Researchers in three studies have found a common genetic cause behind schizophrenia and bipolar disorder, two mental health conditions that were previously thought to be unrelated. Scientists pooled information on approximately 15,000 schizophrenia patients and 80,000 people who did not have the disorder. They found that thousands of tiny genetic mutations called single nucleotide polymorphisms (SNPs) are responsible for about one third of the risk of developing schizophrenia. Investigators...