Background: Recent studies have shown that lithium may be effective at reducing suicide at low doses, such as those found in drinking water.
Aims: The purpose of this study was to compare suicide rates with natural lithium levels in the drinking water of various Alabama counties.
Method: Five drinking water samples from each of 15 Alabama counties were collected. Lithium levels were measured in triplicate using an inductively coupled plasma emission spectrophotometer and compared with suicide rate data for the period 1999-2013. Age, gender, and poverty were evaluated as potential confounding variables.
Results: The average measured lithium concentrations ranged from 0.4 ppb to 32.9 ppb between the counties tested. The plot of suicide rate versus lithium concentration showed a statistically significant inverse relationship ( r = -.6286, p = .0141). Evaluation of male-only suicide rate versus lithium concentration data also yielded significant results; however, the female-only rate was not significant. Age standardized suicide rates and poverty when individually compared against lithium levels were also found to be statistically significant; unexpectedly, however, poverty had a parallel trend with suicide rate.
Conclusion: Lithium concentration in drinking water is inversely correlated with suicide rate in 15 Alabama counties.
Keywords: community mental health; epidemiology; lithium; suicide.