I basically said the same thing. Once your brain makes the neural pathways for anxiety/fear, they can take over in all situations. This is an extreme example, but a military vet who gets panic attack from fireworks knows it’s not bombs - but their neural pathways do not. My theory is that debilitating stuttering comes from a combo of all these - we have a predisposition toward the mechanics of stuttering, are naturally sensitive and had a few extra bad experiences with talking as a young kid. Note - sensitive people can be angry/mean too, esp if they feel unfairly treated. With your alcohol theory, You are looking for something that I doubt exists