Honestly, Marijuana or Hashish makes my stutter worse when I do them in too much quantitywhenI'm high on them. But the post-high reduces the anxiety. Since my stutter is quite a lot related to Anxiety, it helps me deal with things with a clear mind. Also, I've tried this, I had a farewell and I smoked did 3-4 puffs of Hashish before going in. That Hashish legit boosted my confidence and helped a lot. And, I only smoke such stuff before going to sleep and usually not during day time Plus, if you think too much about your stutter it'll worsen it too. I'd suggest try both Hashish and Marijuana and try different quantities and find the best that suits you.