There was another conversation in this subreddit a few days ago talking about how stutterers have a higher brain sensitivity to dopamine. In other words, a gross oversimplification would be. less dopamine = better for stutterers. It’s a similar thing for people with tics. When we OD on dopamine, it can (in theory) cause issues. https://ahn.mnsu.edu/services-and-centers/center-for-communication-sciences-and-disorders/services/stuttering/information-about-stuttering/serious-information/types-of-fluency-disorders/stuttering-and-drugs/serotonin-dopamine-antagonists-in-the-treatment-of-stuttering/