An international research consortium has discovered that many common genetic variants contribute to a person's risk of schizophrenia and explain at least a third of the risk of inheriting the disease, providing the first molecular evidence that this form of genetic variation is involved in schizophrenia. The researchers also found that many of these DNA variations also are involved in bipolar disorder but not in several non-psychiatric diseases. The findings, reported by the International Schizophrenia Consortium and published online in the journal Nature, represent a new way of thinking about the genetics of psychiatric diseases, which seem to involve not only rare variants but also a significant number of common ones as well. read more