Does Borna disease virus cause mental illness?

January 31, 2012 -- Over the past 30 years, numerous studies have linked Borna disease virus (BDV) with mental illnesses such as bipolar disorder, schizophrenia, anxiety disorder and dementia. Genetic fragments and antibodies to this RNA virus, which causes behavior disorders in a range of mammals and birds, have been found to be prevalent in psychiatric patients, but study results have been inconsistent. Now, the first blinded, case-control study to examine this issue finds no association between the virus and psychiatric illness.

The study, conducted by researchers at the Center for Infection and Immunity at Columbia University's Mailman School of Public Health and collaborators at seven other institutions in the U.S, Germany and Australia, can be found online at Molecular Psychiatry.

The scientists evaluated 198 patients in California with schizophrenia, bipolar disorder and major depressive disorder, carefully matched each one of them with a healthy control of the same sex, age, region and socio-economic status, and tested blood of patients and controls for the presence of BDV genetic material and antibodies to BDV. The investigators hypothesized that if the virus was, in fact, associated with a psychiatric disorder, genetic evidence of infection would be apparent in blood samples taken at the onset and/or at the peak of a psychiatric episode, and antibody evidence would be detectable several weeks afterward. Blood samples were therefore collected within six weeks of the onset of an acute episode or clinically significant worsening of symptoms and six weeks later to allow for changes in viral load or antibody levels. Not only did the researchers find no relationship between mental illness and bornavirus, they found no evidence of active or historical infection with BDV in any of the subjects.

"Our study provides compelling evidence that bornaviruses do not play a role in schizophrenia or mood disorders," says Mady Hornig, MD, director of translational research at the Center for Infection and Immunity.

In a commentary in the same issue of the journal, Michael B.A. Oldstone, MD, an expert in molecular virology and central nervous system infections at the Scripps Research Institute, observes that the design and experimental procedures carried out in the Hornig study provide a gold standard for investigating links between persistent viral infection and human disease.

CII director, W. Ian Lipkin, MD, senior author of the paper, notes that "it was concern over the potential role of BDV in mental illness and the inability to identify it using classical techniques that led us to develop molecular methods for pathogen discovery. Ultimately these new techniques enabled us to refute a role for BDV in human disease. But the fact remains that we gained strategies for the discovery of hundreds of other pathogens that have important implications for medicine, agriculture and environmental health."

Founded in 1922 as one of the first three public health academies in the nation, Columbia University's Mailman School of Public Health pursues an agenda of research, education, and service to address the critical and complex public health issues affecting New Yorkers, the nation and the world. The Mailman School is the third largest recipient of NIH grants among schools of public health. Its over 300 multi-disciplinary faculty members work in more than 100 countries around the world, addressing such issues as preventing infectious and chronic diseases, environmental health, maternal and child health, health policy, climate change & health, and public health preparedness. It is a leader in public health education with over 1,000 graduate students from more than 40 nations pursuing a variety of master's and doctoral degree programs. The Mailman School is also home to numerous world-renowned research centers including the International Center for AIDS Care and Treatment Programs (ICAP), the National Center for Disaster Preparedness, and the Center for Infection and Immunity. For more information, please visit www.mailman.columbia.edu