What do we know about cannabis legalisation?

Cannabis has been made legal in many parts of the world, including Canada, Uruguay, and over 20 US states.¹

But not everyone agrees with legalisation. Some see it as progress, while others are concerned about the risks.²

And some agree with legalising cannabis but differ on the preferred approach to regulating the way it is accessed, used and sold.

Here, we unpack the different approaches to cannabis legalisation and regulation, and the impacts so far.

What is legalisation?

Legalisation is when a drug is legal to access, use or sell and is regulated by the government.

In Australia this includes alcohol and cigarettes, and prescribed medications such as oxycodone or benzodiazepines.

And, some drugs that were previously illegal can now be prescribed by doctors for certain illnesses, such as medical cannabis, MDMA and psilocybin (magic mushrooms).

How is legalisation different to decriminalisation?

Decriminalisation involves the removal of a criminal penalty for using or possessing small amounts of illegal drugs, but buying and selling remains illegal.³

Some Australian states already have decriminalisation policies in place for cannabis.

But in countries where cannabis is legalised without needing a prescription, you can purchase it from retail stores if you’re over a certain age - similar to alcohol.

Why legalise cannabis?

Despite law enforcement efforts, cannabis remains widely available and used.^4,5

And we know that criminalising cannabis use leads to various harms, including criminal justice impacts and higher levels of stigma.^2,6,7

Legalising cannabis can potentially reduce harms by:

• decreasing people’s contact with the criminal justice system
• reducing stigma
• encouraging help-seeking
• improving product safety and standards by regulating supply
• decreasing the power of organised crime networks
• increasing tax revenue to fund cannabis health and treatment services.^5,8

We also know that commercialising cannabis products can increase harms, as private companies prioritise profits over public health.

So, it’s important to consider how different legalisation approaches can limit commercial influence and prevent harms.

How does cannabis legalisation work?

There are different cannabis legalisation approaches or ‘models’.

Many parts of the US and Canada have taken a commercial approach - where cannabis products are sold online or in stores by private businesses.⁹ These models generally have fewer government restrictions on availability, product types, and advertising.⁹

But there are also less commercialised models of legalisation, including:

• Government monopoly: where the government controls all sale, supply and production of cannabis, and private businesses aren’t involved. Quebec has taken this approach to tightly regulate access and use revenue from sales to fund cannabis prevention and treatment services.^9,10
• Not-for-profit: includes availability through cannabis social clubs, where members grow and supply cannabis for personal use, but don’t sell to the public or make any profits.¹¹ It can also be where cannabis is sold at pharmacies and the government controls the price, types of products available and advertising isn’t allowed. In Uruguay, citizens over 18 can buy cannabis in pharmacies, grow it at home or join a cannabis club.¹²

What are the impacts of cannabis legalisation?

In North America, legalisation has generally meant fewer cannabis-related arrests, cheaper products, and more people buying cannabis in legal markets.^2,10,13

Tax revenue has also increased, especially where governments play a bigger role, like in Quebec.¹⁴

But the big question remains; how does legalisation affect public health, including cannabis use and related harms?

Does legalising cannabis lead to more people using cannabis?

Research shows that legalising cannabis generally leads to an increase in use among adults who are allowed to buy it.^15-18

But there’s a worry that underage use of cannabis could also rise.¹⁹

Adolescence is a time of major physical, social and personal development. And teens can be more vulnerable to the effects of regular cannabis use, including the risk of dependence.¹⁹

Research from North America shows mixed results on how legalisation affects teen cannabis use. Some studies show no change, others report increases or decreases.^15-18,20

For instance, one study found more cannabis use among 13–18-year-olds in Washington after legalisation, but not in Colorado.²¹

And in Uruguay, legalisation didn’t lead to an overall rise in recent use or risky use among secondary school  students.¹²

So far, there’s no clear pattern of increased teen use, but more research is needed.

What are the impacts of cannabis legalisation on road safety?

With legal cannabis more accessible, there's concern about an increase in impaired driving and crashes.

Cannabis can slow down reaction time, affect coordination, and impact concentration – making driving unsafe.^22,23

We know cannabis can increase the risk of crashes, but the evidence is less clear about whether legalising cannabis is linked with an increase in traffic accidents.²⁴

Some studies have found legalisation is associated with more traffic accidents.

For example, Ontario saw a rise in emergency room visits for cannabis-related traffic injuries after an increase in cannabis retail stores.^25,26

But overall, the evidence is mixed and often limited by poor data and study quality.^2,17,25

What are the impacts of legalisation on cannabis dependence?

As adult cannabis use rises, there’s concern that legalisation could lead to more people experiencing dependence, or cannabis use disorder (CUD).

Some US studies have found an increase, while others haven’t.²⁷

For example, after legalisation in several US states CUD rates went up among adults over 26 and teens aged 12–17, but not for 18–25-year-olds.²⁸

And a recent study of US adults aged 18–64 found no link between legalisation and changes in CUD diagnoses.¹

What are the other health impacts or risks?

In parts of Canada, more people have gone to emergency departments (ED) for cannabis-related issues since cannabis products became more available.

In Ontario, ED visits rose by 22% after restrictions on commercial retail sales were relaxed. The increase was most significant among younger people aged 15-24.²⁹

And when cannabis edibles - like chocolates and lollies - became legal in some provinces, paediatric hospitalisations for cannabis poisoning jumped - 7.5 times higher than before legalisation in Alberta, British Columbia, and Ontario.³⁰

But Quebec, which banned youth-friendly edibles, didn’t see the same rise.³¹

In fact, past-year cannabis and edible use among 12–17-year-olds declined in Quebec but increased elsewhere.³²

Hospitalisation rates also doubled in provinces that allowed edibles, but stayed stable in Quebec.³³

Where to from here?

We still need more research to fully understand how legalisation affects public health and safety.

So far, heavily commercialised models appear to cause more harm.

Going forward, it’s important to explore whether stricter rules on products, availability, and advertising can help reduce those harms.

What do Australians think about legalising cannabis?

The latest National Drug Strategy Household Survey (NDSHS) found support for legalising cannabis in Australia is at an all-time high.⁴

In 2022–23, 45% of people backed legalisation for personal use - up from 41% in 2019 - and more supported it than opposed it (33%).⁴

For the first time, more people favoured legalisation than harsher penalties for selling or supplying cannabis.⁴

Approval of regular use has also grown, rising from 6.6% in 2007 to 23% in 2022–23.4

More information

To find out more about the Alcohol and Drug Foundation’ s position on cannabis regulation, or related topics visit:

• ADF’s position on cannabis regulation
• Cannabis drug fact page
• What is medicinal cannabis?
• A health-based approach to alcohol and other drugs
• NDARC webinar: Cannabis use, risks and potential: Evidence on a moving target