Lithium the lifesaver?
Lithium is a naturally occurring salt used by psychiatrists to stabilise mood in those with bipolar disorder, the condition in which moods swing between the blackness of depression to the euphoric state that is called mania, and also to boost the effect of antidepressants.
Although first identified in the 1800s, lithium's medicinal properties in treating mental illness were only identified in 1949
Gradually its beneficial effect in treating bipolar disorder was confirmed, although it was not widely used until techniques to measure its level in the blood were developed. Until then there were concerns about its toxic effects. It was banned in the United States until 1970 for that reason.
It is thought to be particularly important in foetal development since there are high concentrations found in the foetus in the first trimester of pregnancy. Studies of baby rats and goats reared on a diet low in lithium show they exhibit behavioural disturbance.
Lithium is found in foods such as dairy products, eggs, potatoes, peppers, tomatoes, grains and lemons due to its absorbance from soil. Drinking water, from taps or springs, contains significant amounts of it as it's mobilised by rain from rock and soil and dissolves in ground and surface water.
Scientists
In light of knowledge that this salt appears important for mental well-being, some environmental scientists and psychiatrists have begun exploring the link between behaviours such as suicide and levels of lithium in the soil in different regions.
They wished to establish if even small amounts of lithium in water had an impact on suicide and other behaviours.
The first such study was in Texas in 1990 and found counties with higher levels of lithium in the municipal water supply had lower suicide, lower psychiatric admission rates and lower rates of homicide and crime.
A 2009 study from the Oita Prefecture in Japan found levels of lithium in tap water were inversely related to suicide rates. However this study was criticised for using unreliable measures of lithium and not taking account of possible factors that might differentiate Oita from other areas of Japan.
Last year an Austrian team from the University of Vienna published findings in the 'British Journal of Psychiatry'.
They examined suicide rates across all of the country's 99 districts and 6,000 measures of lithium in drinking water were obtained. Their statistical analysis controlled for factors that might vary across different parts of the country and influence the suicide rate.
These confounders included population density, proportion who were Roman Catholic, provision of mental health services and per capita income for each region.
Results were similar to Texas and Japan; suicide rates were higher in areas with lower lithium concentrations in drinking water.
It's possible other aspects of water may also be relevant. It may be that lithium was absorbed through the skin during showering. And could diet likely differ across the regions studied and vegetable intake influence the results more than levels in drinking water? Do three continents' findings mean lithium should be added to drinking water?
There is evidence that lithium is potentially toxic to the foetus during early pregnancy. The possibility is serious enough to warrant extreme caution about supplementing water with it.
Finally, the role of other dietary sources needs to be investigated.
"Let them eat cake" was once the response of the rich to the plight of the poor in the 18th century. It is likely to be some considerable time before "Let them drink water" will be the cynical solution on offer by the wealthy for the mental ravages of poverty in the 21st century.
- Patricia Casey
Originally published in
