Mood Disorders And Epilepsy May Share Genetic Susceptibility

For the first time, scientists at Rutgers University-New Brunswick and Columbia University have found evidence that seizures and mood disorders such as depression may share the same genetic cause in some people with epilepsy. The finding may lead to better screening and treatment to improve patients’ quality of life.

Physicians have long suspected there is a link between epilepsy and depression.

The group studied dozens of unusual families with multiple relatives who had epilepsy, and compared the family members’ lifetime prevalence of mood disorders with that of the U.S. population.

They found an increased incidence of mood disorders in persons who suffer from a type of the condition called focal epilepsy, in which seizures begin in just one part of the brain. But mood disorders were not increased in people with generalized epilepsy, in which seizures start on both sides of the brain.

Screening Needed

Gary A. Heiman, the study’s senior author and associate professor in the Department of Genetics at Rutgers-New Brunswick, said:

“Mood disorders such as depression are under-recognized and undertreated in people with epilepsy. Clinicians need to screen for mood disorders in people with epilepsy, particularly focal epilepsy, and clinicians should treat the depression in addition to the epilepsy. That will improve patients’ quality of life.”

The results of the study support the hypothesis that people with focal epilepsy, but not generalized epilepsy, are susceptible to mood disorders such as depression.

“More research is needed to identify specific genes that raise risk for both epilepsy and mood disorders,” said Heiman. “It’s important to understand the relationship between the two different disorders.”

A relationship between epilepsy and mood disorders has been suspected for millennia, Heiman noted. Hippocrates, “the father of medicine,” wrote about it around 400 BC:

“Melancholics ordinarily become epileptics, and epileptics, melancholics: what determines the preference is the direction the malady takes; if it bears upon the body, epilepsy, if upon the intelligence, melancholy.”

Quality Of Life Issues

Seizures in most people with epilepsy can be controlled by drugs and surgery. The fact remains, however, that epilepsy and mood disorders such as depression affect quality of life and increase disability and healthcare costs.

Credit: National Institutes of Health

Depression raises the risk for suicidal thoughts and attempts. Moreover, previous studies have shown that people who have both epilepsy and mood disorders tend to have worse seizure outcomes than those without mood disorders.

“A number of genes have been found for epilepsy and understanding if these genes also might be causing depression is important,” Heiman said. “In particular, more studies should be done to understand the relationship between focal epilepsy and mood disorders.”

In the U.S., about 2.3 million adults and more than 450,000 children and adolescents have epilepsy, and anyone can develop the disorder. In 2015, an estimated 16.1 million adults at least 18 years old in the U.S. had at least one major depressive episode in the past year, according to federal figures.

Insel BJ, Ottman R, Heiman GA
Mood disorders in familial epilepsy: A test of shared etiology
Epilepsia. 2018;00:1–9. https://doi.org/10.1111/epi.13985

Top Image: Gabriel González-Escamilla, Wellcome Images

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