Adding lithium to drinking water supplies could help to reduce suicide rates, according to a team of psychiatrists.

Naturally-occurring levels of the chemical are to be measured in supplies in Scotland and compared with suicide rates in the population it serves.

It follows similar studies in the US and Japan which found that suicide rates are higher in areas where there are low levels of lithium in the drinking water.

The chemical is a common treatment for bipolar disorder but is found in many water supplies.

The project was announced at the Royal College of Psychiatrists’ International Congress in London.

Lithium levels will be measured by postcode and compared with Scottish Health Survey and NHS statistics.

The team will also test the impact of adding lithium to water supplies just as fluoride is added to prevent tooth decay.

Professor Allan Young, professor of mood disorders at the Institute of Psychiatry, King’s College, said: “We have a considerable body of evidence that suggests that high levels of the chemical in the water supply could save lives.

“The key to lithium’s impact on reducing suicide as a pharmaceutical agent is in reducing impulsivity as well as depression.

“We are now embarking on urgent research to establish the impact of taking low levels of lithium as medication, as well as adding lithium to the water supply in much the same way as fluoride is added to prevent tooth decay.”

Dr Daniel Smith, from the Institute of Health and Wellbeing at the University of Glasgow, said: “If we can become deficient in calcium and zinc, there is absolutely no reason why we cannot become deficient in lithium.

“Previous studies have not always taken different variables such as poverty and unemployment into account when making this comparison.

“In Scotland, we have ideal conditions in which to carry out this research. A single organisation, Scottish Water is able to measure levels of lithium by postcode and we can make use of the excellent routine data which is available from sources such as the Scottish Health Survey and from the Information Services Division of NHS Scotland.”