Manic states are suspected of having a number of different causes - genes or environmental conditions, among others, are thought to influence their occurrence. However, as the pathogenesis of mania is still not clearly explained, attempts are still being made to find factors that may favour its occurrence. Researchersfrom theJohns Hopkins University School of Medicine in theUSA have provided interesting information ,observing that the occurrence of manic states may be influenced by nitrates in meat.