Pubdate: Thu, 02 Nov 2017
Source: Winnipeg Free Press (CN MB)
Copyright: 2017 Winnipeg Free Press
Author: Scott McLeod
Page: A7


ANY Canadians can hardly wait for the day recreational use of
marijuana becomes legal. As a medical doctor, I'm far less
enthusiastic. I worry about two things: the experimental nature of
marijuana in medical practice, and the public health consequences of
legalized marijuana.

Before you write me off as overly prudish or an anti-marijuana
conservative, let me say I'm not opposed to legalized marijuana in
principle - I'm just paying attention to the evidence, or rather, the
lack of it. My concern is that as marijuana becomes more easily
available, Canadians may become more inclined to self-medicate with
what's been called a "miracle drug."

Let's look at the research on the medical use of marijuana.

I'm frequently asked about medical marijuana in my pediatric practice
by caring parents who want to help their children with
difficult-to-treat conditions. Over the last few months, parents have
asked me if medical marijuana can be used to treat their child's
attention deficit hyperactivity disorder, autism spectrum disorder or
cerebral palsy, for example.

Parents consider such options because these medical conditions don't
always respond well to traditional prescription drug or therapy
options. Many have heard of "miracle cures" in the media from the use
of medical marijuana.

I wish I could be more positive when they ask. I find the possibility
of a new medicine to benefit conditions that don't respond well to
current medications exciting. Unfortunately, the research isn't there
yet. What do we know so far? Here's the good news. In May of this
year, a double-blind placebo-controlled trial showed that cannabidiol
- - one of the active ingredients within the marijuana plant - reduced
the number of seizures in children with Dravet syndrome, a condition
that results in severe seizures, developmental delays and problems
with movement and balance. The drug may even be approved for use in
difficult-to-treat epilepsy cases by the U.S. Food and Drug
Administration, based on the latest research.

Medical marijuana has also shown a moderate degree of benefit for
patients with neuropathic pain and stiffness, and involuntary muscle
spasms related to multiple sclerosis.

Other uses, such as the treatment of nausea and vomiting following
chemotherapy for those with cancer; assistance with improving weight
gain in HIV patients; improvement in sleep disorders; and the
reduction of the symptoms of Tourette's syndrome all have less
evidence of benefit, but may be promising for some in the future.

But that's where the research ends.

Some of the popularized ways in which medical marijuana is being used,
such as for post-traumatic stress disorder and anxiety, lack long-term
evaluation. While medical marijuana may have short-term benefits,
long-term use may result in increased aggressive behaviours or even
worsening of symptoms.

Today's medical marijuana is also not what it once was. Generally,
we've seen a consistent increase in the THC content of marijuana - the
main psychoactive component - from the 1960s to today. In fact, THC is
being sold by licensed producers at concentrations of greater than

15 per cent in a substantial proportion of available

Why is this a problem? The cannabis used in medical research contains
less than 10 per cent THC. We do know that using cannabis with higher
THC concentrations is associated with an increased risk of psychosis,
but we really don't know much about the medical effects at these
higher concentrations.

While I remain hopeful medical marijuana may bring medical
breakthroughs, more needs to be done to inform the public that its use
remains experimental - and, for the majority of conditions or
ailments, there's minimal to no evidence of benefit, and it may even
be harmful.

Legalization will remove some red tape to allow for more research. But
many patients might opt to self-medicate without ongoing monitoring of
their symptoms or choose to delay seeking help from a medical
professional. These are just some of the public health consequences
that could come from the legalization of something that many see as an
all-purpose medical cure.

It's in everyone's best interests to try to set the record straight.

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Scott McLeod, MD, FRCPC, is a pediatrician practising in Calgary who 
specializes in the diagnosis and treatment of children with 
developmental disabilities, and an expert with
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MAP posted-by: Matt