective. If you’ve been prescribed these medications based on an earlier misdiagnosis, your doctor will typically work with you to taper off them safely.
The treatment with the strongest evidence is cognitive behavioral therapy (CBT) tailored specifically to functional seizures. In a clinical trial, patients who received up to 12 sessions of CBT saw their median monthly seizure count drop from 12 to 1.5 over six months, compared to a drop from 8 to 5 in patients who received standard medical care alone. The CBT group was also roughly three times more likely to experience three consecutive months with no seizures at all.
Therapy focuses on several practical skills: learning to recognize and interrupt the early physical and mental signals that precede a seizure, gradually re-engaging with activities you’ve been avoiding out of fear of having an episode, and identifying thought patterns and beliefs about illness that may be maintaining the cycle. Sessions typically include homework like keeping a seizure diary to spot patterns.
Long-term recovery varies. Across studies, seizure remission rates after treatment range from 25% to 45%, with these improvements achieved even in patients who had been experiencing seizures for four to eight years. One study using a specific type of exposure therapy reported an 81% remission rate. Early diagnosis and early treatment tend to produce better outcomes.
What to Do During an Episode
If you’re with someone having a seizure of any kind, the immediate safety steps are the same regardless of whether the seizure is epileptic or functional. Stay calm and stay with the person. Move nearby objects that could cause injury. If they’re lying down, gently turn them onto their side with their mouth angled toward the ground to keep the airway clear. Place something soft under their head. Loosen anything tight around the neck. Time the seizure.
Equally important is what not to do. Don’t hold the person down or try to restrain their movements. Don’t put anything in their mouth. Don’t offer food or water until they’re fully alert.
Call for emergency help if the seizure lasts longer than five minutes, if another seizure follows shortly after, if the person has difficulty breathing or waking up afterward, if they’re injured during the episode, or if it’s their first seizure ever.
Living With Functional Seizures
One of the hardest parts of this diagnosis is the stigma. Older terminology and lingering misconceptions lead some people, including some medical professionals, to assume functional seizures are faked or “all in your head.” They are neither. Brain imaging consistently shows measurable differences in how the brains of people with FND process signals, handle emotions, and control movement. The seizures are involuntary, the distress is real, and the condition responds to specific treatment.
Many people with functional seizures also deal with other FND symptoms like limb weakness, tremor, or difficulty walking, as well as co-occurring anxiety or depression. Addressing these alongside the seizures, rather than treating each symptom in isolation, tends to produce the best results. A treatment team that includes both neurology and psychology, working together, reflects the current best practice for this condition.