Epilepsy or Not? PNES Mistaken for More Common Seizure Disorder

When someone collapses to the floor, back arching, arms and legs thrashing, your first thought may be epileptic seizure.

And you wouldn’t be alone—until recently, most doctors thought the same thing. During an epileptic seizure, the brain, which normally operates in an orderly way by sending electrical messages from neuron to neuron, becomes overloaded. If a healthy brain functions like a well-conducted orchestra, with each instrument playing its part at the right time, a brain during an epileptic seizure functions more like a chaotic musical mishmash, where every instrument plays at once, without regard for any of the others around it. Seizures caused by epilepsy overwhelm the brain with electronic messages, which is what causes the person to move uncontrollably or to see, hear, and feel things they normally wouldn’t.

But recent research suggests that about 10 percent of patients previously diagnosed with epilepsy don’t have epilepsy at all. These patients are actually having a different kind of seizure known as a “psychogenic non-epileptic seizure” or PNES. These seizures can look and feel the same as epileptic seizures, but people with PNES are not experiencing the same electrical overload in their brains. For this reason, traditional epilepsy treatments, such as anti-seizure medications, don’t work and can even introduce harmful side effects for these patients. In extreme cases, patients with PNES, who have not been helped by medications, have undergone unnecessary surgery in an attempt at a cure. But the problem is, seizures are not caused by an abnormality in the brain (the way they are with epilepsy).

So, what causes non-epileptic seizures? Current research suggests that psychogenic non-epileptic seizures can be triggered by post-traumatic stress disorder (PTSD) or other abnormally high levels of stress. But the exact mechanism that leads to this type of seizure is unknown.

“We think it’s like having a really extreme stress response,” says Benjamin Tolchin, MD, MS, a neurologist at Yale Medicine. Earlier this year, Dr. Tolchin published a study in the journal Neurology that looked at the effectiveness of psychotherapy on patients with psychogenic non-epileptic seizures.

In the study, 105 people diagnosed with PNES were referred to receive psychotherapy. After 12 to 24 months had passed, Dr. Tolchin and his research team called participants to follow up. Those who attended at least eight sessions within a 16-week period saw a reduction in seizure frequency, an improvement in quality of life, and a decrease in emergency room visits.

“Our study suggests that psychotherapy is helpful for patients with PNES, and that in order to gain the full benefit, patients must fully engage with and adhere to the complete psychotherapy regimen,” says Dr. Tolchin. He’s personally seen the dramatic effects of therapy on many of his own patients—some no longer have any seizures at all.

The difficult part is identifying which patients with seizures have PNES and which have epilepsy, since the seizures caused by both conditions look and feel similar. In fact, a small group of patients have both epileptic seizures and psychogenic non-epileptic seizures, and sometimes cannot tell the difference between the two. Most of the time, PNES is diagnosed when a patient has been having seizures that aren’t helped by traditional epilepsy medications. The patient is then referred to a seizure specialist who, in a controlled clinic environment, obtains a video-electroencephalogram (EEG) to measure the electrical activity of the patient’s brain during multiple seizures over a span of a couple of days. (Patients who have epilepsy will often show characteristic spikes in electrical activity on the EEG, while patients who have PNES will show normal brain activity.)

While doctors have been describing psychogenic non-epileptic seizures for centuries, a definitive diagnosis has only been possible since the advent of the video-EEG. Even now, however, PNES often goes underdiagnosed and undertreated because many doctors are unfamiliar with it. Dr. Tolchin hopes to change that by establishing national guidelines for diagnosing and treating patients with PNES.

“There is increasing awareness of PNES, but it is not as good as it should be,” he says. PNES might be the problem for patients who have not responded to epilepsy medications. For such patients, Dr. Tolchin suggests requesting a referral to a specialty epilepsy center, like the Epilepsy and Seizures Program at Yale Medicine.

Specialist attention can be helpful in all cases, because even among epilepsy patients, there are several different variations and types of seizures. For instance, there are focal onset seizures, which affect a small part of the brain, and generalized onset seizures, which affect broader parts of the brain. Differentiating between the two is important because there are different medications for each. Even within those broad categories, people can have different types of seizures: Some can cause a person to lose consciousness while others only affect a person’s muscles but do not impact a person’s ability to think.

Women with epilepsy also have to take extra care. Research suggests that elevated estrogen and progesterone ratios (which happens around ovulation) can increase risk for seizures. In addition, pregnant women with generalized tonic-clonic seizures (the type of seizure that involves the entire brain and causes a total loss of consciousness) should be aware that these seizures can be harmful to her and her fetus. Moreover, certain epilepsy medications should be avoided because they can increase the risk for birth defects. However, women with epilepsy can safely become pregnant, give birth to a healthy baby, and breast feed, if they are under the care of an epilepsy specialist to ensure the safety of the mother and baby.

As for Dr. Tolchin, he’s continuing his research on the many types of epileptic seizures and on psychogenic seizures. “These are complex and debilitating disorders,” says Dr. Tolchin. “But we’re advancing knowledge and care for our patients every day.” 

Click here to learn more about Yale Medicine's Epilepsy & Seizures Program.