How Much Would You Be Willing to Pay to Reduce Murders by 30%?

And furthermore, would you be willing to make the change if it meant making changes to the water supply?

From The Big Think

Adding trace amounts of lithium to the drinking water could limit suicides. Two studies, a recent one in Japan and an older one in Texas, have shown that this naturally occurring substance, used as a psychotropic drug to combat bipolar disorder, could have beneficial effects for society: Communities with higher than average amounts of lithium in their drinking water had significantly lower suicide rates than communities with lower levels. Regions of Texas with lower lithium concentrations had an average suicide rate of 14.2 per 100,000 people, whereas those areas with naturally higher lithium levels had a dramatically lower suicide rate of 8.7 per 100,000.

A gated version of the study is available here.  There are other benefits beyond a reduction in suicides.  From the Texas study:

[T]he homicide rates during the decade studied were consistently lower (by 30-50%) in the high- than the medium- or low-Li counties.  The incidences of robbery, burglary, theft and the total crime rates were also lower in the high-Li counties, but the respective differences involving assault were statistically significant.

Drug use was also lower in the area with the highest natural occurring lithium concentrations.

One question I've never seen answered is: How much would it cost a low-lithium city to artificially boost their concentrations to the highest level?  We have experience adding trace elements to the water supply (fluoride), so it can certainly be done.

I decided to do a very rough back-of-the-envelope type calculation to see what the cost per person in lithium is.

I am not a chemist, but my understanding is that a city that wanted to increase the elemental lithium in the water supply would use lithium carbonate (if I'm mistaken here, please let me know).  The largest bulk price I could find for lithium carbonate is 50kg for $3842.82 (Source), which works out to $76.86/kg or 7.686 cents per gram.  This should only be used as a rough estimate - the price may be lower (because a city would be buying in far larger quantities) or higher (because the city would need a grade with less impurities than the one quoted).  But for a rough back-of-the envelope calculation, it works.

A city with no-to-little elemental lithium would need to add 70 micrograms/L of elemental lithium to the water supply.  Since we're adding lithium carbonate (not pure lithium), we would need roughly 200 micrograms/L. (For reference, there are a million micrograms in a gram).

The average Canadian domestic user uses just over 100,000 L of water a year (Source).  At 200 micrograms/L, we would need to add roughly 20 grams per person of lithium carbonate for a total cost of $1.53 per person, or $153,000 per 100,000 people.

The city of Toronto has 3.3 murders/100,000 people (Source).  A 30% reduction in this rate would lower it by 1 murder per year per 100,000 people.  If our rough back-of-the-envelope calculations are correct and the lithium carbonate method works like the Texas study suggests, $153,000 buys us one less murder.  That does not take into account the reductions in rapes, suicides, drug use or thefts.

Will it work?  I don't know.  It seems like it would be worthy a pilot study or two. Although those levels of elemental lithium are believed to be safe, there may be side-effects we are not considering.  There are ethical considerations as well, but it is hard to make a case that adding fluoride to the water supply is ethical but lithium is not - and we've been adding fluoride to drinking water for over half a century. 

Edited to add: The Texas study grouped counties into four groups: High lithium (70-160 micrograms), Medium (15-60), Low (0-12) and Low excluding big cities (0-12).  If we compare the first group to the fourth, high lithium counties have, per 100,000 population:

• 5 fewer murders
• 5 fewer suicides
• 22 fewer rapes
• 310 fewer burglaries
• 751 fewer thefts

(all of which are statistically significant at the 5% level).  There may be a multitude of other factors causing this than lithium levels.  There is no guarantee that artificially raising lithium levels to get a county to go from low-lithium to high-lithium would provide these results.  But given a (very rough) cost of $153,000 per year, isn't it worth investigating?

Comments

[Fountain Pumps]

Given the practice of the cities of Vancouver and Victoria from dumping sewage into the Strait of Georgia, remind me not to drink water the next time I am in White Rock. The water comes from the mountains of North Shore of Vancouver. Can be special but we have not found a way to live in salt water yet.

[westslope]

Actually, the White Rock water is from a deep well and is, by choice, not treated with chlorine. It looks and tastes much better than the water delivered from the salmon-destroying reservoirs located in North Vancouver. Though I'm sure that Victorian lawns do not care.

I mentioned White Rock's proximity to the Pacific Ocean because I was about to rant on about how the municipality of White Rock uses 2-stroke leaf blowers to clean up sidewalks and similar. You see White Rock enjoys excellent air quality (and much less rain than North and West Vancouvers). But the Fraser Valley airshed occasionally plugs up with smog and a healthy amount of small particulate matter that makes people sick and kills a few others.

I thought the use of unchlorinated water and 2-stroke leaf blowers at the healthy, clean air end of the Fraser Valley airshed made for an interesting constrast.

[Robert Enders]

Boy am I late to this thread. Perhaps it would be better to widely publish the findings, then make lithium available over the counter as a food additive or in pill form. If it's establish that people who consume regular amounts of the element have better mental health, then people will feel more comfortable with the idea of taking lithium.

[Blikktheterrible]

K-"That's how you model the things you know. But, you've neglected the question of whether the expected value of the things you never imagined, and therefore never considered, is negative. But if we agree on the the correct recourse, maybe we can agree to disagree about the reasons."

So, we should assume that the result will be somewhat worse than what the model predicts. The question is how much. You seem to be advocating that we discount all expected values absolutely when losses relative to the status quo are possible. First of all, I think losses relative to the status quo are a possible outcome of every decision (even the decision to do "nothing"). Second, I don't think absolute discounting is optimal. Maybe it is sometimes, depending on how much we know (or, more accurately, how confident we are in what we know), but I think it's often better to go with a good guess than to cling to what knowledge in which we have absolute confidence (which I think we would agree shouldn't be ANY knowledge).

I would like to add that there are really multiple connected issues being argued here. Some people are arguing about whether lithium is/could be beneficial in the ways that Mike originally suggested. Others, like myself, are interested in the issue of whether such benefits would warrant government action, assuming both that those benefits were observed and that political systems would allow that intervention. Others are trying to address the question of whether it would be beneficial to society to allow these sorts of government interventions in the first place. These are all interesting questions, but I don't feel particularly qualified to make much comment on the first or the last, hence my focus on the second issue. However, I would like to make it clear that while my arguments would be irrelevant if the first or last question were answered in the negative, I'm entirely open to those possibilities. I'm agnostic at this point about them both.

Robert Enders-"If it's establish that people who consume regular amounts of the element have better mental health, then people will feel more comfortable with the idea of taking lithium."

But what if, for the sake of argument, the "mental health" benefits were entirely external to the person consuming the lithium . More generally, the issue is what to do if lithium consumption involves an externality.

[K]

I'm not advocating some arbitrary additional discounting. I'm just saying that the model expectation represents a lower bound on the expected harm, thus prudence is advisable. I don't even advocate focusing on the first moment or even the probabilities of disaster. Assume that bad things are going to happen and worry about what we are going to do when they do. And above all, place the burden of proof of safety on those who expect to profit from the project, and find ways to ensure that they will have the means to make restitution when things fail.