Before I start this post, I would like to say this is NOT a call for "mental illness representation" in League of Legends. I do not care if there are characters with them or without them. I just like to ask questions about the lore.
That being said, how prevalent is mental illness in Runeterra, do you think? Do battle hardened soldiers like Garen and Darius struggle with post-traumatic stress disorder due to the things they've seen on the battlefield? Maybe even Teemo? Is Jinx a sociopath? Does Orianna struggle to cope with losing her human form?