Cannabis is said to help with Parkinson’s disease. But can cannabis improve symptoms?
For several years, cannabis has been legally used for medicinal purposes in certain forms. How well agents perform in various applications is questionable. The reader wanted to know how cannabis helps with Parkinson’s disease.
There is hardly any research available.
We quickly completed our literature research on this issue. The benefits of cannabis for Parkinson’s disease have only been studied in two studies that meet at least some quality standards. This includes, for example, comparison with sham training and random assignment of participants to comparison groups.
Unfortunately, it is impossible to answer whether the research is really meaningful: the publications lack details that are important for our assessment.
Too few test subjects.
In addition to the missing information, there are other fundamental problems: only 40 people participated in the research. There are too few of them to make reliable statements.
In addition, two studies examined patients with Parkinson’s disease at different stages of the disease, tested very different cannabis preparations and their effect on different complaints, such as different types of movement disorders. This significantly limits the comparability of studies.
Effective? We do not know.
However, the results were not what the cannabis advocates had hoped: One study found no difference in effectiveness between cannabis and the fictitious drug when it came to “dyskinesis,” the involuntary movement that affects many people with advanced Parkinson’s disease.
In another study, cannabis also failed to relieve various movement disorders typical of Parkinson’s, such as walking or standing up, better than a placebo.
However, according to the research team, there were signs of little improvement from cannabis in terms of quality of life. However, it is relatively unclear whether this effect actually exists, and it is unclear whether patients actually perceive the improvement as such.
So it’s unclear if cannabis is beneficial for Parkinson’s disease.
What about the possible side effects? How well people with Parkinson’s tolerate cannabis cannot be said for sure due to the small number of participants. According to the group of authors, none of the studies found serious side effects. However, this is not discussed further. Therefore, when it comes to side effects, we need more and better research.
One study provides slightly more accurate information on side effects. Notably, psychological side effects, such as drowsiness or trouble concentrating, occurred more frequently with cannabis than with the dummy drug.
When dopamine is absent?
With Parkinson’s disease, nerve cells in the brain die that produce dopamine, a transmitting substance. Dopamine is critical to controlling movement. Therefore, various movement disorders are a typical symptom of Parkinson’s disease.
Result: Movements such as walking are slowed down, muscles are tense and typical tremors occur, mainly in the arms. These complaints have given Parkinson’s disease the popular name “tremor palsy.”
Parkinson’s disease is mainly treated with drugs that replace or make dopamine more effective. However, as the disease progresses, it often happens, for example, that the drug stops working in the same way.
Cannabis as a medicine.
In some countries, medicinal products made from cannabis, its components (cannabinoids) or chemically related substances are allowed. This includes a compound made from two different cannabis extracts that can be used to treat seizure symptoms in people with multiple sclerosis.
A drug containing the artificially produced cannabinoid nabilone is used to treat nausea and vomiting in cancer patients when other drugs have failed.
Pharmacies use a doctor’s prescription to prepare customized medicines from THC (tetrahydrocannabinol), which is the pure substance of cannabis.
Details about research.
We were able to identify two studies on the benefits of cannabis for Parkinson’s disease in which patients were randomly given a cannabis drug or a bogus drug.
In one study, participants received both treatments one after the other (“crossover”). Each phase lasted four weeks with a two-week break in between.
In another study, participants were treated with only one of the options for six weeks: that is, one of two doses of cannabis or a dummy drug.
An important problem in both studies is that the description is missing many details that would be necessary for a reliable assessment of methodological quality. Unfortunately, there are also many central points (for example, the reliability of the random distribution of groups, information about all medications taken) that can significantly affect the informativeness of examinations. Therefore, we must look at the results with great care.
Small number of participants.
The number of patients treated was rather small – 19 for the first group and 21 for the second, respectively. This can easily lead to random conclusions and does not lead to more general results that can be passed on to other patients with Parkinson’s. Thus, the informative value of the research is very limited.
Participants in the two studies also differed greatly: one study included only patients with advanced Parkinson’s disease. They suffered from this disease for about 14 years and for several years suffered from the so-called dyskinesia. These are involuntary movements that can occur during the course of illness or during therapy.
Another study involved people with Parkinson’s disease who had been diagnosed with the disease about seven to ten years ago. The publication does not provide any information on complications that existed at the beginning of the study (eg, uneven drug action, dyskinesia). Compared to another study, the participants were about ten years younger.
Various drugs and tests.
Two studies tested very different cannabis preparations: one study used a standardized cannabis extract with fixed amounts of the ingredients tetrahydrocannabinol (THC) and cannabidiol (CBD). Another study used cannabidiol alone at a dose of 75 or 300 mg per day. It also makes it difficult to compare results.
Finally, the studies also looked at very different aspects: the study of patients with advanced disease was essentially devoted to the desired relief of dyskinesia. It is not possible to assess with certainty how appropriate the questionnaire used primarily was. In any case, there is no difference in effectiveness between cannabis extract and bogus drug for any of the aspects considered.
Another study examined the effects of cannabis on all forms of Parkinson’s typical movement disorders and quality of life. For this, well-proven questionnaires were used. However, the research team was unable to determine any difference in the effectiveness of cannabis extracts and placebo for movement disorders.
In terms of quality of life, the positive impact on quality of life can be determined purely mathematically. However, it cannot be said for sure whether it is so great that it is actually noticeable as a positive change for patients.