A significant number of epilepsy patients turn to nonmedical cannabis for seizure control, often without their physician's knowledge, new research shows.
"It's well-accepted that CBD is antiseizure, but THC and other compounds of cannabis, not so much. Actually, a lot of the literature seems to indicate that THC is more pro-convulsant, so depending on what type of cannabis patients take, they be doing more harm than good," study investigator Jimmy Li, MD, with the University of Montreal, Canada, told Medscape Medical News.
That said, he noted that self-reported data suggest nonmedical cannabis does appear to help with seizure control as well as with cognition, sleep, mood, and anxiety.
The findings were published in Frontiers in Neurology and were presented at the American Academy of Neurology (AAN) 2023 Annual Meeting.
There is growing interest in the use of cannabis for epilepsy, although medical cannabis may not be readily available, Li explained.
The researchers conducted a scoping review of the literature on the use of nonmedical cannabis (NMC) by people with epilepsy (PWE). They focused primarily on the patients' lived experience, habits, and beliefs.
They screened 3228 records from four databases, including OVID Medline, OVID Embase, Ovid APA PsycInfo, and Web of Science. The analysis included 66 studies. Of these, 45 included mostly adult epilepsy patients, and 21 included mainly pediatric patients.
Of the 13 studies reporting epilepsy type, four involved patients with predominantly generalized-onset epilepsy, and eight had patients with predominantly focal-onset epilepsy. All pediatric studies included children with epileptic encephalopathies in variable proportions.
Across the studies included in the review, the median number of PWE using NMC was 24.5. The lifetime prevalence of NMC use by PWE was highly variable, ranging from 0.69% to 76.8%.
The main type of NMC that was used varied between pediatric and adult studies. Children mostly used oral CBD extracts, whereas adults used NMC with various CBD-THC compositions. The route of administration by adults was much more varied, although smoking seemed to be the predominant route.
Li said the literature on NMC use by PWE can be characterized as "sparse and heterogeneous," mostly consisting of small, cross-sectional studies with diverse aims and outcome measures.
Few relevant studies were published before the year 2000, and no relevant pediatric studies were published before 2010, which may reflect how interest in cannabis use by children is more recent.
Studies of NMC in PWE are mostly from Western countries. There are significant gaps in knowledge about NMC use by PWE from African, Middle Eastern, Central/Southern American, and Asian countries.
In terms of demographics, studies in adults suggest that young men with epilepsy are most apt to use NMC.
There is no literature that focuses specifically on NMC use by elderly PWE, and this represents a "major knowledge gap, especially given the high prevalence of epilepsy in the elderly and the effects of cannabis on cognition," the investigators note.
The education level, comorbidities, socioeconomic standing, and marital status of PWE who use NMC were rarely explored in the studies assessed.
However, some studies suggest associations between cannabis use by PWE and lower levels of education, psychiatric comorbidities, lower socioeconomic standing, and being single. Confirming these associations would require larger, more robust epidemiologic studies.
The data on use of antiseizure medication (ASM) is heterogeneously reported. How many failed ASMs were used before NMC was tried, which ASMs are most often taken with NMC, and how the use of other ASMs evolve once NMC is begun are all open questions, the researchers report.
The data also suggest that many PWE learn about cannabis for epilepsy from nonmedical sources, including social media and the internet. The majority of PWE across all studies believed that NMC aided in seizure control as well as in cognition, sleep, mood, and anxiety.
Li said it's clear from the literature that many PWE do not disclose their NMC use to their physician. Feelings of stigma or of being unsupported by physicians are often cited as barriers to disclosure.
Ask About Cannabis Use
In an interview with Medscape Medical News, Kevin E. Chapman, MD, pediatric neurology specialist at Phoenix Children's Hospital, Arizona, noted that families may try over-the-counter cannabis/CBD products when a child's seizures are difficult to control. The same goes for adults.
"Yet, what's listed on the product label may not be what's actually in the bottle," said Chapman, member at large of the American Epilepsy Society Board of Directors, who wasn't involved in the study.
Chapman said he's had patients tell him they're using a CBD product, "and when they show me the bottle, it's, like, 50% THC to 2% CBD."
He also worries that "families may not let us know that they're taking one of those products, and then if they start having side effects, it's sometimes difficult to know what's causing it.
"For example, if the child is sleepier, is it because they're taking some kind of nonmedical cannabis product or because there's certain side effects of the medication that I'm prescribing?
"It's important to ask about all supplements that patients are taking, because there can be drug interactions. That's especially true for patients with epilepsy," Chapman added.
The study had no specific funding. Li and Chapman have disclosed no relevant financial relationships.
American Academy of Neurology (AAN) 2023 Annual Meeting: Poster 01-008. Presented April 23, 2023.
Front Neurol. Published online March 6, 2023. Full text
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Cite this: Nonmedical Cannabis Use Common in Patients With Epilepsy - Medscape - May 09, 2023.