Updated: Oct 23
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Welcome to Higher Learning LV's Study Summary series. This series reviews and summarizes peer-reviewed research studies and was developed specifically for cannabis industry professionals. These study summaries provide easily digested quick reads for a variety of important issues regarding the commerce and chemistry of legal cannabis.
A 2018 study entitled "Epilepsy and Cannabis: A Literature Review" that was published in the Cureus Journal of Medical Science investigated the potential medicinal benefits of cannabis for epilepsy, noting that "the off-label use of cannabis sativa plant in treating seizures is known since ancient times."
Cureus Journal of Medical Science
The study was designed as a literature review that examined the results of previous studies on the topic published between 1978 and 2017. "Major search engines used were PubMed and Google Scholar," reported the study's authors. "We used keywords such as cannabis, epilepsy, and randomized control trials. We restricted our data collection to randomized control trials," they noted.
The study explored the ability of the "active ingredients" produced by cannabis, delta-9 tetrahydrocannabinol (THC) and cannabidiol (CBD). The study's authors described CBD as "safer and more effective in treating seizures [than THC], with less adverse psychotropic effects."
"Approximately one-third of patients with epilepsy have seizures that are resistant to [traditional] anti-epileptic medications," reported the study.
"Epilepsy is one of the most common non-communicable neurological diseases," reported the study. "Approximately one-third of patients with epilepsy have seizures that are resistant to [traditional] anti-epileptic medications," it noted. "Drug-resistant epilepsy" was defined by the study's authors as cases where "seizures cannot be controlled, even after using the appropriate dose of at least two anti-epileptic medications."
The study reported that cannabis has been employed to treat conditions such as anorexia, epilepsy, and pain "since ancient times." It identified CBD and THC as the "most abundant" phytocannabinoids produced by the cannabis plant.
The researchers cited clinical trials involving humans and the cannabinoid CBDV as an anticonvulsant drug. They also noted that THC "has many psychiatric side effects," making CBD a more promising candidate for seizure control and overall treatment of epilepsy (especially among children).
The study noted a 1978 double-blind clinical trial involving pioneering Israeli endocannabinoid system researcher Raphael Mechoulam. Nine patients with treatment-resistant epilepsy were involved in the study, with four of these participants "randomly assigned in the CBD group" and the remaining five receiving a placebo.
Those who received actual CBD were given 200 mg daily for three months. "Two of the epilepsy patients had no seizures during the entire three months of treatment," reported the researchers. The third experienced "partial improvement" and the fourth demonstrated "no improvement." None of the study participants experienced toxicity from the CBD.
"Four of the patients who received CBD were seizure-free, with three experiencing 'partial improvement' and one exhibiting no effect."
Another double-blind clinical trial, this one conducted in 1980, involved 15 participants, all of whom suffered from "secondary generalized epilepsy with a temporal focus." Eight of these participants were given CBD (200-300 mg per day for eight to 18 weeks) and seven were given a placebo.
Participants were tested via electroencephalography and electrocardiography at an interval of between 15 and 30 days. Four of the patients who received CBD became seizure-free, with three experiencing "partial improvement" and one exhibiting no effect.
The CBD molecule
However, not all clinical trials cited demonstrated positive efficacy (seizure reduction) for study participants. For example, one study involving 12 "institutionalized patients with uncontrolled seizures" treated six with CBD (300 mg for one week and 200 mg for the following three weeks) and the other half with a placebo. "No difference in the seizure frequency was reported," concluded the authors.
Another study cited involved 137 participants who were treated "with 2–5 mg/kg of CBD per day, which was titrated up to 50 mg/kg/day for a period of 12 weeks." This investigation observed a reduction in monthly seizure frequency in the group receiving CBD of 37 percent, "with the greatest reduction recorded in patients with atonic and focal seizures." This study noted adverse effects of the CBD in some of the participants that included "somnolence, decreased appetite, diarrhea, fatigue, and convulsions."
This study noted some "adverse effects" of the CBD, including "somnolence, decreased appetite, diarrhea, fatigue, and convulsions."
A 2017 study involved 120 children and young adults with Dravet syndrome and drug-resistant epilepsy who received "20 mg/kg/day for a period of 14 weeks." It found that the frequency of seizures decreased for both the treatment group and the placebo patients. 43 percent of participants receiving CBD experienced a seizure decrease of greater than 50 percent, while 27 percent of the placebo group achieved the same.
The good news: "In the treatment group, five percent of the patients became seizure-free during treatment," observed the study's authors. However, the scientists also noted that 75 percent of the patients in the treatment group "faced adverse effects such as diarrhea, vomiting, fatigue, pyrexia, and somnolence," with somnolence the most common.
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The study pointed out many of the shortcomings of the previous research that it investigated. "Many of [the clinical trials] until 2016 were carried out over a short duration of three to four months and remained underpowered, with the maximum sample size of 15 patients," concluded the study.
"Some studies cited displayed distinct improvements in the participants via decreased average seizure activity, while multiple other studies observed no improvement in patients consuming CBD."
Overall, this literature review revealed mixed results. Some studies cited displayed distinct improvements in the participants via decreased seizure activity, while multiple other studies observed no improvement in patients consuming CBD. Several studies reported adverse effects among patients, including diarrhea, vomiting, and fatigue.
The study's authors concluded that there is "an increasing interest in developing cannabis preparations for the treatment of drug-resistant epilepsy" because they may offer more efficacy with fewer side effects than traditional anti-epileptic medications. "We encourage research in this area...to help decrease the morbidity and mortality associated with drug-resistant epilepsy," noted the scientists.
View the original study.