Not a placebo controlled trial, but interesting for a number of reasons. NAC pops up a lot of course, but guanfacine was also one of Goldstein's drugs. Since a lot of my symptoms seem tied to adrenaline release, I've always been interested in alpha and beta blockers. I tried propranolol and didn't respond well, but always been interested in guanfacine.
https://www.sciencedirect.com/science/article/pii/S2667257X22001000
https://www.sciencedirect.com/science/article/pii/S2667257X22001000