Low-dose THC plus CBD helped seizures in Dravet mice, but chronic combination increased mortality
In a Dravet syndrome mouse model, low-dose THC was anticonvulsant and enhanced by sub-threshold CBD for heat-induced seizures, but chronic combined CBD and THC unexpectedly increased seizure severity and mortality.
Quick Facts
What This Study Found
CBD (100 mg/kg) alone was anticonvulsant against heat-induced seizures. Low-dose THC (0.1 and 0.3 mg/kg) was also anticonvulsant, but higher doses were not. A sub-threshold dose of CBD (12 mg/kg) enhanced THC's anticonvulsant effect. However, when CBD and THC were given together chronically, spontaneous seizure severity and mortality increased, a surprising and concerning finding.
Key Numbers
CBD anticonvulsant at 100 mg/kg. THC anticonvulsant at 0.1 and 0.3 mg/kg. Sub-threshold CBD (12 mg/kg) enhanced THC effect. Chronic co-administration increased seizure severity and mortality.
How They Did This
Preclinical study using Scn1a+/- mice (Dravet syndrome model). Tested CBD and THC alone and combined on heat-induced seizures, spontaneous seizures, and premature mortality.
Why This Research Matters
Many cannabis products marketed for epilepsy contain both THC and CBD. This study suggests that while acute low-dose combinations may help, chronic use of the combination could be harmful.
The Bigger Picture
The divergence between acute benefit and chronic harm from CBD+THC combinations is a critical finding for the medical cannabis community, where combined products are common.
What This Study Doesn't Tell Us
Mouse model; results may not translate to humans. Doses used are relative to mouse physiology. Mechanisms of chronic harm were not fully elucidated.
Questions This Raises
- ?Does chronic CBD+THC combination cause problems in human epilepsy patients?
- ?Are there safe ratios or dosing schedules that avoid the chronic mortality increase?
Trust & Context
- Key Stat:
- Chronic CBD+THC combination increased mortality in Dravet mice
- Evidence Grade:
- Well-designed preclinical study in a validated disease model, but animal data that need human confirmation.
- Study Age:
- 2020 preclinical study.
- Original Title:
- Interactions between cannabidiol and Δ9 -tetrahydrocannabinol in modulating seizure susceptibility and survival in a mouse model of Dravet syndrome.
- Published In:
- British journal of pharmacology, 177(18), 4261-4274 (2020)
- Authors:
- Anderson, Lyndsey L(10), Low, Ivan K(2), McGregor, Iain S(55), Arnold, Jonathon C
- Database ID:
- RTHC-02388
Evidence Hierarchy
Tests effects in animals (usually mice or rats), not humans.
What do these levels mean? →Frequently Asked Questions
Should epilepsy patients use cannabis products with both THC and CBD?
This mouse study found that while acute low-dose combinations helped seizures, chronic combined use increased seizure severity and mortality, raising concerns about long-term use of combined products.
Does THC help or hurt seizures?
In this Dravet model, very low doses of THC were anticonvulsant, but higher doses were not. The effect was enhanced by sub-threshold CBD, suggesting dose is critical.
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Cite This Study
https://rethinkthc.com/research/RTHC-02388APA
Anderson, Lyndsey L; Low, Ivan K; McGregor, Iain S; Arnold, Jonathon C. (2020). Interactions between cannabidiol and Δ9 -tetrahydrocannabinol in modulating seizure susceptibility and survival in a mouse model of Dravet syndrome.. British journal of pharmacology, 177(18), 4261-4274. https://doi.org/10.1111/bph.15181
MLA
Anderson, Lyndsey L, et al. "Interactions between cannabidiol and Δ9 -tetrahydrocannabinol in modulating seizure susceptibility and survival in a mouse model of Dravet syndrome.." British journal of pharmacology, 2020. https://doi.org/10.1111/bph.15181
RethinkTHC
RethinkTHC Research Database. "Interactions between cannabidiol and Δ9 -tetrahydrocannabino..." RTHC-02388. Retrieved from https://rethinkthc.com/research/anderson-2020-interactions-between-cannabidiol-and
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.