Interesting. Psilocybin is converted in the body to psilocin, which primarily acts on serotonin 5-HT2A receptors. Stuttering has been linked to dopamine system hyperactivity in the striatum and reduced cortical control. By modulating serotonin, psilocybin can indirectly affect dopamine release and cortical connectivity, which in theory could either smooth motor control of speech or, in some cases, increase anxiety if not well tolerated. Everyone’s brain is wired differently, so what might work for some might not work for others.