Lithium in tap water cuts suicide rates

Scientists in Japan have found a strong link between higher levels of the metal lithium in tap water and a reduced incidence of suicide.

Hirochika Ohgami and Takeshi Terao from Oita University led a team who measured the levels of lithium in the tap water of 18 municipalities of a region of Japan called Oitra and compared that against the rates of suicide among the million people who live there. The study published in the British Journal of Psychiatry shows that between 2002 and 2006, in areas where lithium levels were highest, suicide rates were significantly lower.

People with serious mood disorders like bipolar disorder are already treated with high doses of lithium to try and stabilise their moods, but this study shows that much lower doses, perhaps accumulating in the brain over time, may also have a positive impact on suicide rates.

The amounts of lithium in the drinking water ranged from 0.7 to 59 micrograms per litre, and this study raises the issue of whether lithium should be added on large scales to drinking water. That sort of mass and involuntary delivery of medicine is something that will no-doubt stimulate hot debate. The authors emphasize that it is still very early days, and that wider scale studies are now urgently needed to understand more about the affects of lithium in drinking water especially since it is known to have nasty side effects and can be toxic at higher doses.

Another recent study has shed light on how exactly lithium affects the brain and helps stabilize bipolar disorder, something scientists have been quite understood. Professor Adrian Harwood of Cardiff School of Biosciences in the UK, led a study in the journal Disease Models and Mechanisms which has pinpointed a possible pathway that lithium may act through.

Laboratory tests of cell cultures has found that by inhibiting an enzyme called inositol monophosphatase (IMPase), lithium reduces the production of a molecule called PIP3 which is known to play an important role in controlling brain cell signalling. A certain variant of the gene or IMPase, has been previously linked to people with bipolar disorder and it could be that lithium is somehow counteracting changes in that gene. The precise mechanism remains to be discovered but this study points the way for future studies.