Philadelphia, PA, May 2, 2012 – Although the two disorders may seem dissimilar, epilepsy and psychosis are associated. Individuals with epilepsy are more likely to have schizophrenia, and a family history of epilepsy is a risk factor for psychosis. It is not known whether the converse is true, i.e., whether a family history of psychosis is a risk factor for epilepsy.
Multiple studies using varied investigative techniques have shown that patients with schizophrenia and patients with epilepsy show some similar structural brain and genetic abnormalities, suggesting they may share a common etiology.
To investigate this possibility, researchers conducted a population-based study of parents and their children born in Helsinki, Finland. Using data available in two Finnish national registers, the study included 9,653 families and 23,404 offspring.
Individuals with epilepsy had a 5.5-fold increase in the risk of having a psychotic disorder, a 6.3-fold increase in the risk of having bipolar disorder, and an 8.5-fold increase in the risk of having schizophrenia.
They also found that the association between epilepsy and psychosis clusters within families. Individuals with a parental history of epilepsy had a 2-fold increase in the risk of developing psychosis, compared to individuals without a parental history of epilepsy. Individuals with a parental history of psychosis had a 2.7-fold increase in the risk of having a diagnosis of epilepsy, compared to individuals without a parental history of psychosis.
There have been multiple theories regarding the link between epilepsy and psychosis, but most have been predicated on the idea that epilepsy has toxic effects on the brain. However, combined with prior genetic and neurodevelopmental evidence, these new findings suggest a much more complex association, which likely includes a 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.
Dr. John Krystal, Editor of Biological Psychiatry, commented: "We have long 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."
The article is "Evidence for Shared Susceptibility to Epilepsy and Psychosis: A Population-Based Family Study" by Mary C. Clarke, Antti Tanskanen, Matti O. Huttunen, Maurice Clancy, David R. Cotter, and Mary Cannon (doi: 10.1016/j.biopsych.2012.01.011). The article appears in Biological Psychiatry, Volume 71, Issue 9 (May 1, 2012), published by Elsevier.
Notes for editors
Full text of the article is available to credentialed journalists upon request; contact Rhiannon Bugno at +1 214 648 0880 or Biol.Psych@utsouthwestern.edu. Journalists wishing to interview the authors may contact Mary Clarke at +353 (0)1 8093854 or firstname.lastname@example.org.
The authors' affiliations, and disclosures of financial and conflicts of interests are available in the article.
John H. Krystal, M.D., is Chairman of the Department of Psychiatry at the Yale University School of Medicine and a research psychiatrist at the VA Connecticut Healthcare System. His disclosures of financial and conflicts of interests are available here.
About Biological Psychiatry
Biological Psychiatry is the official journal of the Society of Biological Psychiatry, whose purpose is to promote excellence in scientific research and education in fields that investigate the nature, causes, mechanisms and treatments of disorders of thought, emotion, or behavior. In accord with this mission, this peer-reviewed, rapid-publication, international journal publishes both basic and clinical contributions from all disciplines and research areas relevant to the pathophysiology and treatment of major psychiatric disorders.
The journal publishes novel results of original research which represent an important new lead or significant impact on the field, particularly those addressing genetic and environmental risk factors, neural circuitry and neurochemistry, and important new therapeutic approaches. Reviews and commentaries that focus on topics of current research and interest are also encouraged.
Biological Psychiatry is one of the most selective and highly cited journals in the field of psychiatric neuroscience. It is ranked 4th out of 126 Psychiatry titles and 15th out of 237 Neurosciences titles in the Journal Citations Reports® published by Thomson Reuters. The 2010 Impact Factor score for Biological Psychiatry is 8.674.
Elsevier is a world-leading provider of scientific, technical and medical information products and services. The company works in partnership with the global science and health communities to publish more than 2,000 journals, including The Lancet and Cell, and close to 20,000 book titles, including major reference works from Mosby and Saunders. Elsevier's online solutions include SciVerse ScienceDirect, SciVerse Scopus, Reaxys, MD Consult and Mosby's Nursing Suite, which enhance the productivity of science and health professionals, and the SciVal suite and MEDai's Pinpoint Review, which help research and health care institutions deliver better outcomes more cost-effectively.
A global business headquartered in Amsterdam, Elsevier employs 7,000 people worldwide. The company is part of Reed Elsevier Group PLC, a world-leading publisher and information provider, which is jointly owned by Reed Elsevier PLC and Reed Elsevier NV. The ticker symbols are REN (Euronext Amsterdam), REL (London Stock Exchange), RUK and ENL (New York Stock Exchange).
Editorial Office, Biological Psychiatry
+1 214 648 0880