Rutgers professor uncovers genetic link between depression and epilepsy
After nearly 10 years of research, Gary Heiman, an associate professor in the Department of Genetics, has discovered evidence supporting the theory that depression and epilepsy are genetically linked.
Records of the possible connection between depression and epilepsy extend as far back as 400 BCE, when Hippocrates, a Greek physician during the Classical period, observed, “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.”
While Hippocrates’s interpretation can be defined as linear, the presence of one leads to development of the other, Heiman’s area of focus lays more in the understanding that depression and epilepsy are more intertwined than a linear relationship.
In certain cases, the stigma of having a disorder such as epilepsy can lead to depression, a psychosocial response, but Heiman’s research bolsters the hypothesis that more biological factors could be at play.
“There is evidence from other kinds of studies that there could be a shared etiology, meaning that some genetic and environmental cause can cause both disorders. Individuals who had depression at some point had an increased risk of later epilepsy, so there seems to be a possible different model (than the one of stigma),” Heiman said.
As a member of the Department of Genetics at Rutgers, Heiman initially pursued his research while a faculty member at Columbia University. Throughout the duration of the study, he has been collaborating with former colleague Dr. Ruth Ottman, a genetic epidemiologist at Columbia University.
To test the genetically-based hypothesis, families that had multiple members with epilepsy were recruited. Both individuals with and without epilepsy were interviewed with a standardized psychiatric instrument to compare their lifelong rates of mood disorders, as well as how those rates compare to those of the general population.
The results had to be categorized by type of epilepsy the individual has to properly evaluate it. Heiman and Ottman discovered that partial (focal) epilepsy, where the seizures start in one area of the brain, and generalized epilepsy, where the seizures begin all over the brain, are rooted in different factors.
They found that people with focal epilepsy were at a much higher rate of lifetime history of mood disorders compared to the people in the family who did not have epilepsy and compared to the people with generalized epilepsy. So the evidence supports the hypothesis for the shared genetic etiology for focal epilepsy, but not generalized epilepsy.
Approximately 2.5 to 3 million Americans have epilepsy, according to a 2014 Healthline Media article. Medication, surgery and diets are typically used to regulate the occurrences of seizures, but comorbidity with depression proves a more complex situation.
The association between depression and epilepsy has been known for some time, individuals under recognize it, which results in it being undertreated, Heiman said. Specialists often are assessing the seizures, but fail to consider the depth of the depression.
The next step then becomes educating individuals experiencing both epilepsy and depression and the public. Conveying the facts and effects of this association poses a challenge, particularly since individuals affected tend to under-recognize it.
For Heiman, who was initially trained as a genetic counselor and is involved in the undergraduate and graduate genetic counseling programs, it is vital to consider the education background of those you are speaking to. Scientific literacy fluctuates greatly among families, so being cautious and communicating effectively are key.
“Individuals with epilepsy and a mood disorder have a worse seizure outcome, (reduced) quality of life, (increased) health care utilization and a higher risk of suicide ideation and attempts. By showing that there’s a biological relationship, at least in focal epilepsy, it’s important for neurologists to recognize that (depression) is also something important to check for," Heiman said.