The results of two recent studies suggest that THC may be effective in treating epilepsy. The news comes amid numerous reports that another cannabinoid, cannabidiol (CBD), may also be a viable treatment for seizure disorders. The work of medical researchers in Canada and Australia may indicate that cannabis medications with a combination of cannabinoids may be more effective at reducing seizures than CBD alone.

Canadian Study Shows Reduction in Seizures

In a study at the Hospital for Sick Children in Toronto, researchers treated 20 children with an experimental cannabis oil medication containing CBD and THC at a ratio of 50:1. The medicine was donated by Tilray, its Canadian manufacturer that also funded the research.

All of the children have a form of drug-resistant epilepsy (DRE) known as Dravet Syndrome which can cause up to 1,000 seizures per month. The children were given small doses of the cannabis oil initially, slowly increasing the amount over several weeks. Eight of the children eventually reached the target dose specified by the study.

Neurologist Dr. Blathnaid McCoy, one of the study’s researchers, said in a release that the results were encouraging.

“We observed promising clinically beneficial effects including a reduction in seizure frequency and improvements in certain aspects of adaptive functioning and quality of life measures,” McCoy said.

The medicine was most effective in the children who reached the target dose. Overall, the higher the dose, the more effective the medication was.

“In the participants who reached the target treatment dose we saw a statistically significant reduction in motor seizures, and an increase in seizure-free days compared to those who did not reach the target dose,” McCoy said.

Many caregivers also noted an improvement in the quality of life. Most children experienced side effects including sleepiness, diarrhea, and a loss of appetite, although these improved over time.

McCoy said that the results add “to a growing body of evidence that cannabinoids can exert anti-seizure effects and are safe and tolerable in treating pediatric DRE.”

More Evidence From Australia

In another study at the University of Sydney’s Lambert Initiative for Cannabinoid Therapeutic in Australia, researchers determined that 75 percent of parents of epileptic children who used unapproved cannabis medications believe that they are effective in reducing seizures. Other benefits, including improved cognitive and language abilities, were also noted.

But contrary to expectations of most parents, most of the extracts being used only contained small amounts of CBD, according to Iain McGregor, academic director of the Lambert Initiative and one of the study’s authors.

“Although the illicit extracts we analyzed contained low doses of CBD, three in four were reported as ‘effective’, indicating the importance of researching the cannabis plant in its entirety for the treatment of epilepsy,” McGregor said. “And despite the overwhelming presence of generally low levels of THC, concentrations did not differ between samples perceived as ‘effective’ and ‘ineffective.'”

McGregor added that the most effective epilepsy treatments from cannabis may need more than THC or CBD, or even both.

“Our research indicates there is a potential role for other cannabinoids, alone or in combination with conventional drugs, in treatment-resistant epilepsy — and this warrants further investigation so we can hopefully develop safer and more effective medicines.”

Results of the study were reported in the journal Scientific Reports.