A friend of mine had an awful time due to someone assuming a character was based on them. This person wrote to the publishers threatening legal action if they published it; wrote to the university where my friend lectures, accusing her of all sorts of unethical behaviour; wrote to the other university where my friend was doing a PhD in literature and told them they shouldn’t give her the doctorate, after accusing her of all sorts of things, and so on. It was a real nightmare and lasted for over a year. The book is yet to be published but my friend has finally stopped seeing the therapist. Of course, the character in the book (who, by the way is a sympathetic character, one of the ‘good guys’) had nothing to do with the person.