On 2017 Oct 29, David Keller commented:

No placebo control, blinding or randomization, nor confidence intervals for the purported benefits

Patients with Parkinson disease (PD) are uniquely susceptible to the placebo effect due to the role of dopamine in expectation effects. Studies which do not include placebo control, double-blinding and randomization of subjects to therapy, cannot claim to provide more than anecdotal data.

Medical cannabis has been legalized in many states, but remains on Schedule 1 as an illegal drug at the national level. Because the commercial cultivation of cannabis is also illegal, most is supplied by underworld criminal sources. High levels of herbicides such as paraquat have been measured in marijuana, exposure to which is a risk factor for PD. I would insist on cannabis grown under safe legal conditions before risking exposure of PD patients to unknown levels of herbicides.

It is difficult to imagine how an intoxicant like cannabis, which impairs so many neurological functions, could reduce falls in PD patients. PD patients are also susceptible to dementia, and the long-term dementia risk of cannabis intoxication is not known.

As a clinician, I cannot at this time place any credence in these reported benefits of cannabis for the treatment of PD.

On 2017 Oct 29, David Keller commented:

No placebo control, blinding or randomization, nor confidence intervals for the purported benefits

Patients with Parkinson disease (PD) are uniquely susceptible to the placebo effect due to the role of dopamine in expectation effects. Studies which do not include placebo control, double-blinding and randomization of subjects to therapy, cannot claim to provide more than anecdotal data.

Medical cannabis has been legalized in many states, but remains on Schedule 1 as an illegal drug at the national level. Because the commercial cultivation of cannabis is also illegal, most is supplied by underworld criminal sources. High levels of herbicides such as paraquat have been measured in marijuana, exposure to which is a risk factor for PD. I would insist on cannabis grown under safe legal conditions before risking exposure of PD patients to unknown levels of herbicides.

It is difficult to imagine how an intoxicant like cannabis, which impairs so many neurological functions, could reduce falls in PD patients. PD patients are also susceptible to dementia, and the long-term dementia risk of cannabis intoxication is not known.

As a clinician, I cannot at this time place any credence in these reported benefits of cannabis for the treatment of PD.