Further investigation through a population-based study in Finland revealed a strong link between epilepsy and psychotic disorder, bipolar disorder and schizophrenia.
The study also revealed clustering of the association between epilepsy and psychosis within families.
"Share your family medical history with your doctor"
Researchers decided to further examine the link due to past studies having a small sample size and selection bias.
The recent study consisted of 9653 families and 23,404 offspring born in Helsinki between 1947 and 1990. Finnish born individuals are assigned a unique personal identification number at birth that is used in all registers and ensures that accurate information in all registers are linked.
This facilitated researchers in determining psychiatric and neurological outcomes.
The study showed individuals with epilepsy had a 5.5-fold increase in the risk of having a psychotic disorder, 8.5-fold increase in risk of having schizophrenia and a 6.3-fold increase in the risk of having bipolar disorder.
Those with parental history of epilepsy had a 2-fold increase in the risk of developing psychosis and individual with a parental history of psychosis had a 2.7 fold increase in the risk of having epilepsy.
Researchers hope that evidence of a strong common etiology will lead to more investigation into understanding the complex neurological pathways that lead to these illnesses.
Evidence for Shared Susceptibility to Epilepsy and Psychosis: A Population –Based Family Study was published in the May edition of Biological Psychiatry.
The work was supported by the Stanley Medical Research Institute, the Wellcome Trust (UK), a Grable Independent Investigator Award from National Alliance for Research on Schizophrenia and Depression, and the European Community Seventh Framework Program.
Dr. Mary Cannon, one of six authors, was supported by a Clinician Scientist Award from the Health Research Board Ireland. All authors reported no conflict of interest.