A new systematic review of more than a dozen studies from around the world has confirmed an association between geographical areas with naturally high levels of lithium in the water supply and low rates of suicide. The researchers suggest trials should be undertaken to test whether adding trace levels of lithium to a community’s water supply could improve wellbeing and reduce suicide rates.
Best known today as a treatment for bipolar disorder, lithium’s broader mental health effects have been known for some time. In the early 20th century the mineral was even touted as a general brain health tonic and incorporated into the first recipes for popular soft drink 7-Up.
Despite these known mood-stabilizing benefits, lithium has proved a challenging compound to deliver therapeutically. It can very easily become toxic if sustained doses are too high, which is why it was ultimately banned as a beverage supplement in 1948, and now is primarily only administered as a therapeutic drug under close observation from psychiatrists.
A compelling growing body of evidence is starting to suggest there may be beneficial effects to sustained lithium exposure from natural sources. A number of epidemiological studies have investigated local communities with higher than average levels of lithium in their water supply. The research has found a distinct correlation between higher natural lithium levels in a community’s water supply and lower rates of dementia, violent crime and suicide.
Earlier this year scientists from McGill University presented a novel microdose formulation of lithium designed to slow the progression of Alzheimer’s disease, but that research is still in preclinical stages and yet to move to rigorous human trials.
“The prevalence of mental health conditions and national suicide rates are increasing in many countries,” says lead author on the new study Anjum Memon, explaining the motivation behind this research. “Worldwide, over 800,000 people die by suicide every year, and suicide is the leading cause of death among persons aged 15-24 years."
Administered by psychiatrists under clinical conditions, lithium is known to directly reduce rates of suicidal ideation. A number of focused epidemiological studies have also detected a link between lower suicide rates in a given community and higher natural levels of lithium in their water supply. This new study offers the most comprehensive systematic review of the published evidence to date, encompassing 15 studies.
"This synthesis and analysis of all available evidence confirms previous findings of some individual studies and shows a significant relationship between higher lithium levels in drinking water and lower suicide rates in the community,” says Allan Young, co-author on the new study. “The levels of lithium in drinking water are far lower than those recommended when lithium is used as medicine although the duration of exposure may be far longer, potentially starting at conception.”
The study ultimately suggests lithium could be added to local water supplies as a public health measure to improve general mental health in a community, in much the same way fluoride is added to drinking water to improve dental health. The researchers note this could be of particular benefit to communities with demonstrably higher rates of violent criminal behavior and suicide.
However, dosage is a key unanswered question at this point, and Memon says future trials will be vital to ascertain what level of microdose can confer beneficial effects in a community.
"Next steps might include testing this hypothesis by randomized community trials of lithium supplementation of the water supply, particularly in communities (or settings) with demonstrated high prevalence of mental health conditions, violent criminal behavior, chronic substance abuse and risk of suicide,” says Memon. “This may provide further evidence to support the hypothesis that lithium could be used at the community level to reduce or combat the risk of these conditions."
One recent suggestion for a safe way to conduct an effective randomized clinical trial such as this could be to explore microdose levels of lithium in drinking water supplies on Navy vessels. Rates of suicidal ideation amongst sailors on Navy aircraft carriers are significantly higher than the general population, pointing to a distinct need for better mental health interventions in these environments. Plus, the contained environments of these kinds of vessels enables different dosages to be tested.
Carmine Pariante, from the Royal College of Psychiatrists, suggests more study is of course needed before these kinds of interventions are widely deployed, but lithium is proving incredibly promising at improving well-being in depressed patients.
“This study shows that the boundaries between medication and nutritional interventions are not as rigid as we used to think, opening up the possibility of new treatments that span both domains," says Pariante, who did not work on this new study. "More knowledge of the beneficial properties of lithium and its role in regulating brain function can lead to a deeper understanding of mental illness and improve the wellbeing of patients with depression and other mental health problems.”
The new study was published in the British Journal of Psychiatry.
