The first research study that led to this discovery was based on an unproven hypothesis that drew a correlation between epilepsy and depression, which physicians had suspected since the ancient times. The research was carried out not just to verify if this was true, but also to improve the way patients with the disorder are screened and give them better treatment.
To study this, a team of scientists led by UCL and the Keck School of Medicine of USC studied the brains of people suffering from epilepsy. They used neuroimaging to observe the thickness and volume of grey matter in different regions of the brain. Data was gathered from 24 research centers from 14 countries across five continents (Europe, North America, South America, Asia, and Australia).
To ascertain differences in brain volume and structure, scientists compared the brain scans of 2,149 patients suffering from epilepsy with the brain scans of 1,727 healthy people who served as a control group.
They found that the grey matter in the brains of epileptics was thinner in the cortex, which is the outer layer of the brain, and was also lower in volume in other parts of the brain compared to healthy people. Brains of epileptic patients also had a smaller motor cortex—the part of the brain that controls the movement of our body. Researchers also found that people suffering from epilepsy for a longer time had less grey matter compared to those who did not have the condition for long.
This was also observed in the brain scans of patients suffering from idiopathic generalized epilepsy—a form of epilepsy where brain scans appear normal, as there are usually no observable differences in the brain.
This proves that epilepsy affects other parts of the brain, beyond the epileptic focus—the region of the brain connected with epileptic seizures. According to Dr. Christopher Whelan from the Keck School of Medicine of USC, these differences were “so subtle [that] they could only be detected due to the large sample size that provided us with very robust, detailed data.”
How are epilepsy and depression linked?
This link was established through collaborative research carried out by scientists of Columbia University and Rutgers University in New Brunswick. The research involved a study of families in which epilepsy seemed genetically inherited. The observations were compared with the incidence of mood disorders in the lifetime of family members.
The study established that mood disorders were more prevalent among people suffering from a condition called focal epilepsy (a condition where seizures are triggered in only one part of the brain) than among those with generalized epilepsy, which is when the whole brain is affected.
Significance of the studies
While one study helped scientists understand the brains of people suffering from epilepsy, the other study discovered the link between the type of epilepsy of a patient and their emotional issues.
According to Sanjay Sisodiya, professor at UCL Institute of Neurology & Epilepsy Society, further research needs to be carried out in order to understand the reason for these variations.
The discovery that linked focal epilepsy and mood disorders was significant as well. This knowledge can guide doctors in the treatment of epileptic patients keeping in mind their general well-being. Once a doctor identifies the type of epilepsy as focal epilepsy, the patient can be prescribed treatment for seizures and depression as well, thereby aiming to improve the mental and physical health of the patient.
According to Gary A. Heiman, associate professor in the Department of Genetics at Rutgers University, “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.”
Also read: Severity and frequency of epileptic seizures can be lowered with cannabidiol oil