BY THOMAS R. COLLINS
NEW ORLEANS—The standardized mortality rate (SMR) for patients with psychogenic non-epileptic seizures (PNES) is 2.5 times that of the general population and similar to most patients with epilepsy, according to a retrospective cohort study covering 20 years at two tertiary hospital video electroencephalography (EEG) monitoring units in Melbourne, Australia.
The findings, presented here at the American Epilepsy Society annual meeting, shed light on the seriousness of a disorder that is considered understudied and subject to stigma.
When researchers excluded patients with a known brain tumor at the time of EEG and with a malignant neoplasm listed as their cause of death, there was no significant difference between the PNES patients and the epilepsy patients.
"We expected mortality in PNES to be much higher than the general population and this was the case, with PNES patients dying at a rate more than 2.5 times greater," said presenter Russell Nightscales, a medical student at the University of Melbourne. "But given that the mortality rate is so high in epilepsy centers with high rates of treatment-refractory epilepsy, we were surprised to discover that mortality in PNES was comparable to [the rate] in those with epilepsy."
Researchers calculated mortality rates for the 5,419 patients who underwent video EEG between 1995 and 2015, extracting clinical data from records, and linking to the Australian National Death Index for mortality and cause-of-death data. About 3,400 met inclusion criteria for the study.
The relative risk of mortality for those with PNES between ages 30 and 39 was more than seven times greater than that in the general population and remained significantly elevated above the general population until age 70, Nightscales said.
The proportion of patients with PNES who died from suicide was more than four times higher than in the general population, researchers found. Most of these deaths were in younger patients, with suicides and accidental poisonings accounting for almost half of all deaths in those younger than 50.
"The high incidence of preventable deaths in those with PNES was striking," Nightscales said. "These findings are clinically important as we may be looking at a subgroup of patients that require more follow-up or more wary management to avoid these deaths."
Nightscales said he hopes that the findings help bring more research attention to PNES and that the medical community more consistently regards it as a serious disorder.
"A diagnosis of PNES is often communicated to patients as being somewhat positive by way of exclusion of epilepsy," he said. "We can now conclude that this is not the case. We hope that our research is a major step in deconstructing these misconceptions. Showing the medical and general communities that this is an important diagnosis with serious implications is a key feature of our research."
Selim Benbadis, MD, FAAN, professor of neurology at the University of South Florida, said he at first thought the findings were surprising, but upon more reflection realized the high mortality rate in PNES makes sense.
"Not only do these patients have a mental disorder, but it's [often also] undiagnosed for years," Dr. Benbadis said. "They have other unexplained symptoms. Because they have multiple unexplained symptoms, once they are diagnosed with psychogenic seizures, they may not be taken seriously. People tend to dismiss everything as psychogenic, perhaps." This, he said, could delay care.
Patients with PNES need more care than they tend to get, including screening for depression, and that care can be hard to come by.
"Once diagnosed, they need to have serious treatment — that means psychiatric medication and psychological therapy. Getting mental health professionals interested in this is a challenge, as it has always been."
Nightscales and Dr. Benbadis reported no disclosures related to the study.
LINK UP FOR RELATED INFORMATION
AES Abstract 1.139: O'Brien TJ, Nightscales R, McCartney L, et al. Mortality in patients with psychogenic non-epileptic seizures.