Short answer: There is no solid clinical evidence that psilocybin treats multiple sclerosis itself. A small pilot in people with advanced MS reported short term improvements in depression, anxiety, and quality of life, but it did not test effects on disease activity, motor function, pain, spasticity, or fatigue.
Preclinical work hints at neuroplastic and anti inflammatory effects, yet this has not been shown to translate into MS outcomes. Anecdotal reports exist, mainly about mood and stress, but I cannot verify claims about improvements in pain, spasticity, or disability.
If you are considering this, note the uncertain efficacy, potential risks, and legal constraints. For a brief research overview, see this working paper: summary of emerging evidence.
Bottom line: psilocybin may help mood, but there is no evidence it changes the course of MS. Hope this helps.