system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 Is Lithium the medicine the same as Lithium the battery?

Like, the very same? Does it at least goes through different processings? How the fuck can a metal be a medicine?
gpt
Lithium is the same element in both cases, but it is involved in different chemical compounds.

In a lithium battery the lithium is part of lithium cobalt oxide, one lithium atom, one cobalt, and two oxygen. In the medication it is lithium carbonate, which is two lithium atoms, one carbon, and three oxygen. Atoms behave very differently when in different chemical compounds so while the atom is the same they are very different things.

As for why precisely lithium works to treat some kinds of mental disorders... we don't really know why it works, but it does seem to be effective.