Higher Levels of Lithium Linked to Lower Suicide Rates

They found a statistically significant inverse relationship—the greater the amount of lithium present, the fewer the suicides. For instance, the highest average level of lithium was found in the Mistelbach region northeast of Vienna. Although this region did not have the lowest average suicide rate among the districts, its average suicide rate ranked 15 out of all 99 districts.

Kapusta and his group then reanalyzed their findings while considering factors known to be capable of influencing suicides in Austria, such as income, religion, and availability of mental health service providers. There was still a significant, inverse relationship between the amount of lithium present in tap water and the number of completed suicides.

Thus, while the study does not prove a causal relationship, it does suggest the possibility that lithium in tap water may temper suicide risk.

As for the argument that perhaps Austrians prefer to drink bottled rather than tap water, Kapusta told Psychiatric News that because Austrian tap water is of high quality, most Austrians do drink tap water. But even if Austrians didn't drink tap water, the lithium present in it could still be absorbed into their bodies via cooking and bathing, he said.

So if lithium in tap water can indeed help counter suicides, should traces of lithium be added to tap water to help protect people from suicide, just as fluoride is often added to tap water to help protect people from dental caries? Not at this time, Kapusta stated. "The scientific evidence is growing, but it is still low and needs to be further strengthened," he said. Also, it's possible that raising the levels of lithium in tap water might have adverse effects on unborn babies, since lithium concentrations in the brain increase during the first trimester of gestation. Additionally, lithium can cause adverse effects such as hypothyroidism, kidney failure, and other problems.

Currently, no country or city appears to be adding lithium to tap water to reduce the risk of suicides, Takeshi Terao, M.D., Ph.D., told Psychiatric News. Terao, a professor of neuropsychiatry at Oita University in Japan, was one of the researchers who conducted the 2009 study demonstrating an inverse link between levels of lithium in tap water and suicides in Japan.

Perhaps the best resource for learning whether lithium can prevent suicides and whether levels of lithium in tap water should be increased as a suicide-prevention measure may lie in a region in northern Chile called Salar de Atacama. Ground water in this region contains some of the highest lithium levels in the world. Kapusta and his colleagues are now obtaining suicide statistics from that region and considering other issues, such as renal and thyroid function. "If any American psychiatrists are interested in such a venture, we look forward to collaboration," he said.