From Faizan Sheikh's PD website ("My Angel, My Hero")
They ask us, "where is the science?"
Well, the science is there, if they check out what is actually happening to People With Parkinson's, not just what is happening in theoretical lab science.
Cannabis and Parkinson’s: Dr. Mark Sircus’ blog:

“… some cannabinoids are potent antioxidants that can protect neurons from death even without cannabinoid receptor activation. It seems that cannabinoids can delay or even stop progressive degeneration of brain dopaminergic systems… In combination with magnesium cannabinoids represent, qualitatively, a new approach to the treatment of Parkinson’s Disease.
Dr. Evzin Ruzicka, neurologist at Charles University in Prague said, “To our knowledge, this is the first study to assess the effect of cannabis on Parkinson’s disease, and our findings suggest it may alleviate some symptoms"
39 patients (46%) reported that their Parkinson’s disease symptoms in general were relieved after they started using cannabis; 26 (31%) reported an improvement in tremor while at rest, and 38 (45%) experienced a relief of bradykinesia. Relief of muscle rigidity was reported by 32 (38%), and 12 (14%) said they had an improvement in levodopa-induced dyskinesias.
… the improvement in symptoms occurred an average of 1.7 months after they had started using cannabis. Patients who used it for at least three months were more likely to experience symptom relief than those with shorter experience….
In a 2007 study published in Nature, researchers from the Stanford University School of Medicine report that endocannabinoids, naturally occurring chemicals found in the brain that are similar to the active compounds in marijuana and hashish, helped trigger a dramatic improvement in mice with a condition similar to Parkinson’s.
Dr. Robert Malenka and Dr. Anatol Kreitzer combined a drug used to treat Parkinson’s disease (Dopamine) with an experimental compound that can boost the level of endocannabinoids in the brain. When they used the combination in mice with a condition like Parkinson’s, the mice went from being frozen in place to moving around freely in 15 minutes. "They were basically normal," Kreitzer said.
…receptors for cannabinoids are all over the brain, but they are not always activated by the naturally occurring endocannabinoids," said Malenka.”
http://blog.imva.info/medicine/parkinsons-disease