Some of the most hotly debated aspects of legalized marijuana centre around our youth. How does cannabis use affect adolescent brains? What do parents need to know, given the legal consumption ages established by provincial governments? Experts from UCalgary’s Cumming School of Medicine examine the scientific evidence we have so far on cannabinoids and adolescent brain development, and who might be at most risk. Learn why a public health approach to legalized cannabis is vital, and get practical advice on navigating the new realities of mainstream marijuana. Watch the full webinar recording at: https://go.ucalgary.ca/2018-07-26URCannabisandyouth_LPRegistration.html

1. Cannabis legalization and
youth
Dr. Rebecca Haines-Saah, PhD, Assistant Professor
Dr. Matthew Hill, PhD, Associate Professor
Cumming School of Medicine
July 25, 2018

2. • Associate Professor, Departments of
Psychiatry and Cell Biology and
Anatomy, Cumming School of
Medicine
• Member, Hotchkiss Brain Institute
and Mathison Centre for Mental
Health Research & Education
• Executive Director of the Canadian
Consortium for the Investigation of
Cannabinoids
• Studies neural mechanisms by
which “endocannabinoids”
modulate stress and anxiety
• Twitter @canna_brain
Dr. Matthew Hill, PhD

3. • Assistant Professor, Cumming School
of Medicine, Department of
Community Health Sciences
• Member O’Brien Institute for Public
Health and Mathison Centre for
Mental Health Research &
Education
• Research examines adolescent
mental health and substance abuse
through the lens of a critical health
approach, with a particular focus on
youth cannabis use.
• Twitter @RebeccaSaah
Dr. Rebecca Haines-Saah, PhD

4. Cannabinoids and the
Adolescent Brain

5. • A speaking point that makes its way around the media
is that
“Brain scientists say that cannabis damages the
developing brain”
• But what is the evidence behind this claim
Cannabinoids and the Adolescent Brain

6. Animal Studies
• Some, but not all, animal studies suggest cannabinoid
exposure during adolescence modifies the normative
development of the brain
Cannabinoids and the Adolescent Brain
Rubino et al., 2015

7. But…………
1) Many of these studies use synthetic cannabinoids,
more like Spice, than THC—effects likely not the
same
2) Even for those using THC, we now know THC is not
cannabis and the presence of other molecules, like
CBD, can modify effects of THC
3) Dose and route of administration of THC is not
representative of normative use patterns
Cannabinoids and the Adolescent Brain

8. Human Studies
• Some, but not all, human studies have suggested that
cannabis use during adolescence results in persistent
changes in brain structure and cognitive function/IQ.
Cannabinoids and the Adolescent Brain
Filbey et al., 2014

9. But…………
1) Cannabis users in these studies often represent a
fundamentally different group of people relative to
controls (higher rates of alcohol, nicotine and other
substances, lower SES, education and IQ,
sometimes male:female ratio)
2) Studies are retrospective, not prospective, so
cannot control for baseline differences
3) Most of the studies demonstrating effects of
cannabis do not replicate well.
Cannabinoids and the Adolescent Brain

10. Cannabinoids and the Adolescent Brain
Weiland et al., 2015

11. Cannabinoids and the Adolescent Brain

12. Cannabinoids and the Adolescent Brain
French et al., 2015
• Genetic risk for schizophrenia may render the brain more
vulnerable to negative effects of cannabis – cortical thinning.

13. CONCLUSION
• The current state of evidence does not support the blanket
statement that recreational cannabis use by adolescents causes
irreparable brain damage or persistent impairments in cognitive
function in the average person.
• Variables such as comorbid substance use, life stress or genetics
can amplify the risk of adverse effects, and there may be specific
vulnerable populations who are especially sensitive to negative
effects of cannabis.
• Earlier age of onset, frequency of use and consumption of high
THC concentration cannabis all seem to increase risk that an
adverse effect will occur.
• Follow the Low Risk Cannabis Use Guidelines to minimize risk
Cannabinoids and the Adolescent Brain

14. • Should we be worried….
Cannabinoids and the Adolescent Brain

15. Youth and Public Health Policy

16.  Policies based on prohibition have failed
 Illegal status has not prevented use
 Supply is mostly unregulated
 Criminalization has tangible and lasting harms
 Cannabis-attributable population-level harms are
smaller/lesser
THE CONTEXT FOR POLICY CHANGE IN CANADA:
Youth and Public Health Policy

17. YOUTH & LEGALIZATION: THREE THINGS TO UNPACK
1. Legalization will not protect public health
• Assumes prevalence of use and rates of harms
will increase
2. The legal age of access should be 21-25
• Assumes a higher age will prevent access and
protect youth from using
3. Education should promote abstinence
• Assumes that all use is problematic
Youth and Public Health Policy

18. 28.9
20.6
14.1
4.4
53.7
29.7
20.8
5.6
44.9
9.9
7.2
2.5
0
10
20
30
40
50
60
Ever use Past 12-
month use
Past 30-day
use
Daily use
PercentageofCanadians
15-19
20-24
25+
SOURCES: CTASS: https://www.canada.ca/en/health-canada/services/canadian-tobacco-alcohol-drugs-survey.html
Canadian Cannabis Survey: https://www.canada.ca/en/health-canada/services/publications/drugs-health-products/canadian-cannabis-survey-2017-summary.html
PREVALENCE OF CANNABIS USE: CANADIANS 15+
Canadian Cannabis
Survey 2017:
16-19 years; 41%
20-24 years; 45%
(Statistics Canada)
Youth and Public Health Policy

19. SUBSTANCE ABUSE TRENDS OVER TIME: AB YOUTH
Youth and Public Health Policy
50
47.3
38.9
31.1
37.6 36.4
29.1
17
19.3
21.8
16.5
11.5
4.3 6.2
3.9 3.5
0
10
20
30
40
50
60
2008-2009 2010-2011 2012-2013 2014-2015
Percentageofyouth
Past-Year Substance Use
Alcohol Binge drinking Cannabis Nonmedical use of pharmaceuticals
SOURCES: Dr. Cam Wild. Youth Smoking Surveys 2008-2013; Canadian Student Tobacco, Alcohol, and Drugs Survey 2014-2015; Grades 7-12

20. Police-reported crime for selected offences (Adults, 18+) 2014 2015 2016
2016
rate
% change
2015 -16
% change
2006-16
Drug offences, total 104,518 96,423 95,417 263 -6 -11
Possession – cannabis 57,880 49,577 44,301 122 -12 -10
Possession – cocaine 7,658 7,284 7,056 19 -5 -46
Possession – methamphetamines 4,771 6,130 7,673 21 22 ...
Possession – heroin 1,249 1,602 2,143 6 32 216
Possession – methylenedioxyamphetamine 369 416 255 1 -40 ...
Possession – other drugs 6,668 7,262 7,695 21 7 ...
Trafficking, production or distribution – cannabis 10,700 9,082 10,639 29 -4 -39
Trafficking, production or distribution – cocaine 8,541 7,859 7,161 20 -11 -40
Trafficking, production or distribution – methamphetamines5 1,535 1,849 2,153 6 10 ...
Trafficking, production or distribution – heroin 731 751 912 3 15 126
Trafficking, production or distribution – methylenedioxyamphetamine5 158 153 196 1 -18 ...
Trafficking, production or distribution – other drugs5 4,258 4,458 5,233 14
SOURCE: http://www.statcan.gc.ca/pub/85-002-x/2016001/article/14642/tbl/tbl05-eng.htm (2016) https://www.statcan.gc.ca/daily-quotidien/170724/t001b-
eng.htm (2014-15);
ARRESTS IN CANADA: 2014-2016 (18+)
Youth and Public Health Policy

21. SOURCE: Nutt, D. J., King, L. A., & Phillips, L. D. (2010). Drug harms in the UK: a multicriteria decision analysis. The Lancet, 376(9752), 1558-1565.
COMPARING POPULATION-LEVEL HARMS
Youth and Public Health Policy

22. The prohibition paradox
SOURCE: Canadian Drug Policy Coalition. http://drugpolicy.ca/ https://pbs.twimg.com/media/C8lq0brXYAA028e.jpg
Youth and Public Health Policy
CANADA
COLORADO

23. HARMS TO YOUTH: FREQUENCY AND AGE OF ONSET
 Most people who use cannabis do so
infrequently; and without significant negative
health or social outcomes
 Most use concentrated amongst young people
and youth, and tapers off with age (25+)
 Initiating cannabis use in early adolescence
increases the risk of experiencing cannabis-
related harm, longer cannabis-use trajectories,
earlier transitions to problematic use
SOURCE: National Academies of Medicine (2017); Dr. Elaine Hyshka. Cannabis and Public Health Forum, University of Calgary (2017).
Youth and Public Health Policy

24. Is keeping, or making something illegal the best way
to make it ‘safer’ and to prevent the potential for
health and social harms associated with use by
youth?
SOURCE: Fischer, B., Rehm, J., & Crépault, J. F. (2016). Realistically furthering the goals of public health by cannabis legalization
with strict regulation: Response to Kalant. International Journal of Drug Policy, 34, 11-16.
PUBLIC HEALTH BEYOND PROTECTION
Youth and Public Health Policy

25. SOURCE: https://www.cpha.ca/lower-risk-cannabis-use-guidelines-canada

26. CONCLUSION: DOING CANNABIS EDUCATION AND
PREVENTION IN A NEW CONTEXT
 Talking about drug use does not cause drug use
 LISTEN TO YOUTH experiences and perspectives
 Youth and families need credible tools
 Educate to empower rather than protect
Consider that the best drug prevention might not
even be about drugs at all
Youth and Public Health Policy