It's something in the water

Lithium in drinking water has 'anti-suicide' effect
In Japan's Oita Prefecture, cities with higher levels of lithium in their drinking water experienced lower rates of suicide. The study, in the British Journal of Psychiatry, made me wonder if governments should add lithium to the water supply. Hirochika Ohgami and colleagues at Oita University found a slight, but statistically significant correlation after analysing suicide rates in 18 municipalities between 2002 and 2005. 

The amount of lithium in drinking water would seem far too low to offer any clinical benefit, since people with bipolar disorder routinely take hundreds of times more lithium each day. But Ohgami's team points to another study showing that people with bipolar disorder who don't respond to lithium are still less likely to attempt suicide after taking the drug. "It seems probable that the anti-suicidal effect of lithium may be unrelated to the mood-stabilising effects and that very low lithium levels may possess an anti-suicidal effect," they write.