Can lithium in drinking water reduce the risk of suicide?

Routine consumption of low levels of lithium in drinking water can decrease suicide rates in people with mental health disorders as well as the general population, according to a growing body of research including an article published by the Journal of Trace Elements in Medicine and Biology.^[]

However, other studies have had conflicting results, indicating lithium may not help prevent suicide.

Suicide prevalent among young people

Suicide, a major public health concern responsible for about 800,000 deaths per year, is the second most common cause of death among people between the ages 15–29, according to a review article published in The British Journal of Psychiatry.^[]

People with mental health conditions are considered to be at a higher risk of suicide. Research from the National Institute of Mental Health showed that in 2020, 4.9% of US adults aged 18 and older had seriously considered suicide.^[] Suicidal thoughts were most prevalent that year among those aged 18–25 in this study.

Occurrence of lithium in nature

Lithium (referred to as the “magic ion”) is a naturally occurring element that can be found in different amounts in grains, vegetables, spices, and drinking water, according to the British Journal of Psychiatry review.

A combination of two stable isotopes, lithium is present in almost all rocks and can enter soil, ground, and standing water through weathering, ultimately resulting in its introduction to public water supplies in varying concentrations.

The health benefits of lithium in water have been recognized for centuries. The first ecological study on lithium, which took place in 1990, indicated a lower incidence of violence and suicide in countries with a high level of natural lithium in drinking water compared with those that had low or medium levels of lithium in their water.

Lithium as medication

According to an article published in the Australian & New Zealand Journal of Psychiatry, lithium is considered the “gold standard” for the treatment of bipolar disorder.^[] It can also be used to treat manic and depressive episodes.

Lithium has been shown to improve mood disorders by affecting several cellular pathways and the expression of many genes. It can increase the expression of glutamine synthetase, increase the availability of vitamin B12, and inhibit glycogen synthase kinase 3β.

However, further research is required to fully understand its mechanism of action, as well as to expand its therapeutic horizons.

In cases where a patient has good response but poor tolerance for it, the serum level of lithium can be reduced to 0.40–0.60 mmol/L. In cases of insufficient response but good tolerance, it can be increased to 0.80–1.00 mmol/L.

Impact on suicide rates

Several studies have associated higher lithium concentration in drinking water with lower suicide rates as well as decreased hospital admissions.

The British Journal of Psychiatry review article, which comprised 15 ecological studies, indicated that lithium in drinking water reduced total, female, and male suicide mortality rates.

Chile and Argentina are known to have the world’s highest natural lithium salt deposits. Studies conducted in Chile reported that the Atacama Region, which has the highest concentration of lithium in the country, had significantly lower suicide rates compared with other regions of the country, according to research published in Frontiers in Public Health.^[]

The article published in the Journal of Trace Elements in Medicine and Biology found that higher levels of lithium in drinking water led to a reduction in suicide rates among men.

However, these and other such studies are limited and a few even reported an inverse relationship between lithium concentration and suicide rates, indicating it's not effective in preventing suicide.

A study published by JAMA Psychiatry found that in a group of veterans who had previously attempted suicide, lithium was no more effective than placebo in reducing suicide-related incidents.^[]

Adverse effects

The adverse effects of lithium are mainly dose-dependent. Toxicity to lithium occurs when the serum level is more than 1.5 mmol/L, as reported in the Frontiers in Public Health research.

A few common adverse effects associated with lithium include:

• Hypothyroidism

• Nausea

• Weight gain

• Vomiting

• Tremor

Chronic use of lithium for decades may lead to serious renal problems such as a decrease in glomerular filtration rate and non-specific interstitial fibrosis.

Future research may help to further assess the relationship between lithium dosage and possible adverse effects, along with reviewing the substance's effectiveness in helping to prevent suicide in patients.