I've been trying to remember this novel, probably from the 1990's or early 2000's. The main character and the antagonist are both women (they may have had some relationship in the past; possibly they're related?) It's set in the near-ish future, where all forms of mental illness have been cured through, I think, mandatory screening and medication. The main character may be some kind of "mental health" cop? I'm pretty sure the antagonist is a scientist who purposely induces some type of mental illness in herself (tourettes?) to improve her creativity.
The main theme of the book, IIRC, is the question of mental health vs. genius and creativity. As in, if Van Gogh was cured of his bipolar disorder would he still have been a great painter? (I don't remember if that exact analogy is in the book, it's just an example of the book's theme.) There's no virtual reality/cyberpunk involved.