I haven’t heard anyone say in 98% cases it’s from an excess of dopamine. Idk where you got that from but that is 100% false dude. Also scientists are interested in stuttering. I did a internship at Mayo Clinic and the doctor behind the deep brain stimulation lab wanted to talk to me about my stuttering and how they could make a protocol to maybe attempt deep brain stimulation as a cure. The problem is it’s impossible to replicate stuttering in a mice population. Stuttering is specific to a small group of adults, not seen in any animals. Of course scientists want to study stuttering, but it’s hard and different for every human. I don’t think there will ever be a drug that “cures” it.