Psychedelics and hallucinogens, including LSD and psilocybin, act on the 5-HT2a receptor and have a long history of spiritual and counter-cultural use. They are physiologically safe, do not cause dependence, and are being researched for treating anxiety, addictions, and depression. Ketamine, used as an anesthetic and for resistant depression, has abuse potential; while safe in overdose, it poses acute risks from intoxication and chronic use can damage the urinary tract.
Movement tasks such as walking, reaching, and dexterity tests were feasible for healthy volunteers who took psilocybin doses up to 15 mg. At 20 mg, impairments appeared in tasks that combined movement with cognitive demands, such as the Box and Block Test and Digit Symbol Substitution Test. Nausea (62% of participants) and headache (54%) were the most common adverse events; no serious adverse events occurred. Participants and physiotherapists guessed the dose correctly only about half the time, indicating adequate blinding. These results suggest that psilocybin-assisted physical rehabilitation may be safe and feasible for future trials in people with movement disorders.