In 1949, an Australian psychiatrist named John Cade discovered therapeutic dosing of lithium as a mood stabilizer for the pharmacologic treatment and prevention of manic or depressive episodes, which reduced the risk of suicide in treated individuals. A meta-analysis and systematic review published in July 2020 compiled articles published from 1946-2018 to assess the correlation between lithium content in public drinking water and suicide rates therewith associated. In 2018, the ratio of male:female deaths by suicide was 3:1; the authors of this 2020 article therefore assessed male, female, and combined suicide rates in the articles compiled for analysis. 

After excluding duplicate articles from the initial database search, 260 articles were screened for content applicable to the goal of the analysis. 219 articles were excluded and 41 were assessed for eligibility. No language restrictions were made. Of the 41 remaining articles, 26 were excluded as non- primary sources of information. 15 articles were included in the authors’ qualitative synthesis and 9 were finally included in their meta-analysis. The qualitative synthesis included 4 studies each from Japan and Austria, 3 from the United States, and 1 each from England, Greece, Italy, and Lithuania. The total number of regions, counties, and cities assessed for lithium levels in drinking water and corresponding suicide mortality rates was 1286. The majority of these studies showed statistically significant inverse correlations between lithium levels measured in local drinking water and the local suicide mortality rates. 

This research poses an important public health question which in some ways has already been answered: should we add an ion with known benefit to public water supplies? In 1901, research began on fluoride and its effect on dental health in response to dental health crises. After years of collecting evidence and making proposals, in 1945 Grand Rapids, MI, USA was the first city to fluoridate its public drinking water. Today, almost two-thirds of Americans benefit from fluoridated water supplies. If enough equally powerful evidence to that which fluoridation research produced is collected to support the lithiation of public water supplies in the face of rising mental health crises, will the same pattern hold true? Another question posed too often of late: will humans place their trust in science or public opinion? 

Information on fluoridation obtained from https://www.nidcr.nih.gov/health-info/fluoride/the-story-of- fluoridation 

 

By Jordan Lyons, PharmD Candidate 2020 

Full article available at https://www.cambridge.org/core/journals/the-british-journal-of-psychiatry/

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