Even doctors can be "superstitious," like insisting on wearing a particular pair of shoes for surgery, or sticking to a specific method for bandaging a patient's wounds.
This is not really superstition, just a form of mental suggestion.
Its effects are both real and visible.
In the case of Li Xiaoye, Jiang Lang did everything he possibly could, but to say that just because the illness was cured, his imagination would be gone, that's impossible.
This is entirely because, in the past, every time he wrote a good piece, he would act crazy and manic, thus developing the subconscious belief that 'crazy and manic = can write good works'.
When a person is young, if they get shocked every time they touch a flower, then to that person, flowers become as terrifying as high-voltage power lines.
They will be scared even when they grow up.
Humans can eat crabs and tomatoes because they have established a sense of 'these things are safe' from a young age.