Pubdate: Sat, 17 Feb 2018
Source: Vancouver Sun (CN BC)
Copyright: 2018 Postmedia Network Inc.
Author: Douglas Todd
Page: G3


Psychologists point to 'compelling evidence' of cannabis' potential
health impairments

Apart from the #Metoo maelstrom and the housing crises in Toronto and
Vancouver, few things stir up Canadians more than marijuana, which its
promoters claim is the cure for everything from glaucoma to brain disease

Should private outlets sell recreational marijuana? Is it more
enjoyable to smoke or swallow cannabis? Will I get rich on pot stocks?
Is it possible to remove the criminal underground from Canada's $6
billion-a-year cannabis industry?

With the legalization of recreational marijuana, expected in July, in
Canada - which has among the highest usage rates in the world - the
B.C. government this month announced plans to regulate and sell it,
opting for one ounce at a time to those age 19 and above. Informal
polling suggests a slim majority approve.

Meanwhile, the social libertarians argue that virtually any attempt to
restrict cannabis is a victory for nanny-state prudishness. Others act
as if cannabis is like "Soma," the all-healing drug in Aldous Huxley's
Brave New World. Opponents, meanwhile, counter that legalization could
turn cannabis into even more of a scourge, especially for young brains.

The latest group to add their voice to the messy debate over
legalization is Canada's psychologists, the clinician-scientists who
therapeutically face troubled clients, but also research the effects
of drugs, from alcohol to antidepressants, on the human mind, body and

For those who regularly use cannabis, the word is largely discouraging
from Psynopsis, the official magazine of the Canadian Psychological
Association, which represents about 7,000 psychologists.

The entire recent edition of Psynopsis is devoted to cannabis
legalization in Canada, a country in which about one in three young
people are users. Every article in the magazine, but one, errs on the
side of extreme wariness.

The conclusions of the Canadian Psychological Association's task force
on the legalization of cannabis verge on devastating.

The task force says regular cannabis use among teens "is related to
poorer education outcomes, lower incomes, suicidality, greater welfare
dependence and unemployment" and, among the population at large,
increased risk of motor vehicle collisions.

The Canadian Psychological Association's task force also says
"cannabis use can disrupt normal adolescent brain development,"
affecting verbal learning, memory and attention. "Some of these
effects continue even after cannabis use is discontinued."

The task force maintains "cannabis use is linked with an earlier age
of onset for psychosis, and the risk of psychosis onset is greater at
higher levels of cannabis use."

A lead member of the task force, Ontario psychologist David Teplin,
laments how legalizing cannabis has the "potential to further decrease
perceptions of harm," by normalizing usage.

Teplin acknowledged that "the public health burden of cannabis use is
evidently less than that of alcohol, tobacco or other illicit drugs,"
which was his nod to recognizing how beer, wine and spirits have
become integral to European and North American society - for good, and
often in excess, for ill.

However, Teplin's lead article was mostly devoted to reviewing the
"compelling evidence" that cannabis is associated with a wide range of
harms, including cognitive impairments, increased dependence, poorer
pregnancy outcomes and pulmonary problems.

Another Psynopsis article, by psychology professor Andrea Smith of the
University of Ottawa, says marijuana harms young brains while they're
"under construction. =C2=85 Far too many teens that use cannabis regularl
become apathetic and perform poorly."

The University of Montreal's Josiane Bourque, a biomedical scientist,
indirectly suggested in a separate piece that advocates shouldn't mock
earlier claims about "reefer madness," which linked marijuana with
mental illness. "Studies from the last three decades," she said, "have
provided substantial evidence of a two-to three-fold increased risk
of a first episode of psychosis in cannabis users."

As a counterpoint, the official magazine of Canada's psychologists
offers one semi-positive piece about marijuana legalization. It comes
from a University of B.C. team - psychology professor Zach Walsh,
masters' student Michelle Thiessen and PhD student Kim Crosby.

The UBC scholars maintains preliminary research suggests "cannabis may
be effective for reducing problematic use of alcohol and other drugs,"
including prescription medications. The UBC group looks forward to
this summer when "Canadians will have the privilege to decide for
themselves the role that cannabis will play among the range of
approved options for altering mood and cognition."

It is relatively hard to find scientific research that defends
marijuana use. But a North American-wide group led by UBC's Walsh,
which included Thiessen and Crosby, was responsible for one of the
more significant projects to that end. Their reviews of 60 studies
maintains that marijuana "may have the potential" for treatment of
post-traumatic stress disorder, does not appear to lead to abuse of
self or others and might not have long-lasting effects on mental function

As is usual when researchers submit to medical publications, however,
the UBC authors were asked to declare if they had any "conflicts of
interest." Walsh, Thiessen and Crosby acknowledged they receive
funding from Tilray Canada, a B.C.-based medical marijuana producer,
which last month signed a supply agreement with Shoppers Drug Mart.

Another study of marijuana with mixed messages comes from a University
of California psychologist, Nicholas Jackson. He found declining
intelligence scores among teenage marijuana users might be more
attributable to their difficult family situations and general
delinquency. The University of London's Claire Mokrysz and colleagues
also found cigarette smoking was just as responsible as marijuana for
teenagers' poor educational outcomes.

With such scientific results coming in all over the place, it should
be clear that when psychologists say there is an urgent need for more
research into the positive, negative and neutral effects of cannabis,
they're not kidding.

Even if some are eager for grants to further their careers, they're
justified in pointing to the need for more difficult-to-obtain
evidence on cannabis because Canada, like many Western countries, is
heading into uncharted mental-health territory by legalizing pot for
medical and recreational use.

As with most debates, the ideologues in the battle over legalization
run the danger of unnecessarily polarizing us into caricature
cheerleaders or fear mongers. They stifle reasonable discussion.
Canada won't be able to figure out how to move ahead on legalization
without more thorough data.
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MAP posted-by: Matt