HEALTH EFFECTS OF CANNABIS
© Her Majesty the Queen in Right of Canada, as represented by the Minister of Health, 2017
Cat.: H129-73/2017E (Print)
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H129-73/2017E-PDF | ISBN: 978-0-660-08291-2 (Print)
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978-0-660-08290-5 (PDF) | Pub.: 170012
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There is also the serious risk of:
f interacting with criminals or criminal organizations
f criminal charge and prosecution
Mental health effects
In some people, cannabis use increases the risk of developing
mental illnesses like psychosis or schizophrenia, especially
in those who:
f start using cannabis at a young age
f use cannabis frequently (daily or almost every day)
f have a personal or family history of psychosis
and/or schizophrenia
Frequent cannabis use has also been associated with
an increased risk of:
f suicide
f depression
f anxiety disorders
Health effects on youth
Cannabis use that begins early in adolescence, that is
frequent and that continues over time has been associated
with increased risk of harms. Some of those harms may
not befully reversible.
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Adolescence is a critical time for brain development,
as research shows the brain is not fully developed until
around age 25.
Youth are especially vulnerable to the effects of cannabis
on brain development and function. This is because THC
in cannabis affects the same biological system in the
brain that directs brain development.
It is important for parents, teachers, coaches and other
trusted adults to be ready to talk with youth about drugs.
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Volkow et al. (2016) Effects of cannabis use on human behavior,
including cognition, motivation and psychosis: a review. JAMA Psychiatry
73(3): 292–7. www.ncbi.nlm.nih.gov/pubmed/26842658
Health effects on pregnancy
and children
Just like with tobacco, a pregnant woman or new mother’s
use of cannabis can affect her fetus or newborn child
which can lead to health problems.
The toxins in cannabis are carried through the mother’s
blood to her fetus during pregnancy and in the breast milk
following birth.
Heavy cannabis use during pregnancy can lead to lower
birth weight of the baby. It has also been associated
with longer-term developmental effects in children
and adolescents, such as:
f decreases in:
f memory function
f the ability to pay attention
f reasoning and problem-solving skills
f hyperactive behaviour
f increased risk for future substance use
Addiction
Contrary to popular belief, people can become addicted to
cannabis. Individuals who use cannabis can develop a cannabis
use disorder, which at its extreme can result in addiction.
Continued, frequent and heavy cannabis use can cause
physical dependency and addiction.
Research has shown that THC in cannabis causes an increase
in levels of dopamine, the pleasure chemical, in the brain.
This motivates people to keep using it.
Addiction can develop at any age but youth are especially
vulnerable
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as their brains are still developing.
Some people are also more prone to becoming addicted
than others. It’s estimated that 1 in 11 (9%) cannabis users
will develop an addiction
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to it. This statistic risesto about 1
in 6 (17%) for people who started using cannabis as a teenager.
If a person smokes cannabis daily, therisk of addiction is
25% to 50%.
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Chadwick et al. (2013) Cannabis use during adolescent development:
susceptibility to psychiatric illness. Frontiers in Psychiatry. 4: 129.
www.ncbi.nlm.nih.gov/pubmed/24133461
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Volkow et al. (2014) Adverse health effects of marijuana use.
New England Journal of Medicine 370(23): 2219–27.
www.ncbi.nlm.nih.gov/pubmed/24897085