Veterans with epilepsy or conversion disorder have increased risk of suicide-related behaviors

BY ERIK GREB

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Veterans with epilepsy or conversion disorder are at higher risk for death by suicide, suicide attempt, and suicidal ideation than those with other chronic disorders, according to an analysis presented at the annual meeting of the American Epilepsy Society. Furthermore, veterans with conversion disorder may have a greater risk of suicide attempt and suicidal ideation than do veterans with epilepsy, but they may be equally or less likely to die by suicide than the latter group.

More than 6,000 veterans or military service members die of suicide-related causes each year. Previous investigations indicated that people with seizure disorders have an increased risk of suicide. Suicide and seizures share several risk factors, such as mental health comorbidities and traumatic brain injury. These risk factors are highly prevalent among veterans, who thus may be at risk of suicide and seizures. Estimates of the risk of suicide death in veterans with epilepsy or conversion disorder have not been published, however.

Investigators retrospectively reviewed veterans’ health data

To estimate this risk, Marissa A. Kellogg, MD, assistant professor of neurology at Oregon Health and Science University in Portland, and colleagues retrospectively reviewed anonymized data from the Veterans Affairs Corporate Data Warehouse. Using ICD-9 codes, the researchers identified all veterans treated in the VA system during 2006-2015 for epilepsy, conversion disorder, depression, substance use disorder, PTSD, Parkinson’s disease, multiple sclerosis, and other chronic illnesses such as diabetes. In this population, which included millions of veterans, Dr. Kellogg and colleagues identified all patients with each chronic condition who had received a diagnosis of suicide-related behaviors, including suicidal ideation, suicide attempt, and presumed death by suicide. Next, they calculated the unadjusted proportions of veterans with each diagnosis who had each outcome and, using these proportions, calculated odds ratios. The investigators selected hypertension as the comparator condition.

Dr. Marissa A. Kellogg

Veterans with epilepsy or conversion disorder had significantly higher unadjusted odds of reported suicide-related behaviors, compared with veterans with all other comparator medical, neurologic, and psychological disorders examined. The odds ratios for presumed suicide death, suicide attempt, and suicidal ideation in epilepsy were 4.6, 5.0, and 4.5, respectively. The corresponding odds ratios were 3.6, 6.8, and 6.7, respectively, among patients with conversion disorder. In comparison, the odds ratios for presumed suicide death, suicide attempt, and suicidal ideation were 2.6, 3.0, and 3.3, respectively, in patients with depression; 2.1, 2.5, and 2.5, respectively, in patients with substance use disorder; 2.3, 3.4, and 3.7, respectively, in patients with PTSD; 1.3, 1.6, and 1.6, respectively, in patients with multiple sclerosis; and 1.01, 1.26, and 1.29, respectively, in patients with Parkinson’s disease. Among the chronic medical illnesses examined, the highest odds ratios for suicide-related behavior were among veterans with asthma (1.5, 2.0, and 2.0, respectively). The risks of suicide attempt and suicidal ideation were significantly higher in veterans with conversion disorder than those with epilepsy. The risk of presumed suicide death, however, was not higher in patients with conversion disorder.

Screening for suicide-related behaviors may be advisable

Because the investigators identified patients with conversion disorder using ICD codes, it is unclear how conversion disorder manifested itself in any given patient. “ICD codes are not always specific, and different providers use different codes for the same diagnosis,” said Dr. Kellogg. “The sample was not exclusively patients with psychogenic nonepileptic seizures [PNES], and we don’t know what the percentage would have been. This would be an important area for future research.

“We should be screening for suicide-related behaviors in all our patients with epilepsy and conversion disorders, including PNES, and helping them access mental health treatment,” she continued. “Our patients with epilepsy and PNES are at higher risk for suicidal ideation, suicide attempts, and suicide deaths. This [finding] has been previously reported in the civilian literature, and these data support it in U.S. veterans.”

The study was funded by the National Institutes of Health. The investigators reported no conflicts of interest.