Desperate parents of children with severe forms of epilepsy are starting to demand access to an unusual and experimental treatment made from marijuana.

But many doctors in Canada are saying that until there is more evidence that the treatment is actually helpful, they’re not going to be recommending it to patients.

Fifteen-year-old Teigan Janfield has suffered from severe epileptic seizures her whole life. She has a rare genetic disorder called Dravet Syndrome, also known as Severe Myoclonic Epilepsy of Infancy (SMEI), which causes her to have several seizures a day.

"It's horrible and heartbreaking to see this repeatedly,” her mother Paula Janfield told CTV News.

None of the 14 medications that have been prescribed to Teigan over her lifetime have stopped the seizures. Now, her mother is hoping to get her an experimental treatment called CBD, or cannabidiol. The drug is a liquid marijuana extract that many say helps to stop the seizures.

CBD comes from a strain of cannabis that is high in cannabidiol but low in THC, the compound in marijuana that brings on the “high” of pot-smoking. Advocates of the treatment say it calms the brain without intoxicating children.

CBD is legal for children in some U.S states, including Colorado, but parents in Canada can't get the extract because they can’t find doctors who will prescribe it.

Still, many parents in the U.S. report CBD has dramatic results. California father Jason David says he has been giving CBD to his six-year-old son Jayden, who also has Dravet Syndrome. He says Jayden has been seizure-free for nine months.

Advocates like Dr. Margaret Gedde of the Clinicians’ Institute for Cannabis Medicine say CBD can significantly change the lives of children with epilepsy.

“They can eat. They can put on weight. They can sleep,” she said. “They can actually have a normal childhood.”

But others, including neurologist and pediatric epilepsy expert at Toronto’s Hospital for Sick Children Dr. Berge Minassian, say there's little scientific proof that CBD is either safe or works.

“If any doctor had used it and seen it work, it would have been published as a case report (in a medical journal). There are is no case report in the literature,” Minassian told CTV News.

Dr. Orrin Devinsky, the director at New York University and Saint Barnabas Epilepsy Centers, says there have been some animal studies that have shown CBD reduces seizures, but he remains skeptical.

“Many therapies which start out with excitement turn out not to work,” he says.

Still, Devinsky has received approval from the FDA to begin a new study in the next few months to test the safety of CBD in children with Dravet Syndrome.

“Then, we will move into studies to see if it is effective,” he says.

The results of that research could take several years. In the meantime, many parents of kids with severe epilepsy say their children should be allowed to try the treatment on compassionate grounds because, so far, nothing else is working.

Tiegan’s mother Paula is one of those who want to access the treatment, as she worries about the effects of her daughter’s epilepsy.

“We know seizures can cause brain damage,” she says. “This is something we needed yesterday.”

Barry Pogson, whose nine-month old daughter Kate has already suffered more than 50 seizures, said CBD could offer an alternative to emergency medicines that often don’t work.

“It is scary when you run out of things to give her,” Pogson said. “It’s terrifying.”

Kate’s seizures can last up to an hour and Pogson said he worries that one of them might be fatal or that his daughter will suffer long-term brain damage.

In a statement, Health Canada said people can apply for access to marijuana for medical purposes if they meet certain criteria, and the agency has a contract with Prairie Plant Systems Inc. to produce a “reliable, standardized source” of marijuana for patients who qualify.

However, Health Canada said “while there are many anecdotal reports of the therapeutic value of marijuana, as well as different strains of marijuana, scientific evidence does not establish the safety and efficacy of cannabis to the extent required by the Food and Drug Regulations for marketed drugs in Canada.

“Therefore, it is not an approved therapeutic substance in Canada.”

The agency said new regulations will come into effect on April 1, 2014, allowing individuals to get marijuana directly from licensed producers. The new rules will not restrict those producers to any one strain of marijuana and there will be no restrictions on THC or CBD levels.

Health Canada said three prescription medications containing THC, a THC derivative or TCH with other cannabinoids have received “notice of compliance and market authorization.” Those medications are dronarbinol (Marinol), nabilone (Cesamet) and Sativex.

With a report from CTV medical specialist Avis Favaro and producer Elizabeth St. Philip