Correct - most stutterers have a hyperactive dopaminergic system in the basal ganglia, striatum and other areas in the speech motor neural networks. That’s why those antipsychotic meds which reduce dopamine help them reach fluency. However, there’s a subset of stutterers who have ADHD, which presents as an underactive dopaminergic system. In those people, meds which boost dopamine help them achieve fluency. Abilify is an interesting medication as it’s not really a dopamine antagonist or agonist, but a dopamine modulator. It either raises or reduces depending on what the baselines are at. Just depends on each persons neurobiological state.