A timely topic, as I've been thinking of introducing DMT to my father with Parkinson's.
Google DMT and Parkinson's. There is some ongoing researching looking into how DMT may help. Also review how Ayahuasca is used in some cultures to treat Parkinson's.
On a related topic, my father has been microdosing mushrooms the past three years. They reduce freezing and pain for about 8 hours. Unfortunately, redosing the same day is ineffective. So, I'm looking into microdosing DMT to see whether it would offer the same symptom relief but allow for redosing.
I read somewhere that psilocybin potentially reduces the tolerance to carbidopa/levodopa (CL) and/or helps the CL to be more effective so you can lower your dose. The issue with long-term use of CL is it becomes ineffective even at high dosages. In three years by father has minimally increased his CL dosage (currently one-and-a-half 25/100 pills, 3x per day), so possibly the psilocybin is helping to keep tolerance down. Side note: the half pill of CL is replaced with the equivalent l-dopa from dopa mucuna.