I have one more final addition here. This is a link to a pdf, so be forewarned.

https://www.gwern.net/docs/lithium/2017-ishii.pdf&ved=2ahUKEwijzMO154zrAhVrkeAKHZaTC24QFjALegQIAxAC&usg=AOvVaw2E4lk3nRjQaC9OwV1UeUgW

Therefore, at least in regards to suicide, relatively higher lithium levels (though much lower levels than therapeutic ones) may be associated with lower suicide rates. With regard to gender diferences, Table 1 shows that four stud- ies found a signifcantly inverse association with lithium levels in drinking water only in males (male response to trace lithium) whereas three studies found an association only in females (female response to trace lithium). There- fore, the gender diference efect is yet to be determined. Nonetheless, Kanehisa et al. (2017) investigated the lithium levels of 199 lithium therapy-naïve patients includ- ing 31 patients with suicide attempts, 21 patients with self- harm, and 147 control patients. There was a signifcant diference (p = 0.043) between the three groups, whereby patients with suicide attempts had signifcantly lower lith- ium levels than control patients (p = 0.012) in males but not females. This is consistent with male responses to trace lithium. Sher (2015) suggested one possibility that higher levels of lithium in drinking water decreases suicide rates among men by reducing impulsivity and aggression, and another possibility that lithium reduces suicidality in men by decreasing testosterone levels. Therefore, in our opin- ion, trace lithium may be efective for suicide prevention particularly in males as opposed to females. This should be investigated in randomized, placebo-controlled trials in the future.