It's a chinese novel, and I think the mc's name was Ye Huaijin (?) and he transmigrates to the body with the same name as him but the original owner was put in a mental hospital. The original owner's parents are divorced, while the mc has scholar's syndrome. He goes on to copy poems and publishes No Longer Human by Osamu Dazai. There's also the nurse who originally took care of the original owner. They get together in the end if I recall correctly.