Iruka would be extremely worried. He's always been like a father figure to Naruto. He would spend a lot of time with Naruto, trying to keep him calm and stable. His friends from the Hidden Leaf would also rally around him. They might organize themselves into shifts to look after Naruto. For example, Choji could bring him his favorite food during his bad days, hoping to cheer him up, and Ino could use her mind - transfer jutsu in a non - invasive way to try and understand what's going on in Naruto's head.
Sasuke, who has his own complex relationship with Naruto, would probably be in denial at first. He's seen Naruto as this strong - willed person, and the idea of him having schizophrenia would be hard to accept. But as time goes on, he would become more protective. He might train Naruto in ways to control his mind during the episodes, using his own experiences of mental discipline. As for Kakashi, he would be empathetic. He has his own traumas, and he would do his best to support Naruto, maybe sharing his own stories of dealing with difficult mental states.