Parkinson’s disease is characterized by a deterioration of motor functions, which are often visible as tremors, rigidity, slowness of movement and/or postural instability. Tremors are the most visible and well-known of the symptoms but other symptoms of Parkinson’s disease can include a deterioration of some cognitive functions, mood disorders or behavioral disorders. People with Parkinson’s can have difficulty with concentration, memory, language and visual-spatial skills.
Since half to three-quarters of all Parkinson’s patients suffer from severe pain the cannabinoids in medical marijuana can be extremely helpful in reducing pain. In a study with 237 people with Parkinson’s disease researchers concluded that the pain caused by Parkinson’s could be reduced by using marijuana .
Exciting Advances in Research
In 2013, an Australian laboratory published a study  using the UPDRS (Unified Parkinson’s Disease Rating Scale), which measures the severity of the disease symptoms. This lab discovered that the cannabinoids in medical marijuana had a positive effect on the tremors, muscle rigidity and akinesia (loss of body movement).
Patients with an average age of 66 and who on average had been diagnosed with Parkinson's 7.5 years ago, were tested before consuming cannabis and again 30 minutes after consuming cannabis. The differences in the UPDRS scores for each of the key motor symptoms were conclusive. According to these patients, one “dose” of cannabis, i.e. one cannabis cigarette or one dose of vaporized cannabis, could provide relief for 2 to 3 hours.
Another observational study  with 22 Parkinson’s patients was done in 2014 and proved for the first time the effectiveness of cannabinoids on Parkinson’s disease motor and non-motor disorders. The researchers found that the UPDRS motor skills scores “improved significantly after cannabis consumption.” They also saw “significant improvement after cannabis treatment with tremors, rigidity and bradykinesia (slowness of body movement) as well as significant improvement of sleep and pain scores.”
No Undesirable Side Effects
Unlike with many conventional prescription drugs, all of these improvements observed with Parkinson’s sufferers who used cannabis were achieved with “no significant adverse effects” as the researchers pointed out. Since only 22 Parkinson’s patients were involved in this study they are urging that much larger, controlled studies be done to further verify these results.
While most people have never heard of Dystonia it is a neurological movement disorder characterized by abnormal muscle tension and involuntary, painful muscle contractions. It is the third most common movement disorder after Parkinson's disease and affects more than 300,000 people in North America.
Several different prescription drugs are used to treat various forms of dystonia like the benzodiazepines, baclofen, Botulinum toxin, anticholinergic agents, and tetrabenazine but these drugs simply relieve the symptoms of dystonia and in many cases the relief they provide is incomplete. These drugs typically have the unwanted side effect of making patients drowsy and may also cause muscle weakness and behavioral problems.
A 2002 case study published in The Journal of Pain and Symptom Management reported improved symptoms of dystonia in a 42-year-old patient suffering from chronic pain after he smoked cannabis.
Investigators reported the patient’s subjective pain score fell from nine to zero (on a zero-to-ten scale) following cannabis inhalation, and that he did not require any additional pain medication for the following 48 hours. The investigators concluded, "No other treatment intervention to date had resulted in such dramatic overall improvement in [the patient's] condition".
A second case study by a research team in Argentina reported “significant clinical improvement” following cannabis inhalation in a 25-year-old patient with generalized dystonia due to Wilson’s disease
A German research team reported successful treatment of musician’s dystonia in a 38-year-old professional pianist following the administration of 5 mg of THC in a placebo-controlled single-dose trial
Conclusions on cannabinoid treatment
Investigators reported “clear improvement of motor control” in the subject’s affected hand, and noted, “Two hours after THC intake, the patient was able to play technically demanding music, which had not been possible before treatment.” Prior to cannabinoid treatment, the subject had been unresponsive to standard medications and was no longer performing publicly.
“The results provide evidence that … THC intake … significantly improves [symptoms of] focal dystonia,” investigators concluded.
 Treatment For Motor And Non-Motor Symptoms In Parkinson’s Disease. An Open-Label Observational Study – MDS 17th International Congress of Parkinson’s Disease and Movement Disorders, Volume 28, June 2013 –
 2014 Mar-Apr;37(2):41-4. doi: 10.1097/WNF.0000000000000016.Cannabis (medical marijuana) treatment for motor and non-motor symptoms of Parkinson disease: an open-label observational study. 1, , , .