Lithium in Water Shown to Curb Suicide

May 15, 2009 -- Tap water spiked with naturally-occurring lithium has been shown to curb suicide, according to a new study from Japan and appearing in the British Journal of Psychiatry.

"[T]he nature of the soil in the dam and the river may be different and the difference may affect the lithium levels in water," explained Takeshi Terao, a coauthor of the paper and a professor at Oita University.

"I do not think [cities should start adding lithium to the water supply], because our study is a preliminary one and further studies are required to establish evidence."

Lithium occurs naturally all over the world. Taken orally, and in much higher doses than are found in the water examined by Terao and his authors, lithium treats psychiatric disorders such as manic depressive disorder.

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Terao and his coauthors found that in 18 communities in the southern Japanese province of Oita, natural lithium levels ranged from 0.8 micrograms per liter to 59 micrograms per liter. The higher the concentration of lithium, the less likely the residents of that province were to commit suicide.

Exactly how lithium works in the brain is still a mystery, says Allan Young, a professor at the University of British Columbia who wrote a commentary accompanying the Japanese article. Lithium increases the amount of neurotransmitters such as serotonin, which can help stabilize both the manic and depressive sides of the disorder, but the exact method behind this is still under investigation.

Lithium does have its negative side effects as well. Some are mild: people often feel thirsty when taking lithium. Other side effects can be more severe, like weight-gain and diabetes and kidney problems. Lithium in the water supply could increase these side effects as well, although Terao's study didn't examine this possibility. Since the dosages are so much smaller, presumably the side effects would be as well, although more research is needed to prove that.