Risperidone and olanzapine have anxiolytic and sedating properties. I don't think sufficient evidence has been presented to distinguish the effects of the perceived improvement in stuttering from reduction of anxiety/sedation vs. theoretical improvement from dopamine antagonism. I mean, CBT can help with alleviating stuttering and result in subjective improvement. It doesn't mean anxiety is the pathological mechanism of stuttering. The quality of evidence for the published RCTs for pharmacotherapy of stuttering, is almost entirely weak or very weak, being hampered by small participant numbers, methodological issues, incomplete blinding, conflicting conclusions with statistical results or, in the case of the first trial with ecopipam, major issues with loss to follow-up - of the 10 participants, 2 were excluded from final analysis as they were twins, then 3 were lost to follow-up (therefore 50% retention). This is a major red flag. And going back to the early 2000s, if you look at the data from Maguire's RCT on risperidone on stuttering, the confidence intervals between the intervention arm and control overlap for all primary outcome measures..