Shared etiology of psychosis and epilepsy

Epilepsy and psychosis may seem dissimilar, but they are associated. People with epilepsy are more likely to have schizophrenia. Additionally, a family history of epilepsy is a risk factor for psychosis.

Many studies have revealed that people with schizophrenia and those with epilepsy have similar structural brain and genetic abnormalities. They may in fact have a common etiology. So to investigate this possibility, researchers conducted a study of parents and their children using data from two Finnish national registers. The study included 9,653 families including 23,404 children.

They found that individuals with epilepsy had a 5.5-fold increase in the risk of having a psychotic disorder, a 6.5-fold increase in the risk of having bipolar disorder, and an 8.5-fold increase in the risk of having schizophrenia. They also discovered that these conditions cluster in specific families. People whose parents had epilepsy had a 2-fold increase in the risk of developing psychosis. People whose parents had psychosis had a 2.7-fold increase in acquiring epilepsy.

These findings suggest there is a complicated relationship between the two diseases which likely includes shared genetic vulnerability.

“Our evidence that epilepsy and psychotic illness may cluster within some families indicates that these disorders may be more closely linked than previously thought. We hope that this epidemiological evidence may contribute to the on-going efforts to disentangle the complex pathways that lead to these serious illnesses,” said Dr. Mary Clarke, first author of the study and lecturer at royal College of Surgeons in Ireland.

“We have known that particular types of epilepsy were associated with psychosis. However, the finding that a parental history of psychosis is associated with an increased risk of epilepsy in the offspring strengthens the mechanistic link between the two conditions,” said Dr. John Krystal, Editor of Biological Psychiatry.

Source: ScienceDaily, Biological Psychiatry