Pot offers hope for patients suffering from Parkinson’s disease. So say the results of an observational trial published in the March/April edition of the scientific journal Clinical Neuropharmacology.
Investigators at Tel Aviv University’s Rabin Medical Center in Israel assessed the impact of inhaled cannabis on patients with Parkinson’s -- a progressive disorder of the central nervous system that results in tremor, slowed movement and muscle rigidity. Researchers monitored disease symptoms in 22 patients (13 men, nine women) at baseline and then again 30 minutes after smoking cannabis. The mean age of patients enrolled in the study was 65. 
Scientists reported that inhaling whole-plant cannabis led to “significant improvement” in subjects’ disease symptoms, including decreased severity of tremor, rigidity, and bradykinsea (slowness of movement). Subjects also experienced significant improvement of sleep and pain scores. No significant adverse effects of the drug were observed, researchers reported.
Despite anecdotal reports indicating that cannabinoids may be therapeutic in the treatment PD and other related movement disorders (such as Huntington’s disease), a keyword search on the National Library of Medicine’s PubMed database yields few clinical papers on the subject. According to the results of an anonymous 2004 survey published in the journal Movement Disorders, an estimated 25 percent of PD patients have experimented with the plant and that nearly half of them reported some subjective improvement of motor symptoms. By contrast, a placebo-controlled study assessing the oral administration of a cannabinoid agonist in six PD patients reported no objective improvement in dyskinesia (involuntary muscle movements).
Israeli researchers acknowledged that their trial was the first to report the efficacy of cannabis in PD patients in a controlled setting. They concluded: “[T]his observational study is the first to report an amelioration of both motor and non–motor symptoms in patients with PD treated with cannabis. The study opens new venues for treatment strategies in PD especially in patients refractory to current medications. It may promote legalization of cannabis in other countries and should encourage pharmaceutical companies to conduct controlled studies with a more purified substance.”
In recent years, Israeli researchers have conducted similar observational trials documenting the safety and efficacy of inhaled cannabis in patients with a variety of diseases, including Crohn’s disease and cancer
The Israeli government initially permitted the medical use of cannabis for research purposes in the 1990s, but only formalized regulations in 2012 allowing for the Ministry of Health to oversee the licensed production and distribution of medicinal cannabis.