Feb. 4, 2015 - Among the major health risks linked to cannabis
use, motor vehicle accidents and cannabis use disorders, including
appear to affect the most Canadians. These two factors are the main
contributors to the cannabis-attributable disease burden in Canada,
according to a new study from the Centre for Addiction and Mental Health
cancer and psychosis, two other potential risks often associated with
cannabis, affect fewer Canadians, although frequent cannabis use likely
for a number of lung cancer deaths each year, the researchers suggest.
The study was published online in the Journal
of Public Health.
the first time, we are providing rough estimates quantifying the four
main categories of harms attributable to cannabis use," says lead author
Fischer, senior scientist in CAMH's Social and Epidemiological Research
Department. Cannabis is the most widely used illicit drug in Canada, but
until now, the relative health harms it causes have usually been based
on speculation, he says.
estimate the actual extent of the impact of these four possible risks –
motor vehicle accidents or injuries, cannabis use disorders, lung
cancer and psychosis
– the researchers took data from various sources to estimate the numbers
of Canadians affected, in terms of health problems and death.
Motor vehicle accidents:
The researchers estimated that four to 12 per cent of motor vehicle
deaths or injuries occurred under the influence of cannabis.
Based on motor vehicle accident statistics from 2010, this suggests that
there were 89 to 267 fatalities, and 6,625 to 20,475 injuries in Canada
that year related to cannabis use.
Cannabis use disorders:
Cannabis abuse or dependence was estimated to affect 380,000 Canadians.
This figure is based on a Statistics Canada survey,
showing 1.3 per cent of Canadian adults aged 15 or older could be
considered to be dependent on or to misuse cannabis in 2012. They
estimate that between 76,000 and 95,000 people receive treatment each
year for cannabis-related problems.
Determining the link between cannabis use and lung cancer was
difficult, given the overlap with tobacco smoking, as well as
the amount and frequency of cannabis use and the fact that a diagnosis
usually occurs years after use. However, after considering these factors
in their calculations, the researchers estimated that one to two per
cent of lung cancer deaths could be attributed
to cannabis, corresponding to 130 to 280 deaths a year.
While recent reviews show regular cannabis users have a higher risk of
psychosis, the association between cannabis use and schizophrenia
is driven by a multitude of factors –including genetics – and may also
be bi-directional, the researchers note. However, primarily in relation
to cases where cannabis is used frequently, they estimated 106 to 186
cases of schizophrenia in Canada may be attributed
to cannabis use.
estimates are useful and intended to inform priority setting for public
health interventions," says Dr. Fischer. For instance, the findings
the need to improve ways to detect and deter cannabis-impaired driving,
and expand treatment options for cannabis use disorders, the researchers
Centre for Addiction and Mental Health (CAMH) is Canada's largest
mental health and addiction teaching hospital, and one of the world's
centres in its field. CAMH combines clinical care, research, education,
policy development and health promotion to help transform the lives of
people affected by mental health and addiction issues. CAMH is fully
affiliated with the University of Toronto, and
is a Pan American Health Organization/World Health Organization
Collaborating Centre. For more information, please visit www.camh.ca
For further information:
Kate Richards, Media Relations, Centre for Addiction and Mental Health (CAMH), 416 535 8501 x36015, firstname.lastname@example.org