An investigation into the association between suicide mortality rate and lithium levels in potable water: a review study

Abstract

This study aimed to investigate the association between lithium levels in potable water and suicide mortality rates in the total inhabitants. We systematically searched Embase, PubMed/MEDLINE, Scopus, PubMed Central (PMC), Google Scholar databases, as well as medRxiv using the following keywords: drinking water, lithium, standardized mortality ratio (SMR), tap water, suicide, and ground water. Pearson regression analysis was used to test an association between variables with 95% confidence interval (CI). A value of P < 0.05 was considered significant. A total of 16 eligible articles were identified. Lithium concentrations in drinking water range from 0.4 to 32.9 μg/l. Average rates of suicide mortality (per 100 000 capita) range between 0.790 (±0.198) and 123 (±50). About 16 original studies confirmed the inverse relationship between lithium concentrations in potable water and suicide mortality rates (R = −0.576; R2 = 0.3323; 95% CI, −0.820 to −0.325; β = −0.3.2; P = 0.019). High lithium concentrations in potable water were associated with decreased suicide rates. We concluded that lithium concentration in potable water was inversely associated with suicide mortality rates among a total population. However, further research is required to clarify the relationship between lithium concentrations in drinking water and suicide rate.

Severe methodological problems in a recent review and analysis of the association between lithium concentration in potable water and suicide rates

“…The recent paper by Fadaei (2023) that explored the association between suicide mortality and lithium concentrations in potable water deserves comments. While this paper is presented as a review, the main analysis is rather an ecological study, a design known for having major methodological limitations.…”

The interplay of psychopharmacology and medical conditions

“…We greatly appreciate the thorough analysis and methodological concerns raised by Martin Plöderl and Florian Naudet in their commentary (Plöderl and Naudet, 2023) on the review by Fadaei (Fadaei, 2023), examining the association between suicide mortality and lithium concentrations in drinking water. Indeed, mixed metrics can bias regression results.…”