Experts Suggest Adding Lithium to Our Drinking Water. It Could Lower Suicide Rates.

Sam Westreich, PhD

Not just in car batteries — it helps prevent suicide. But is this bold public health step going too far?
Water - it's not just vital to health, but might help mental health, thanks to lithium!Quokkabottles on Unsplash

In the United States, the vast majority of citizens receive water from a community water system; instead of drawing from their own individual well that taps an aquifer, they receive water flowing to their home via a larger water management system, run by their community.

Many of those community water systems add fluoride in trace amounts to the water. About 75% of all U.S. citizens on a community water system receive fluoridated water.

The system’s been in place for more than 75 years, and it’s paying off. The CDC estimates that fluoridated water has led to an approximately 25% reduction in cavities among both children and adults. The practice isn’t just in the U.S.; it’s performed by 25 countries around the globe.

Despite what some fringe conspiracy theorists believe, fluoridation has been a success story. But the U.S. government of the 1950s is very different from the government today, and many citizens place far less trust in the government today.

Could a similar public works project pass today? What if we had another additive to water — one that could help prevent something far worse than cavities?

What if we could add tiny amounts of a substance to publicly available water and reduce suicides, improving the overall mood of both adults, teens, and children?

It sounds crazy, and I can already see the wildly panicked uproar from many people who read the headlines and not the article itself. But this idea may not be as crazy as it sounds at first — and earlier this year, a scientific review article came out with a deep dive on the topic.

Let’s talk about lithium.

I’m so happy ’cause today I found my friends

Lithium (and more specifically, lithium salts, where the elemental lithium is bound to another molecule) has been used for mood stabilization for more than 100 years, off and on since the 1870s. It was first used to treat gout, as it helped dissolve the uric acid crystals that built up in the disease. Gout was associated with a number of mental disorders, including mania, and lithium seemed to calm these.

In 1949, Australian psychologist John Cade reintroduced lithium as a method for treating mania and other depressive disorders. The treatment worked, but it needed careful monitoring; too much lithium, and it could cause severe side effects or death.

For a little while, lithium was “crazy popular” as a treatment for manic-depressive illness, including bipolar disorder. It’s featured prominently in Western culture, in everything from American Psycho to Garden State to the eponymously titled song by Nirvana. It was even an ingredient in 7-Up, the soft drink (although it’s no longer added!).

Today, lithium is still widely prescribed for a range of different disorders, including:

  • Bipolar disorder
  • Schizophrenic disorders
  • Major depressive disorder (the medical term for diagnosed depression)

It’s also sometimes prescribed for other mood disorders in young adults and children, often in combination with other treatments. This isn’t explicitly approved by the FDA, but it still commonly occurs.

Puttin’ it in the water supply

Before we start widely dosing the population with lithium, we should answer a few questions first:

  1. How much lithium do you need to consume in order to start seeing any effect?
  2. How much lithium do you need to consume to start seeing negative side effects?
  3. How much lithium do you need to consume in order to risk people being poisoned?

To answer these questions, let’s turn to the Perspective article published earlier this year in the journal Frontiers of Public Health, by Pablo Araya, Camila Martinez, and Jorge Barros, from the Pontificia Universidad Católica de Chile.

The authors noted that we need to differentiate between the therapeutic dose, versus trace levels.

  • The therapeutic dose is how much a patient might be prescribed, which is usually between 0.6–1.0 mmol of lithium per liter, or about 600–1,200 mg of lithium carbonate.
  • Trace levels of lithium are much lower, at 0.005 mmol per liter, or about 0.4 mg per day.

Interestingly, you don’t need to consume the therapeutic dose of lithium to see beneficial effects. In some locations, lithium is naturally present in low doses in the public drinking water, allowing those regions to be used for comparison to other regions without any lithium present in the drinking water.

In a meta-analysis of 16 studies, 11 of them showed that lithium in the drinking water correlated with a decrease in suicide rates, with the suicide rate decreasing as the lithium levels in water increased. These studies took place around the world, looking at the U.S., Japan, Austria, Greece, Portugal, England, and other locations.

Overall, the minimum lithium concentration needed in water seemed to be around 30.7 μg/L (0.0044 mmol/L). Going in the other direction, one village in Argentina showed lithium levels as high as 1,005 μg/L (0.1448 mmol/L) without any noted side effects of lithium, such as altered thyroid hormone levels.

Based on the evidence from naturally occurring lithium-enhanced water sources around the world, adding trace amounts of lithium to water would reduce suicide levels and help stabilize mood in individuals with disorders, without causing negative side effects in the general population.

But does that mean we should start adding it? Could we even do so?

The ethics of adding supplements to water

Let’s introduce a new group, who has thought a lot about the ethics of supplementing human diet with compounds: the Nuffield Council on Bioethics, an independent ethics body based in the United Kingdom.

The Nuffield Council on Bioethics puts out three principles in favor of supplementation, and four against it.

In favor:

  1. The supplement must reduce the risk of becoming ill.
  2. The supplement must protect the health of the most vulnerable.
  3. The supplement must reduce health inequalities.


  1. The supplement must not cause damage.
  2. Any individuals who consume the supplement must consent to its presence.
  3. Supplementation must minimize interventions that affect important areas of life.
  4. Supplementation must not result in coercion or loss of freedoms.

Araya et al. address these concerns for both the principles in favor, and those opposed to, supplementation. Here are their responses to the principles in favor of supplementation:

  1. The supplement must reduce the risk of becoming ill — Overall, this is supported by the evidence of lithium’s protective effects, even at trace levels, and is also backed up by existing practices with fluoridation of drinking water in many communities.
  2. The supplement must protect the health of the most vulnerable — Groups of individuals who suffer from mental disorders would certainly be characterized as most vulnerable! Additionally, lithium-enhanced water would help to reach these groups without restricting the freedoms of others. Anti-gun legislation takes away freedoms (the freedom to own a gun), but water supplementation does not take away freedoms.
  3. The supplement must reduce health inequalities — Water supplementation reaches everyone who consumes water from a community water management system, regardless of their socioeconomic status.

And their responses to the opposing principles from the Nuffield Council:

  1. The supplement must not cause damage — Overall, there aren’t adverse effects reported for trace amounts of lithium supplementation, but this would likely need further study. We’d want to do additional studies to work out where the “sweet spot” is, and ensure that, with as wide a sample group as possible, we don’t see negative side effects.
  2. Any individuals who consume the supplement must consent to its presence — Tricky, as there’s no way to obtain consent from every individual, but if this proposal was passed by public vote, this could be taken as a measure of consent, similar to how fluoridation is handled.
  3. Supplementation must minimize interventions that affect important areas of life — This may butt up against the idea of water as being “pure,” the authors note, but it’s also allayed by current practices. Water from any municipality contains trace minerals already, so lithium-enhanced water would not be any pure than already-provided water.
  4. Supplementation must not result in coercion or loss of freedoms — There’s no loss of freedoms here; individuals are always free to install a filter or consume bottled water instead of tap water.

In Summary: The dose makes the poison

I know that there are already conspiracies about adding fluoride to our water, and plenty of fictional storylines about a totalitarian government applying draconic treatments to its entire population, often with a focus on the poor and downtrodden.

It’s important to note that the authors of this review are not suggesting that we start putting therapeutic dosages of lithium into the water supply. That’s a crazy idea; it would lead to widespread poisoning and toxicity, depending on how much water someone consumed and their vulnerability to the compound.

Instead, they are noting that we already see lower suicide rates in places that have naturally occurring trace amounts of lithium in their water. This is not “everyone takes an antidepressant pill each morning.” This is “trace amounts, that for most people will be unnoticeable, but may slightly help people suffering from depressive disorders so that they can obtain individualized treatment.”

It wouldn’t cure depression in the wide population. It won’t replace our immediate and drastic need for a better healthcare system.

But it could offer small but noticeable benefits for the wider population, as a realistic method to treat the entire public at large.

We already fluoridate our water, to reduce cavities in the population. We add iodine to our salt, to keep our thyroids healthy and avoid goiters.

Should public health groups consider adding trace levels of lithium to drinking water, for potential suicide reduction?

Similarly, would you drink tap water in a community where lithium naturally enters the tap water, and the community shows lower suicide levels?


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A microbiome scientist working at a tech startup in Silicon Valley, Sam Westreich provides insights into science and technology, exploring the strangest areas of biology, science, and biotechnology.

Mountain View, CA

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