Cannabinoids in Animal Models of Epilepsy: CBD and CBDV Show Consistent Benefits, but THC's Effects Are Complex | Research

The takeaway

A comprehensive review of animal epilepsy research found that CBD and CBDV consistently reduced seizures, while CB1 receptor agonists (like THC) showed both anti- and pro-seizure potential depending on the model, dose, timing, and brain region involved.

Readers following the science of cannabinoids for epilepsy.

CBD and CBDV showed consistent anti-seizure effects; CB1 agonists showed both anti- and pro-seizure potential

What the researchers found

The review surveyed decades of preclinical research on plant cannabinoids in models of seizures, epilepsy, epileptogenesis (the development of epilepsy), and seizure-related neuroprotection.

In simple acute seizure models, activating CB1 receptors typically reduced seizures, and blocking them worsened seizures. However, in more complex models of chronic epilepsy, the picture became far more nuanced. Factors including the brain regions involved, the balance between excitatory and inhibitory circuits, receptor desensitization, whether the drug was a full or partial agonist, and the timing and duration of treatment all influenced whether endocannabinoid modulation was anti- or pro-epileptic.

CBD and CBDV (cannabidavarin) stood out for their more consistent anti-seizure effects across models. Two Phase III clinical trials of CBD in Dravet syndrome and Lennox-Gastaut syndrome provided pivotal evidence of efficacy. However, the molecular mechanism of CBD's anti-seizure action remained poorly understood at the time of this review.

Why it matters

This review provides essential context for the CBD-epilepsy story: while CBD's clinical benefits are becoming established, the broader endocannabinoid system's role in epilepsy is far more complex than "cannabinoids stop seizures." Understanding these complexities is important for developing next-generation treatments and for setting realistic expectations about cannabis-based epilepsy therapies.

The numbers in context

Over 100 individual plant cannabinoids identified in cannabis. Two Phase III clinical trials of CBD completed (Dravet syndrome and Lennox-Gastaut syndrome). CBD and CBDV showed the most consistent anti-seizure effects in preclinical models.

How the study worked

Comprehensive narrative review of the published literature on plant cannabinoid effects in preclinical models of seizures, epilepsy, epileptogenesis, and neuroprotection.

What this study cannot tell us

Narrative review without systematic methodology. The complexity of the preclinical literature makes synthesis difficult, as results depend heavily on the specific model, species, drug, and protocol used. Many animal models of epilepsy do not perfectly replicate human epilepsy. The review's scope is broad, necessarily sacrificing depth in some areas.

How to read the evidence

Strong evidence: comprehensive review of a large preclinical literature, bolstered by concurrent Phase III clinical trial results.

When this study was published

Published in 2017, concurrent with pivotal CBD epilepsy trials. Epidiolex was FDA-approved in 2018.

The bigger picture

The epilepsy-cannabis field underwent a paradigm shift with the completion of Phase III CBD trials. This review captures the state of knowledge at that turning point, noting both the genuine breakthrough (first controlled evidence of efficacy) and the significant gaps (unknown mechanism, unclear benefit in other epilepsy types, risks of THC-containing products in pediatric populations).

Questions still open

What is CBD's actual molecular mechanism for reducing seizures? Are there epilepsy types beyond Dravet and Lennox-Gastaut where CBD is effective? Could CBDV offer advantages over CBD for certain seizure types? What are the long-term effects of pediatric CBD use on brain development?

Common questions

Is CBD or THC better for epilepsy?

Based on the preclinical and early clinical evidence reviewed here, CBD has more consistent anti-seizure effects and lacks THC's psychoactive properties. THC-type compounds can both reduce and potentially worsen seizures depending on factors like dose, timing, and the specific brain circuits involved. CBD (as Epidiolex) is the only cannabinoid with FDA approval for epilepsy.

What is CBDV and is it useful for seizures?

CBDV (cannabidivarin) is a lesser-known cannabinoid structurally similar to CBD. In animal models, it showed consistent anti-seizure effects similar to CBD. Research into CBDV for epilepsy is less advanced than CBD research, but it represents a potential additional therapeutic option.

Read the original research

Therapeutic effects of cannabinoids in animal models of seizures, epilepsy, epileptogenesis, and epilepsy-related neuroprotection.

Epilepsy & behavior : E&B, 70(Pt B), 319-327

View on PubMed ↗Publisher’s paper ↗

Citation

Rosenberg, Evan C; Patra, Pabitra H; Whalley, Benjamin J. (2017). Therapeutic effects of cannabinoids in animal models of seizures, epilepsy, epileptogenesis, and epilepsy-related neuroprotection.. Epilepsy & behavior : E&B, 70(Pt B), 319-327. https://doi.org/10.1016/j.yebeh.2016.11.006