Neurodegenerative diseases ( parkinsons, huntington’s chorea, MS )

• Alzheimer's disease.
• Amyotrophic lateral sclerosis.
• Friedreich's ataxia.
• Huntington's disease.
• Lewy body disease.
• Parkinson's disease.
• Spinal muscular atrophy.

Multiple studies on animals and clinical trials have shown neuroprotective effects of cannabinoids. ECS is a retrograde signalling system which simply put means that it works on negative feedback. If there is too much neurotransmitter release, ECS puts a check to stop it and if there is too little neurotransmitter release then ECS signals to increase it. Any derangement in the ECS can affect this feedback mechanism thereby giving rise to various illnesses. Also, CBD (cannabidiol) works though multiple allied pathways (TRPV, PPAR, etc.) to modulate signalling and prevent nerve degeneration.
Cannabinoids have a wide range of potential therapeutic application, some of which are even backed by clinical studies in the last five years.

Parkinson’s disease:

Parkinson’s disease (PD) is a common and complex neurological disorder that primarily happens due to depletion of dopamine in certain areas of the brain. This gives rise to certain peculiar symptoms which are helpful in the clinical diagnosis. The main symptoms (among others) include tremors (shaking of hands while trying to do any activity or even at rest), rigidity (unable to flex knee/ elbow during movements), loss of balance and slurred speech.

Currently the main line of treatment includes drugs that elevate dopamine levels in the brain or which increase sensitivity of dopamine receptors. However, these drugs have shown to be effective only in early stages of the illness. Even with these drugs, the disease invariably progresses and long-term use of these drugs reduce its efficacy. The non-motor symptoms like dementia, depression, anxiety, psychosis and pain doesn’t show any response to the drug treatment.

Animal studies have shown that CBD modified the dopaminergic system along with the ECS thereby increasing dopamine availability. These studies show the potential of cannabinoids in reducing motor-symptoms of PD and also prevent disease progression.

Smaller studies have shown that CBD treatment improved sleep quality, reduced psychotic symptoms, and improved quality of life in PD without any side-effects. Another small study showed that CBD did not worsen motor symptoms but it reduced the disease scoring with no adverse effects during the study period.

Only one clinical study so far has commented the positive effects of CBD in alleviating levodopa induced (medicine for PD) involuntary movements (dyskinesia).

Reference:
Rieder CR. Cannabidiol in Parkinson’s disease. Braz J Psychiatry. 2020;42:126-127. http://dx.doi.org/10.1590/1516-4446-2019-0810
Cannabidiol for the treatment of psychosis in Parkinson's disease. A W Zuardi et al. J Psychopharmacol. 2009 Nov;23(8):979-83. doi: 10.1177/0269881108096519. Epub 2008 Sep 18.
Evidence for the use of cannabinoids in Parkinson's disease. Carsten Buhmann et al. J Neural Transm (Vienna). 2019 Jul;126(7):913-924. doi: 10.1007/s00702-019-02018-8.