All Mental Toughness requires is that you have SP.
On a side note, I borrowed Epic Mickey from Rusty. Holy guacamole and garlic on a meatless sandwich, this is a fantastic game. The camera is a bit wonky at times, but other than that, the game is pretty much excellent. The atmosphere is very good at conveying just how dark and depressing the world is, and if you go Scrapper, the game is even MORE depressing. And unlike other games where you can just try out choices and reload until you get the morality you want, in this game, it autosaves after a morality choice. While inconvenient in a way, it also does what it sets out to do - basically, makes you stick with your choice. In other words, your decisions matter and have an impact.
And boy do they have an impact. If you're a Heroic Mickey, NPCs react to you fairly positively. If you're a Scrapper Mickey, they look at you with a cold disdain. If you're Heroic, they're generally walking around cheerfully. If you're Scrapper, they're hunched over, staring at the ground instead of where they're going. Some choices have consequences beyond the most immediate resolution, too.
Also, Animatronic Goofy will haunt my nightmares. In a fantastic way.