Major Medical Cannabis Research Published in 2018 

A lot more research is still needed.

medical research iStock /metamorworks

The potential benefits and risks of cannabis are both exciting and elusive. The body of literature concerning these issues is rapidly growing as researchers strive to match the pace of the developing cannabis industry and its expanding market. This article will provide a summary of peer-reviewed medical reviews published in 2018. 

Cannabis Promotes Overall Health 

A Biomed Research International report analyzed evidence supporting cannabis’ broad medical utility. The authors reviewed studies showcasing cannabis’ efficacy as an anti-inflammatory, anti-cancer, and antioxidative agent. Specifically, the review analyzed research showing that CBD is both palliative and anti-proliferative therapy that can attenuate the symptoms of chemotherapy as well as potentially kill certain cancer cells. This is a good option for those who are looking for an adjuvant to chemotherapy or wanting to avoid chemotherapy altogether. This is an important decision that a patient may make after a conversation with their doctor. The authors also identified studies showcasing CBD’s antioxidative effects, suggesting it could play a role in preventing cardiovascular and neurodegenerative diseases. The authors cite CBD’s non-psychoactivity as one of the cannabinoid’s advantages in that it produces therapeutic results without affecting cognitive ability. 

The endocannabinoid system (ECS) has been an increasingly important target of medical research because of its role in facilitating many physiological processes. A Drugs review confirmed the scope of the ECS’ reach, referencing its role in energy balance, appetite stimulation, pain perception, embryogenesis, memory, nausea and vomiting, blood pressure and in the progression of an array of disorders including Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, multiple sclerosis, irritable bowel syndrome, anorexia, addiction, eye disease, and cancer. Research suggests that certain cannabinoids engage the ECS in beneficial ways. The review found that existing evidence showing cannabis’ efficacy in treating these disorders is promising and merits continued investigation.  

Cannabis And Autism

Doctor pointing with pen to the brain blood vessel on the MRI image.

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There is no cure for autism spectrum disorder, but pharmaceutical medications are used to treat their comorbidities, or related symptoms. Conventional therapies come with many side effects that, while reducing the symptoms, can severely hamper the patient’s quality of life. 

Cannabis’ universally beneficial effects give it utility in the treatment of co-morbidities related to ASD including sleep disorders, ADD/ADHD, and epilepsy. A Progress in Neuro-Psychopharmacology & Biological Psychiatry report found that CBD may be a promising therapy for these symptoms of ASD. The authors argued that as of now, there are no effective treatments for ASD comorbidities due to the extensive side effects of conventional pharmaceutical drugs. While the researchers noted that there is no preclinical or clinical evidence demonstrating the efficacy or safety of CBD in the treatment of core symptoms related to ASD, they concluded that CBD “seems to be a candidate for the treatment of ASD.” The authors do, however, want to caution that the findings are so far only suggestive, and not conclusive until further research in appropriate animal models or human clinical trials can be conducted.

Cannabis And Cancer 

An Expert Opinion on Investigational Drugs review examined evidence concerning cannabis’ efficacy as a treatment for chemotherapy-induced nausea and vomiting, cancer-related pain, anorexia, insomnia, anxiety, and cancer cell proliferation.  After reviewing the evidence, the author’s conclusion was promising: the research indicating cannabis’ efficacy as a palliative therapy is strong, and the evidence suggesting cannabis’ antiproliferative effects is apparent, though limited. The authors recommended that doctors monitor patients using cannabis for palliative relief and urged for the continued research into cannabis’ antiproliferative effects. 

While there is some promising evidence regarding the palliative and antineoplastic properties of CBD, further scientific study is necessary to understand how CBD interacts with other cancer therapies a patient may want to take concurrently, such as induction/inhibition of the Cytochrome P450 enzyme system, for example.

Cannabis And Mental Illness 

Perhaps one of the most ambivalent areas of research is in the effect of cannabis on mental illnesses. A mixed bag of evidence demonstrating cannabis’ risks and benefits in this area leave patients and medical professionals with little confidence about marijuana as a treatment for certain mental disorders. 

 The International Journal of Social Psychiatry published a report analyzing research completed on humans regarding the relationship between cannabis consumption and the onset of psychosis or schizophrenia gathered in a total of 66 peer-reviewed medical papers.   The results implicated cannabis in the onset of psychosis. In fact, the evidence suggests that “cannabis use doubles the risk of developing psychosis in vulnerable people.” Existing evidence points to a correlation between age of cannabis use and the early onset of psychotic disorders. The earlier a person begins using cannabis, the earlier they may experience their first psychotic episode. 

A Life Sciences review underscored the ambivalence surrounding cannabinoids and mental health. The report analyzed the role of the ECS and cannabinoids in the pathogenesis of depression. While the authors agreed that the ECS remains a relevant research target in the continued investigation of depression, they could not conclude which depressive disorders best responded to cannabinoids based on the current evidence. 

Areas In Urgent Need Of Cannabis Research

Senior Medical Research Scientist Looking under the Microscope in the Laboratory. Neurologist Solving Puzzles of the Mind and Brain. In the Laboratory with Multiple Screens Showing MRI / CT Brain Scan Images.

iStock /gorodenkoff

Although cannabis evidence is expanding, there remain several research gaps in areas that are becoming of increasing importance including the relationship between cannabis and the following:

  • Male fertility—recent evidence suggests that the quality of semen is on the decline at the same time that couples are choosing to delay having children. In light of these findings and the rise of cannabis legalization throughout the world, a European Urology Focus report examined the evidence on cannabis’ effect on male reproduction. The extremely limited evidence “associated cannabis use with lower sperm concentrations, suggesting a negative impact on fertility potential.” 
  • Mood—most of the evidence surrounding cannabis and mood examines short term and acute effects. There is little evidence examining cannabis use and affect in daily life. A Drug and Alcohol Dependence report concluded that daily cannabis use may be associated with increased anger/hostility. The authors noted the need to consider the effect of other substances such as alcohol on these findings. In light of these mixed results, more research is definitely needed before we can draw any conclusions.
  • Pregnancy—among many other symptoms, pregnancy can cause women to experience pain, nausea and vomiting, and difficulty sleeping. Cannabis has been identified as a therapy for each of these conditions, and that may explain why the use of cannabis among pregnant women is on the rise. However, it is unclear if this use poses a danger to the fetus. A Preventative Medicine report confirmed the difficulty in synthesizing existing research in order to make clinical recommendations because of methodological issues and the challenge of interpreting existing evidence. Until further scientific evidence is able to show otherwise, it is advisable that all pregnant women avoid using cannabis products, just as they would avoid using tobacco and alcohol during pregnancy. We have plenty of data to show that alcohol and tobacco are damaging to a fetus, and while we are not yet sure about cannabis, it is advisable to err on the side of caution, given that cannabis metabolites can cross the placenta, and we don’t know how exactly they can affect a developing fetus.

The rise of legal cannabis has logically coincided with an increase in cannabis use. While recent research showcases the medical attributes of marijuana, it is imperative for public health that consumers and medical professionals stay current on cannabis research. 

This information is presented for educational purposes only and is not intended to diagnose, treat, cure or prevent any medical condition.  Please always consult your own doctor. 

Major Medical Cannabis Research Published in 2018  was last modified: by