If using body feats beyond your capability affects the body then technically using dojutsu beyond your capability should affect the mind (turn a person insane)
But unlike Obito when he used the Rinnegan, Kakashi using MS didn't have a similar effect. He kept his sanity all along and never gave into hatred, although not having Uchiha chakra could be the main reason it's so, I think it's also because of him possessing the affinity to use dojutsu even if it's little compared to Sasuke's clan.
But unlike Obito when he used the Rinnegan, Kakashi using MS didn't have a similar effect. He kept his sanity all along and never gave into hatred, although not having Uchiha chakra could be the main reason it's so, I think it's also because of him possessing the affinity to use dojutsu even if it's little compared to Sasuke's clan.