cbd and parkinson’s research

Cbd and parkinson's research

Parkinson’s disease can impact cognitive function and memory, particularly in those whose symptoms progress to Parkinson’s disease dementia. Because of this, medical marijuana with both THC and CBD may not be recommended, as it can impair thinking and brain function even more so. CBD by itself may be a safer route.

In some cases, people suffering from Parkinson’s disease may also have symptoms of psychosis, ranging in hallucinations to vivid dreams and illusions. Research has found that CBD may be able to help. In research out of University of São Paulo in Brazil, patients were given a dose of CBD starting out at 150 milligrams (mg) per day in addition to their current treatment plan of therapy for four weeks. The use of CBD showed no adverse effects, no impact on worsening motor function, and a decrease in their reported psychosis symptoms, meaning that not only can it help with the physical setbacks of Parkinson’s disease, it can also play a part in the cognitive challenges as well. This was however an older study and current clinical trial evidence to support the use of CBD is minimal.

CBD has been discovered as an effective way to help treat Parkinson’s disease symptoms because it interacts with two cannabinoid receptors in the body found on certain cells called CB1 and CB2. By interacting with one or both of these receptors, CBD may delay tremor development as well as have protective neurological benefits. But as seen with the above studies, there is no uniform approach or conclusion on this treatment method. This means that patients may react differently to using CBD, some having tremendous success while others seeing little difference. But regardless of whether or not CBD is an effective treatment option for you, you always need to consult your treating physician to make sure this treatment will not cause side effects.

Uses and Safety

What can cause side effects is if a patient decides to mix medical marijuana with their treatment plan that consists of certain prescription medications. If you plan to use medical marijuana as opposed to CBD by itself, it’s smart to consult a healthcare provider or your pharmacist before you start mixing it in with other medications to make sure it's safe for you.

More research out of Brazil suggests CBD can improve the overall quality of life of those with Parkinson’s disease. In a sample of 21 patients, those who were treated with 75 mg to 300 mg of CBD per day reported a significant increase in quality of life, though no significant differences were noted in motor and general symptoms or neuroprotective effects. This goes to show how much results can vary when it comes to the effects of CBD, requiring larger studies to be done in order to get more definitive answers to this treatment option.

In connection with Parkinson’s disease as well as other movement-related disorders, CBD may help improve motor skills. In one study published in Frontiers in Pharmacology CBD was shown to have a more preventative role in delaying abnormal movement symptoms in animal models of Parkinson's.  

Research

With the legalization of medical marijuana, many states are approving the use of it in a non-traditional way to treat the symptoms of certain conditions, including Parkinson’s disease. Marijuana has two major components to it—tetrahydrocannabinol (THC) and cannabidiol (CBD). Both may help with nausea and muscle pain or spasms, but unlike THC, CBD doesn’t give you the “high” feeling marijuana is most commonly known for. This makes it an enticing, natural way for many to help treat their Parkinson’s disease symptoms. What’s more, is that because CBD is a natural compound from the Cannabis sativa plant, using it may also leave you side effect-free, unlike many prescription medications.

While the research on CBD to treat Parkinson’s disease symptoms is largely inconclusive, its mild effect on patients as a whole makes it enticing to try in addition to an existing traditional treatment plan. Parkinson’s disease has no cure. But with prescription medication, therapy, and now perhaps the use of nontraditional options like CBD, patients may be able to experience less frequency and severity of symptoms that affect their motor skills.

There is a clear need for therapies that target other pharmacological systems. A multimodal approach combining activity on dopaminergic as well as non-dopaminergic system would be very helpful and needs to be explored.

Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil, Irmandade da Santa Casa de Misericórdia de Porto Alegre (ISCMPA), Porto Alegre, RS, Brazil

Although clinical diagnosis relies on the presence of cardinal motor features, PD is also associated with numerous non-motor symptoms that can be equally disabling than the motor symptoms or even more so. Drugs that enhance intracerebral dopamine concentrations or stimulate dopamine receptors remain the main treatment for motor symptoms. None of available treatments have proven to be neuroprotective or disease-modifying. Dopaminergic drugs are particularly effective during the early stages of the disease. However, PD invariably progresses, and long-term use of these medications may lead to reduced drug efficacy and the development of complications such as motor fluctuations and dyskinesias.

Parkinson’s disease (PD) is a common and complex neurological disorder that encompasses a range of clinical, epidemiological, and genetic subtypes. Loss of dopaminergic neurons in the substantia nigra leading to striatal dopamine depletion is the core mechanism underlying the cardinal motor features of PD. Although depletion of dopamine is the most notable neurotransmitter change in PD, other neurochemical changes occur and contribute to PD symptomatology. Many regions of the nervous system outside the basal ganglia are also involved in PD. The underlying molecular pathogenesis involves multiple pathways and mechanisms, such as α-synuclein proteostasis, mitochondrial function, oxidative stress, calcium homeostasis, axonal transport, and neuroinflammation.

In this issue of the Brazilian Journal of Psychiatry, a research group from Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brazil, addressed animal and human clinical studies involving the use of CBD for PD.1 The authors discussed the biological bases for a potential effect of CBD in this setting, as well as preclinical and clinical studies of CBD in PD. The latter, all conducted by their group, are an open-label study,2 a case series,3 and a randomized controlled trial.4 The open-label pilot study was conducted with six PD patients with psychotic symptoms, lasting at least 3 months before study entry, that could not be controlled by reduction of antiparkinsonian medications.2 Oral CBD doses ranging from 150-400 mg/day, combined with classic antiparkinsonian agents, reduced psychotic symptoms evaluated by different scales (the Brief Psychiatric Rating Scale and the Parkinson Psychosis Questionnaire), with no influence on cognitive and motor signs and no severe side effects. The second study was a case series of four PD patients with REM sleep behavior disorder (RBD).3 All had prompt, substantial, and persistent reductions in he frequency of RBD after CBD treatment. After drug discontinuation, the complex movements of RBD returned with baseline frequency and intensity. The third study was an exploratory double-blind trial of CBD versus placebo.4 Twenty-one PD patients without dementia or comorbid psychiatric conditions were assigned to three groups of seven subjects each who were treated with placebo, CBD 75 mg/day, or CBD 300 mg/day. Participants were assessed with respect to motor and general symptoms score (Unified Parkinson’s Disease Rating Scale [UPDRS]) and well-being and quality of life (Parkinson’s Disease Questionnaire [PDQ-39]). There were no differences across groups in motor score. However, the groups treated with CBD 300 mg/day had significantly different mean total scores in the PDQ-39. The authors point to a possible effect of CBD in improving measures related to quality of life in PD patients without psychiatric comorbidities.

There has been interest in cannabidiol (CBD) as a treatment option for PD because of the identification of multiple potential targets of action in the CNS. CBD is one of the many cannabinoids identified in Cannabis sativa, being the second most abundant constituent after Δ9-tetrahydrocannabinol (THC). Unlike THC, CBD is non-psychoactive, and has been ascribed many potential medical benefits.

All of these studies showed interesting results, but sample sizes were very small and the duration of follow-up was very short. The Movement Disorder Society Evidence-Based Medicine Committee recommendations for treatments of PD published in 2018 concluded that there was insufficient evidence to support the use of CBD for the treatment of PD at the time.5