Screenshot of google in the “People also ask” section with the question “What was Tim Curry diagnosed with?” followed by the question “Why isn t Tim Curry in Harry Potter?” And the answer to that is “Tim Curry, a lifelong Harry Potter fan, was offered the role of Snape, but turned it down after learning the film would include Harry Potter, a character he dislikes.”
https://nyc3.digitaloceanspaces.com/pixelkitchen/media_attachments/files/111/235/877/684/105/671/original/c4dd720d379e1409.jpeg