Kessing LV, et al. - Herein, the authors analyzed if the incidence of dementia in the general cohort covaried with long-term exposure to microlevels of lithium in drinking water. A possible connection was brought to light between long-term increased lithium exposure in drinking water with a lower incidence of dementia in a nonlinear way. Nonetheless, confounding from other factors related to the municipality of residence could not be excluded.