Psychogenic Seizures Tied to Sexual Assault, Stroke

Pauline Anderson

December 15, 2020

Individuals who have experienced sexual trauma have more than a tenfold increased risk of developing psychogenic nonepileptic seizures (PNESs) and are also more likely to suffer a stroke, new research shows.

"These patients are experiencing a pretty significant burden of health conditions that go beyond just the PNES diagnosis," study investigator Lea Davis, PhD, associate professor, Division of Genetic Medicine, Vanderbilt University, Nashville, Tennessee, told Medscape Medical News.

"As a biomedical research community and a medical practice community, we need to start understanding the whole picture of everything that's affecting these patients, from both the psychiatric and the more traditional physical/medical perspectives," she said.

The findings were presented at the American Epilepsy Society (AES) 74th Annual Meeting 2020, which was held online this year because of the COVID-19 pandemic.

Misdiagnosis Common

PNESs can resemble epileptic seizures in that they can involve convulsions and periods of unresponsiveness. However, with PNES, the aberrant electrical brain signal seen on electroencephalogram (EEG) is not present.

PNES onset is thought to be primarily related to emotional stress, but up to 80% of patients with the condition are initially misdiagnosed with epilepsy. Complicating the diagnosis is the fact that there is currently no International Classification of Diseases code for the disorder.

To identify patients who have PNES, researchers searched Vanderbilt's electronic health record (EHR) system using an automated phenotyping algorithm that incorporates diagnostic codes and natural language processing. From 2,346,808 records, they identified 3341 adult patients with PNES, a prevalence rate of 0.14%.

This rate is higher than previously thought, said study investigator Slavina Goleva, a PhD candidate at Vanderbilt Medical Center. However, she noted that the higher rate might reflect the fact that Vanderbilt is an academic referral center with a large epilepsy-monitoring unit.

About 74% of the patients with PNES were women, said Davis. She noted that sexual assault trauma is more common among women than men.

The researchers determined that sexual assault trauma accounted for about a quarter of the male/female imbalance in PNES. "Sexual assault trauma is not the only reason for PNES, but it appears to be one of the major contributors," said Davis.

PNES is a "form of conversion and dissociative disorder," said Haas. A history of traumatic events is one of the major risk factors for developing dissociative disorder.

Robust Tie to Sexual Trauma

The researchers determined which of 1653 medical diagnoses in the university's EHR system co-occurred with a PNES diagnosis after accounting for key clinical and demographic covariates, such as sex, age, body mass index, and race.

They found a robust association between sexual assault trauma and PNES. Patients who had experienced such trauma were more than 10 times more likely to have PNES (odds ratio [OR] 10.26; P = 5.36 × 10-146), which Goleva noted is "an incredibly small P value and much less than 0.05."

"It was striking to us how strong that association was in our data," added Davis.

As with previous research, the current study showed an association between PNES and psychiatric disorders. About 30% of the PNES patients in the study had major depression or anxiety.

In addition, compared to the general population, PNES patients are 15 times more likely to have posttraumatic stress disorder. Davis noted that her group is collaborating with a veterans program in which the EHR system is "enriched" with men.

They are interested in learning whether war trauma has the same relationship with PNES as sexual assault trauma, she said.

The mechanism underlying the relationship between trauma and seizures is unclear. One hypothesis is that such seizures are a neurologic consequence of trauma in some people, said Davis.

Link to Stroke

Interestingly, the study also identified an association between PNES and cerebrovascular disease (OR, 1.08; P = 2.57 × 10-40).

This "novel co-occurrence" between PNES and stroke "is definitely statistically significant," and although the basis of the relationship is unclear, it could be due to a shared common risk factor, said Davis.

"We want to invite people to dig into this potential relationship so we can understand it better," she added.

The researchers recommend that clinicians refer stroke patients who experience seizures for video EEG evaluation.

One of the strongest messages coming out of this new research, said Davis, is that PNES is not strictly a psychiatric disorder, nor is it strictly a neurologic disorder. "It's actually something that affects patients top to bottom and throughout their lifetime and requires more comprehensive care," she said.

To date, there is no approved medication for PNES. However, cognitive-behavioral therapy is a promising treatment, said Goleva.

Even if PNES patients are referred to a psychologist or psychiatrist, "we continue to follow them in the neurology clinic as well," said Haas. He emphasized the importance of a multidisciplinary approach "to get patients down the right treatment path."

Novel Finding

Commenting on the study for Medscape Medical News, neurologist and epilepsy specialist Terence J O'Brien, MD, Department of Neuroscience, Central Clinical School, and Monash University, Melbourne, Australia, said the study "is very important" despite the limitation of being a retrospective review.

"This is a very underresearched area, so any new data are welcome," he said.

The link between sexual trauma and PNES is not surprising, because other studies, including his own, have reported the same association, said O'Brian. "But it's good to have some more data confirming that association," he said. He noted that the "more we know about this disabling condition the better."

He added that the finding that PNES is associated with stroke is novel. "I haven't seen that reported before," he said.

He speculated that this link might have something to do with socioeconomic status (SES). His research team and others have tied low SES to increased PNES risk, possibly because those who are disadvantaged are more likely to experience early-life trauma.

In addition, groups with lower SES tend to have lifestyle factors ― smoking, obesity, and less access to healthcare ― that put them at increased risk for stroke.

O'Brian agreed that the best approach to PNES is an accurate diagnosis so patients aren't erroneously treated for epilepsy.

As it stands, it's "very, very common" that patients with PNES are misdiagnosed with epilepsy "for years" and are treated with antiepileptic medications, he noted.

The study received funding from the National Institutes of Health and National Science Foundation.

American Epilepsy Society (AES) 74th Annual Meeting 2020: Abstract 912514 (poster 407). Presented December 6, 2020.

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