Adding the dietary supplements folate and vitamin B12 to treatment with antipsychotic medication improved a core symptom component of schizophrenia in a study of more than 100 patients. The study focused on negative symptoms of schizophrenia -- which include apathy, social withdrawal, and a lack of emotional expressiveness. While the level of improvement across all participants was modest, results were more significant in individuals carrying specific variants in genes involved with folate metabolism. The report from a team based at Massachusetts General Hospital (MGH) will appear in the journal JAMA Psychiatry (formerly Archives of General Psychiatry) and has been issued online.