Existing evidence on the efficacy of medical marjiuana remains largely inconclusive. EGGROLE/CC FLICKR

The seizures started in 1959, when Terrance Parker was four years old.

‘Grand mals,’ they were called — a term that rose to prominence in the late nineteenth century and loosely translates to ‘a great evil.’

He could tell when they were about to happen. The hairs on the nape of his neck prickled in anticipation. A fear of the known, it was unlike any other, yet he could do little to prevent it.

As the electrical storm raced in his brain, his limbs jerked violently and his consciousness shredded. He would later be placed on an anticonvulsant therapy, and go through medications such as Dilantin, Mysoline, and Librium with little success.

The lobectomies, first performed at the Hospital for Sick Children, or SickKids, at age 14, and then 16, failed to effectively improve his symptoms. Parker’s prognosis appeared bleak.

At least, it did until he was introduced to cannabis by a worker at the Lakeshore Psychiatric Hospital. He would smoke a joint to get high and receive immediate, albeit brief, relief from the havoc that the seizures wreaked on his body. As he continued to smoke, however, something curious happened.

The seizures stopped.

“After 38 years of this terrible affliction, and hundreds, if not more than a thousand seizures, I can say that it is only with the assistance of marijuana that I have ever been able to fight through the [fear] and stave off an oncoming grand mal,” stated Parker, in a 1997 affidavit after he was arrested for the possession and trafficking of cannabis.

Parker was acquitted of all charges in 2000, after the judge declared his arrest unconstitutional on the grounds that it violated his rights to life, liberty, and security. It was at that moment that Terrance Parker became the first individual in Canada to use marijuana legally, for medical reasons. Regulated medical cannabis later became legal in 2001.

There are many individuals with stories like that of Parker — of discovering hope in this herbaceous flowering plant.

Although controlled clinical trials that determine a direct causal relationship between the use of cannabis and the frequency of seizures have been few and far between, there is mounting anecdotal evidence of its efficacy in treating epilepsy.

Exposure to cannabidiol (CBD), a non-psychoactive component in marijuana, has been linked to the reduction of seizure frequency in pediatric epilepsy and Lennox-Gastaut syndrome, a form of severe childhood-onset epilepsy.

Despite evidence being mainly anecdotal, Dr. David Juurlink, Head of Clinical Pharmacology and Toxicology at Sunnybrook Hospital and Professor in the Faculty of Medicine at U of T, believes a case can be made for the judicious prescription of cannabis.

According to Juurlink, cannabis is particularly useful for patients whose symptoms have improved with its use. It should be prescribed on a case-by-case basis, while also considering other drugs with similar effects.

Meanwhile, high-quality scientific evidence for the therapeutic effects of cannabis in the treatment of symptoms associated with multiple sclerosis (MS) like chronic pain, neuropathic pain, and spasticity — the tightness and stiffness of muscles preventing normal movement — has been well established.

In a 2007 study published in the European Journal of Neurology, 124 individuals with MS and spasticity were given a cannabis-based medicine containing CBD and the primary psychoactive component tetrahydrocannabinol (THC), while 65 individuals were given a placebo for a duration of six weeks. The results of this research gave cannabis the green light.

Studies published in 2004 and 2006 in the Multiple Sclerosis Journal had also found similar results, confirming the growing optimism that cannabis can be used to relieve symptoms associated with MS.

In a 2009 Nature study, researchers used similar methodologies to study the effects of cannabis for neuropathic pain in patients with HIV. The researchers found that the 28 subjects, who completed both placebo and cannabis treatments, experienced greater pain relief when they were treated with cannabis.

But despite what a quick Google search might tell you, cannabis is not a panacea for all diseases and disorders.

Dr. Tony George, Chief of Addictions at the Centre for Addiction and Mental Health and also Professor in the Department of Psychiatry, found that THC in marijuana actually worsens symptoms of psychosis in patients with schizophrenia, and could induce psychosis in those who have a family history of the disorder.

Surprisingly, isolating certain cannabinoids may have the opposite effect.

“CBD seems to oppose the effects of THC… and [CBD] is being studied for anti-psychotic, anti-depressant, and anti-addictive, and cognitive enhancing effects,” said George. “If that’s true, that could be a very exciting breakthrough in therapeutics in psychiatry, and it may be a potential pain strategy.”

Currently, there is simply not enough evidence to conclude that cannabis can effectively treat a myriad of mood disorders and other debilitating diseases. It has only been proven for a few diseases, and often in isolated cases.

According to George, thus far, there are only indications that cannabinoids have positive effects on post-traumatic stress disorder, anxiety, depression, or glaucoma, and evidence to support these indications is not substantive.

Yet, preliminary research is promising and may pave the way for its unrestricted use.

With the impending legalization of recreational cannabis, however, there are some concerns over what will become of Health Canada’s Access to Cannabis for Medical Purposes Regulations (ACMPR), which replaced Marihuana for Medical Purposes Regulations in August 2016. According to Health Canada, ACMPR allows registrants to access marijuana for medical purposes and “to produce a limited amount of cannabis for their own medical purposes or to designate someone to produce it for them.”

“The problem is that the current approach by the government is sort of full speed ahead, without doing the due diligence to find out the facts,” said George.

As of March 2018, 296,702 individuals were registered with licensed medical marijuana producers under Health Canada’s ACMPR, a 70 per cent increase from the 174,503 registrants in April 2017.

“I don’t know what the future of medical marijuana is, but if you’re someone who is a patient or family member, or a healthcare professional that’s invested in that, I think there is some reason to be concerned,” said George.

Editor’s Note (August 21): This article has been updated to reflect the number of registered medical cannabis users.

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