Well, perhaps in this fanfiction, some of Naruto's friends are also in the mental hospital for various reasons. For example, Sasuke might be there because of his inner turmoil and the darkness he has carried. The story could explore how they interact and support each other in this unusual setting, which is quite different from their usual ninja world adventures.
One possible scenario could be that Naruto was severely injured in a battle, perhaps against a powerful new enemy. He was brought to the hospital, but his injuries were too grave to be healed, and he passed away surrounded by his friends and family, leaving everyone in deep sorrow.
Another theme is friendship and teamwork. Just as in Naruto where the characters rely on each other, in these fanfictions, the Naruto characters team up with the General Hospital staff. They work together to solve problems, whether it's a medical emergency or dealing with a difficult patient. It shows that no matter the universe, the power of friendship is important.
Sakura could also be a main character. As a medic - ninja, she might be involved in Naruto's treatment in the mental hospital. She could bring her own knowledge and her relationship with Naruto into play, adding depth to the story.
Well, one possible plot could be that Naruto has faced so many traumas during his battles and the loss of his friends that it finally takes a toll on his mental health, leading to him being sent to a mental hospital. In the hospital, he might have to deal with his inner demons, like the Nine - Tails' influence on his psyche, and try to find a way to heal.
Hinata would also be very involved. She has deep feelings for Naruto. She might be at his bedside in the hospital, praying for his recovery. After his death, she would be heartbroken and might have to find a new purpose in life without Naruto.
Another character could be Kakashi. He might be the one who doubts the decision to send Naruto to the mental hospital. He could secretly visit Naruto and try to train him in mental fortitude techniques so that he can get out of the hospital sooner.
There's a fanfic where characters from Naruto interact with the medical staff in General Hospital. It shows how the different personalities from Naruto, like Naruto's determination and Sakura's medical knowledge, blend with the drama and medical cases in General Hospital. The story is full of unexpected twists and turns.