“Researchers began to ask whether low levels of lithium might correlate with poor behavioral outcomes in humans. In 1990, a study was published looking at 27 Texas counties with a variety of lithium levels in their water. The authors discovered that people whose water had the least amount of lithium had significantly greater levels of suicide, homicide and rape than the people whose water had the higher levels of lithium. The group whose water had the highest lithium level had nearly 40 percent fewer suicides than that with the lowest lithium level.” From the article in NYTimes:
http://mobile.nytimes.com/2014/09/14/opinion/sunday/should-we-all-take-a-bit-of-lithium.html?referrer=&_r=1