SAN DIEGO—Post-traumatic stress disorder (PTSD) preceded a diagnosis of psychogenic nonepileptic seizures in 58% of military veterans and a diagnosis of epileptic seizures in 14% of military veterans, according to Martin Salinsky, MD. His study found that a preceding history of PTSD was the only significant psychiatric predictive factor for psychogenic seizures in this population.
“This finding is largely driven by patients with a history of TBI, and particularly by patients with a history of mild TBI,” said Dr. Salinsky. “We are beginning to see a model develop whereby the development of psychogenic seizures in veterans with mild TBI may be mediated by PTSD.” Dr. Salinsky, Director of the Epilepsy Center of Excellence at the Veterans Affairs Medical Center in Portland, Oregon, presented his results at the 66th Annual Meeting of the American Epilepsy Society.
Diagnosing Psychogenic Nonepileptic Seizures in Veterans
Dr. Salinsky’s findings are the latest in his ongoing research in veterans with psychogenic nonepileptic seizures. Previously, he and his colleagues had identified psychogenic nonepileptic seizures in 25% of veterans and in 26% of civilians who were admitted to a shared epilepsy monitoring unit. “In veterans, we saw more patients with psychogenic seizures than with epileptic seizures,” he said. “In civilians, we saw many more patients with epileptic seizures as compared to psychogenic seizures. This gives the appearance that psychogenic seizures are more common in veterans, but as a percentage of all admissions, it’s almost the same.”
Dr. Salinsky’s group also compared 50 veterans and 50 civilians who were diagnosed with psychogenic seizures and found a fivefold delay (ie, five years) in the diagnosis for veterans. Some veterans had a delay as long as 20 years before being referred for video EEG monitoring. “As a result, veterans had much more AED exposure, about four times as much as civilians,” said Dr. Salinsky.
The delay in diagnosing psychogenic seizures in veterans may occur for several reasons, Dr. Salinsky theorized. First, it may be due to a lack of epilepsy monitoring units within the VA, an issue he hopes will be corrected with the creation of the VA Epilepsy Centers of Excellence program. He also speculated that many veterans with psychogenic seizures are presenting with a history of TBI and post-traumatic seizures, and that the diagnosis is not questioned because of the well-known association of TBI and epilepsy.
The TBI Effect
Dr. Salinsky and colleagues have also taken a closer look at the severity of TBI in cases that turned out to be psychogenic seizures. The researchers found that in a majority of patients, the head injury was classified as mild, and in less than a quarter the TBI was moderate to severe. “In post-traumatic epilepsy, you would expect a majority of patients to be in the moderate to severe category,” said Dr. Salinsky. “When a veteran presents with a history of seizures following a mild TBI, the red flag should go up.”
Dr. Salinsky pointed out that most patients in this study were from the Vietnam era, before an increase in blast injuries started to occur in veterans of Iraq and Afghanistan. “We really don’t know what happens with blast injuries, particularly repeated blast injuries, and the risk of epilepsy,” he commented. “So I would take this with a grain of salt.”
Psychiatric Comorbidity and Psychogenic Seizures
Understanding the relationship between preceding psychiatric disorders and psychogenic seizures may be “an opportunity to develop more effective therapeutic approaches for the treatment of these patients,” Dr. Salinsky commented. “We were particularly interested in PTSD, because it has a strong association with psychogenic seizures and with mild military TBI.”
In his group’s retrospective study of psychiatric comorbidity in veterans with psychogenic seizures, Dr. Salinsky found a mildly greater history of psychopathology in veterans with psychogenic seizures, compared with those who had epileptic seizures. “There were more Axis I diagnoses,” he said. “And there was a trend toward a higher percentage of Axis II diagnoses.”
Dr. Salinsky observed a “large and highly significant difference” in the rate of PTSD among patients with psychogenic seizures. Otherwise, the differences between the two groups of patients were relatively small and did not reach statistical significance. “I don’t think that PTSD explains every case of psychogenic seizures within the VA system, but it does appear to be one valid mechanism,” noted Dr. Salinsky. “It’s an example of how we can use research to untie this complicated knot of how a veteran develops psychogenic seizures. Undoubtedly, there are other mechanisms.”
Salinsky M, Evrard C, Storzbach D, Pugh MJ. Psychiatric comorbidity in veterans with psychogenic seizures. Epilepsy Behav. 2012;25(3):345-349.
Salinsky M, Spencer D, Boudreau E, Ferguson F. Psychogenic nonepileptic seizures in US veterans. Neurology. 2011;77(10):945-950.