Lithium - maybe Nirvana was on to something?

It's widely understood that lead toxicity destroys brain-cells and executive function, robbing people of their humanity. A legacy of Tetraethyllead continues to poison inner-cities to this day. But what if there were a neuro-protective element, something that we're missing in our diets today?

Lithium salts have long been prescribed to help mitigate mood swings, but it's a difficult thing to dose as the effective range is close to the toxic level. However, perhaps we could all use a little lithium in our lives, at a micro-dose level. There is a compelling case that lithium ought to be treated as an essential mineral, and added to multivitamins, given an RDA etc.

Could something as simple as increasing the amount of lithium ingestion in our global population increase IQ and mellow people out enough to help take civilisation to the next level?