Geospatial examination of lithium in drinking water and suicide mortality

Marco Helbich,Nestor D Kapusta,Michael Leitner

doi:10.1186/1476-072x-11-19

Abstract

BackgroundLithium as a substance occurring naturally in food and drinking water may exert positive effects on mental health. In therapeutic doses, which are more than 100 times higher than natural daily intakes, lithium has been proven to be a mood-stabilizer and suicide preventive. This study examined whether natural lithium content in drinking water is regionally associated with lower suicide rates.MethodsPrevious statistical approaches were challenged by global and local spatial regression models taking spatial autocorrelation as well as non-stationarity into account. A Geographically Weighted Regression model was applied with significant independent variables as indicated by a spatial autoregressive model.ResultsThe association between lithium levels in drinking water and suicide mortality can be confirmed by the global spatial regression model. In addition, the local spatial regression model showed that the association was mainly driven by the eastern parts of Austria.ConclusionsAccording to old anecdotic reports the results of this study support the hypothesis of positive effects of natural lithium intake on mental health. Both, the new methodological approach and the results relevant for health may open new avenues in the collaboration between Geographic Information Science, medicine, and even criminology, such as exploring the spatial association between violent or impulsive crime and lithium content in drinking water.

Highlights

One of the first anecdotic evidence of effects of lithium containing water on mental health was mentioned by Cade [1]
In a step-by-step approach, an exploratory spatial data analysis, a global non-spatial regression model, a global spatial regression model, and a local spatial regression model were developed and applied to explore the association that lithium and other factors have on suicide mortality
Non-parametric Spearman’s correlations (Table 1) show that suicide mortality is significantly correlated with mean lithium levels per district, population density, per capita income, the proportion of Roman Catholics, as well as the density of psychiatrists and psychotherapist

Summary

Introduction

One of the first anecdotic evidence of effects of lithium containing water on mental health was mentioned by Cade [1]. Several studies have investigated the relationship between the naturally occurring lithium content in drinking water and suicide mortality [2,3,4,5], a relationship which is plausible since lithium is a well recognized mood-stabilizer and suicide preventive in psychiatric treatment nowadays. This relationship is somewhat surprising, as the level of lithium for therapeutic use is multiple times higher than naturally occurring lithium. This study examined whether natural lithium content in drinking water is regionally associated with lower suicide rates

Results

Discussion

Conclusion