Mental Illness Linked to Premature Death in Epilepsy Patients

Having epilepsy may predispose someone to premature death, especially if there is comorbid depression or substance abuse, according to a study conducted in Sweden and reported online in the Lancet July 22. This finding highlights the need for clinicians to screen for psychiatric illness in patients with epilepsy.

Since everyone living in Sweden has a personal identification number that can be linked to numerous types of national registries, psychiatric epidemiologists often use data from Sweden for their studies, as did the researchers for this study, which was led by Seena Fazel, M.D., a senior clinical research fellow in the Department of Psychiatry at the University of Oxford in England.

The researchers had two goals. First, they wanted to learn how prevalent premature mortality is among epilepsy patients compared with the general population and also compared with the siblings of epilepsy patients (to account for possible familial confounding). Second, they wanted to determine the causes of premature mortality among epilepsy patients and especially the role that comorbid psychiatric illness might play.

Their subjects were all individuals born in Sweden from 1954 to 2009 who had been diagnosed with epilepsy—some 70,000 individuals. They matched each subject with up to 10 individuals from the general population who were of the same age and gender, but did not have epilepsy. They also included about 81,000 individuals who were siblings of the epilepsy subjects, but did not have epilepsy.

The researchers then determined the premature death rates for each of these three groups—that is, how many died by age 56—and then compared the premature mortality findings for the epilepsy cohort with those for the general population and the epilepsy patients’ siblings.

Approximately 6,200 of the individuals with epilepsy (9 percent) died prematurely, and their average age at death was 35. Moreover, their chances of dying so early were 11 times greater than those of the general population and of their unaffected siblings, after adjusting for sociodemographic factors. “The overall high rates of premature mortality were surprising,” Fazel told Psychiatric News.

The major causes of premature death in individuals with epilepsy were natural ones, and particularly brain tumors and diseases of the nervous system related to epilepsy.

However, 972 (16 percent) of the premature deaths were from external causes, notably nonvehicular accidents such as falls, drowning, drug poisoning, or suicide.

Depression, Substance Abuse Especially Prevalent

The researchers found as well that 75 percent of the epilepsy patients who died prematurely had comorbid psychiatric disorders, particularly depression or substance abuse, and that incidence of suicide deaths was particularly high in this group.

Specifically, individuals with epilepsy and comorbid depression were 23 times more likely to die by suicide than general population controls who had neither epilepsy nor depression. In contrast, general population controls who were depressed but without epilepsy were only 10 times more likely to die by suicide those who had neither epilepsy nor depression.

Substance abuse comorbid with epilepsy also was associated with likelihood of death by suicide, as people with both conditions were 22 times more likely to die from suicide than general population controls who had neither epilepsy nor substance abuse.

In contrast, control subjects who abused substances but did not have epilepsy were nine times more likely to die by suicide than controls who had neither epilepsy nor substance abuse.

Are Depression, Substance Abuse Being Missed?

Thus, “substance misuse in suicide mortality was at least as important as depression,” the researchers said in their report, emphasizing the substantial contribution of psychiatric morbidity to the premature deaths. Fazel suggested that “One possibility that needs further investigation is that individuals with epilepsy are not being treated effectively for their comorbid depression or substance abuse.”

Their findings have implications for psychiatrists and other physicians who treat epilepsy patients, the researchers believe.

For example, “Patients with psychiatric comorbidity in the period immediately after the first diagnosis of epilepsy represent a high-risk population that might benefit from closer monitoring, consultation with liaison psychiatry, and more intensive treatments,” they noted. Since “around a third of epilepsy subjects had a comorbid psychiatric diagnosis, and around a 10th had comorbid substance misuse,” clinicians caring for epilepsy patients should step up their liaison with psychiatric and addiction services, they suggested.

“The results from this rigorously performed well-controlled study cry out to rectify the severe underfunding of epilepsy research,” Deborah Weisbrot, M.D., an associate professor of psychiatry at Stony Brook University Medical Center and an epilepsy expert, told Psychiatric News. “This study presents another compelling argument for the need for clinicians to screen for psychiatric comorbidities in epilepsy, not only to improve patients’ quality of life, but more importantly to potentially save lives.”

The study was funded by the Wellcome Trust, Swedish Research Council, and Swedish Prison and Probation Service. ■