Shikamaru, being the intelligent and perceptive one, would probably figure out Naruto's identity change quickly. He might be a bit annoyed at the secrecy but would also recognize the importance of it. He would keep an eye on Naruto in his new identity and offer his strategic advice if needed.
Sakura would be worried at first. She has always cared about Naruto and would be concerned that he's in some kind of trouble. However, she would also be one of the first to try and support him in his new identity, especially if it means helping Naruto achieve a greater good.
Sasuke might be initially suspicious. Given their complex relationship, Sasuke would likely want to know the real reason behind Naruto's identity change. But once he understands the motives, he might respect Naruto's decision if it's for a good cause.
Sakura might be initially shocked. But then she would try to find a medical explanation for it. She'd probably be concerned about whether it was harmful to Naruto or not. Sasuke would likely be more stoic about it. He might see it as a sign of Naruto getting stronger in some new and strange way. And he'd be secretly intrigued to see how this new development would affect Naruto's abilities. Shikamaru would probably just sigh and say something like 'What a drag, Naruto. Now you look even weirder.' But he'd also start thinking about the strategic implications of Naruto having this new appearance in battles.
His friends from Team 7, like Kakashi, would feel responsible for Naruto's situation. Kakashi would likely use his resources to find a proper shelter for Naruto. Shikamaru and the others might come together to form a sort of support group for Naruto. They would pool their resources, like money and food, and also try to cheer him up by sharing stories and jokes.
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.
The story could develop with Naruto being confused and making mistakes that he wouldn't normally make. His friends would try to help him, but he might push them away because he doesn't understand who they are to him anymore.
His friends' reactions would vary greatly. Shikamaru would be impressed but also concerned about the implications. He'd start thinking about the strategic advantages and disadvantages of Naruto having this power. Choji would be excited and would see Naruto as an even greater protector of the village. Ino would be a bit scared at first, seeing how Naruto's power seems almost uncontrollable when he first shows it. But as she realizes that Naruto has it under control, she would be more supportive. And Hinata would be the most supportive of all. She would be there for Naruto, believing in him no matter what, and would offer her gentle words of encouragement.
His friends would be in shock. Kakashi would take charge of the situation. He would gather all the information about what Naruto was doing before he disappeared. Naruto's friends like Choji and Ino would use their respective skills to help in the search. Ino could try to use her mind - reading jutsu on people who were around Naruto before he disappeared. They would all be determined to find Naruto because he is an important part of their team and the village.
Sakura might be initially suspicious. She is a smart girl and would wonder about the butler's intentions. She might keep a close eye on him to make sure he doesn't harm Naruto in any way.
Sakura would probably be both disgusted and amused at the same time. She might scold Naruto for being so unhygienic at first, but then laugh at his silly antics.
Another reason could be a personal journey of self - discovery. Naruto might feel that his identity as the hero of the village has become a burden or a limiting factor in his growth. Changing his identity could allow him to explore new aspects of himself, away from the expectations and responsibilities that come with being Naruto Uzumaki.
Sasuke would be extremely enraged. He has a deep bond with Naruto, and Naruto's death would likely send him on a quest for revenge against Konoha. He might see it as a betrayal of everything Naruto stood for and fought for.