The Australian Medical Association (AMA) has expressed its opposition to the Greens’ adult-use bill, claiming it would increase youth cannabis consumption. However, the body’s submission is misleading at best, writes honahlee co-founder Will Rayner.

The AMA’s submission to the Senate inquiry on the Greens’ legalisation bill is a masterclass in how to mislead the public.

Will Rayner

It sets out its case against legalisation strongly from the start, warning against the harms allegedly seen overseas.

It claims that, since legalisation in Canada, cannabis consumption rates in youth have increased, along with increased emergency department presentations and cannabis use disorder diagnoses.

While I (and honahlee) support legalisation, increased youth cannabis consumption is concerning. When we legalise, we’ll need to ensure that area is addressed in detail. 

That said, the AMA’s claims go against what I’ve read about Canada, so I decided to check the citations in its submission.

The first study cited doesn’t measure youth cannabis consumption rates. It’s a survey on the perception held by mental health service providers in Ontario. While opinions are important, they aren’t factual data and shouldn’t be cited that way.

The second source says the opposite of what the AMA claims:

“Since 2019, recent cannabis use in Canada has modestly increased among adults but not among adolescents.”

The AMA cites the author of the second source, Emeritus Professor Wayne Hall, four times in its submission. It seems strange to directly contradict the source you’re trying to rely on.

I reached out to Professor Hall to ask how he felt about his work being used by the AMA to oppose legalisation.

He said: “The AMA has long opposed cannabis legalisation, so it is not surprising that they focus on my work on possible health-related harms of legalisation. If I tried to correct the selective citation of my publications on cannabis I would get nothing else done.”

The Canadian government has already done the research by directly surveying the population. The data collected doesn’t show the increase in consumption the AMA claims exists.

In fact, it shows the opposite – youth consumption is currently lower than pre-legalisation. The data is open to anyone to view via this link.

I reached out to the AMA to clarify exactly what evidence it is relying on to substantiate its  claim.

A representative pointed me to a claim in the mental health provider survey study (Kourgiantakis et al., 2023).

“Since legalisation came into effect, the rates of cannabis use in Canadian youth have increased.” [4,5,6,7,8,9]

This claim appears to be well supported, with references to six additional studies. However, the response I got from the AMA mentioned this increase was also attributed to COVID-19.

It felt strange that a statement implying a causal link between legalisation and increased youth consumption would cite a study looking at the effects of COVID-19 so I decided to take a closer look.

Out of the six citations:

  • Two show a small increase in youth consumption (4,5)
  • Two show a decrease in youth consumption (6,8)
  • One shows a general increase in the US and Canada, but notes the increase is the same regardless of legal status (7)
  • One is an online survey of around 300 people ranging from 18 to 29 years old, who already consume cannabis, six weeks into COVID, asking them to reflect on how their consumption has changed since legalisation (9)
  • None claim that legalisation has affected trends in youth consumption.

I’ve included links and details on each citation at the end of this article.

To sum up, in the AMA’s submission, it has:

  • Contradicted the sources it relied on
  • Ignored the evidence that disproves its claim.

Does this feel like a group that has the best interests of Australian public health in mind? Or are these the actions of a group desperately looking for evidence to confirm what it already believes?

Prohibition will come to an end in Australia, eventually. It probably won’t be because of the Greens’ Legalising Cannabis Bill 2023, but it will happen. 

Australia is late to the party, so we will face incredible policy pressure from the massive international adult-use cannabis corporations. 

If the AMA continues to deny reality then it won’t be taken seriously in any discussion regarding cannabis regulation.

Citations from the AMA submission

4. Trends in youth cannabis use across cannabis legalisation: Data from the COMPASS prospective cohort study

Uses the COMPASS study (16/17 and 17/18 school years) and one after (18/19 school year).

The abstract of the study reads: “Youth cannabis use remains common with ever-use increasing from 30.5% in 2016/17 to 32.4% in 2018/19. In the repeat cross-sectional sample, the odds of ever use in the year following legalisation were 1.05 times those of the preceding year (p=0.0090). In the longitudinal sample, no significant differences in trends of cannabis use over time were found between cohorts for any of the three use frequency metrics. Therefore, it appears that cannabis legalisation has not yet been followed by pronounced changes on youth cannabis use.”

A 1.9% increase over three years. No significant differences in trends.

5. Patterns of cannabis use among Canadian youth over time; examining changes in mode and frequency using latent transition analysis

This study uses the same COMPASS study as above, but only uses data from 2017–2018 and 2018–2019.

It’s primarily concerned with how youth are consuming cannabis. It makes no claim to represent a trend in Canadian youth.

“This study has some limitations to note. First, it used purposive sampling, and as such results are not generalizable to all Canadian youth…”

6. What does adolescent substance use look like during the COVID-19 pandemic? Examining changes in frequency, social contexts, and pandemic-related predictors

A mid-2020 study on the effect of COVID-19. Nothing to do with the effect of legalisation.

The results don’t even show an increase in the number of youth consuming cannabis (it actually went down).

“For most substances, the percentage of users decreased; however, the frequency of both alcohol and cannabis use increased.”

7. Prevalence and modes of cannabis use among youth in Canada, England, and the US, 2017 to 2019

This was an online survey conducted in the US, Canada, and the UK.

When it comes to Canadian legalisation, it comes to a similar conclusion as the initial COMPASS study analysis: “The extent to which the increases observed among youth in Canada are the result of non-medical cannabis legalisation is unclear, given that similar increases were observed in the year prior to legalisation (2017 to 2018), as the year following legalisation (2018 to 2019)…”

It has some very interesting results for the US though: “A supplementary analysis between US states that had and had not legalised recreational cannabis found no differences in 2019 for prevalence of cannabis use in the past 12 months or past 30 days…”

8. Changes in youth cannabis use after an increase in cannabis minimum legal age in Quebec, Canada

Not a study on the effects of legalisation. It actually looks at the effect of increasing the legal age of purchase in Quebec, which happened in January 2020 (well after legalisation).

The results are unsurprising: “In this study, the increase in Quebec’s cannabis MLA from 18 to 21 years was associated with a significantly lower increase in cannabis use among youths aged 18 to 20 years in Quebec than in other provinces.”

I find this fascinating because it works directly against the AMA’s assertion. Legalisation allowed Quebec to set a minimum purchase age.

9. Changes in cannabis consumption among emerging adults in relation to policy and public health developments

A survey of 312 individuals who:

  • Reported smoking and/or vaping cannabis in the last 12 months
  • Were living in Canada
  • Were aged 18 to 29 years old

The survey was conducted in 2020, and asked participants to reflect on their past use before COVID, and before legalisation.

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1 Comment

  1. Well done Will. Some in the medical profession seem inclined to demonise cannabis. There are many pros and cons of legalisation but misrepresenting data in not useful to either position.