In at least one respect, it seems the film has done a good job and accurately representing reality, as a man who suffers from a similar disorder to that of the character of Arthur Fleck, says Joaquin Phoenix does a realistic job of portraying a man suffering from something that causes him to burst out in uncontrollable laughter.
While Joker may be based on a comic book character, the movie is designed to feel as realistic as any character based drama.