Yes, stuttering is caused by a dysregulated dopaminergic system in the brain, especially in the striatum and basal ganglia (according to PET scans). This is why when you avoid substances which cause a dopamine surge, you’re more fluent. Substances like caffeine, alcohol, sugars etc… all cause dopamine surges in our brain and for stutterers who have a dysregulated system already, it causes havoc for our speech motor controls. This is different for different stutterers though. Some find alcohol or caffeine helps with fluency, whilst for others it’s really bad. I guess it depends on your genetics and how your body metabolises these substances and also how sensitive you are to these substances. My advice is to create a journal for yourself and see what impacts your fluency and try to abstain from those things for a while to see how it affects your speech. For me, caffeine and refined carbs / sugars causes more dysfluency, especially lack of quality sleep. If I address those things, I speak a lot more fluently… almost to the point of it being unnoticeable. It’s better than doing nothing! Analyse your own situation and see what works for you. We are all different. What might work for me might not work for others. Take a step back and think about what impacts your fluency the most. My guess is it’s something that causes dopamine to go nuts in your brain, and this is causing your speech motor controls to go crazy and out of sync.