February 15, 2014. Although very different in terms of symptoms, multiple sclerosis (MS) and schizophrenia appear to be linked at the genetic level, according to a new study published in Molecular Psychiatry by Ole Andreassen, University of Oslo, Norway, and Anders Dale, University of California, San Diego, and their colleagues. This is not so far fetched, since both disorders appear to have some relationship to the immune system. The evidence is fairly clear in MS, an autoimmune disorder in which the body attacks its own nerve cells, resulting in a variety of problems, from muscle weakness and vision impairment to psychiatric symptoms. In the case of schizophrenia, scientists have found, among other things, that maternal infection during pregnancy elevates a baby’s risk for later developing schizophrenia.
By combining the genetic data of people with the two illnesses (nearly 50,000 participants) and using a new analysis approach, the researchers were able to find several changes to the DNA sequence that are shared between schizophrenia and MS. Interestingly, these genetic differences seemed to have opposite effects in the two illnesses: The changes that increased risk of MS were associated with a lower risk of schizophrenia. No such overlap was found between MS and other illnesses such bipolar disorder, major depression, and autism, suggesting that among psychiatric disorders, immune system dysfunction is specific to schizophrenia.
With the new method, Andreassen and colleagues could also pick out additional genetic changes that are associated with schizophrenia that were not found in a previous analysis that explored the schizophrenia cohort alone. (For more details, see the related news story.)—Allison A. Curley.