What would change if we legalised cannabis? – Expert Q&A

A promised referendum on recreational cannabis next year has raised questions on what a legal, regulated cannabis market might look like.

The proposed regulated market would include:

  • A minimum age of 20 to use and purchase recreational cannabis
  • Regulations and commercial supply controls
  • Limited home-growing options
  • A public education programme.

Experts say these potential law changes will impact the wider drugs market and may have flow-on impacts on the supply of synthetic drugs, which are believed to have been responsible for the deaths of about 65 people.

The SMC asked experts to discuss how potential legislative changes might change the drugs market and impact everyday Kiwis. 

Dr Marta Rychert
Dr Geoff Noller
Associate Professor Joe Boden
Professor Michelle Glass


Dr Marta Rychert, Research Officer, Shore & Whāriki Research Centre, College of Health, Massey University, comments:

What impact do you expect legalisation and commercialisation will have on the cannabis market?

“In an ideal world, we’d expect that legalisation would encourage the transition of users from the illegal black market to legal cannabis products and contribute to a gradual reduction in the size of the black market. But the actual experience is much more complex.

“Early evidence from Colorado – one of the first jurisdictions to legalise recreational cannabis, shows black market activity is likely to persist, at least in the early stages of legalisation. And this is despite the fact that prices are competitive with the black market: the average retail price of cannabis per gram has declined by 48% since the opening of legal retail outlets in 2014.

“A legal, regulated cannabis market can offer a number of advantages over the black market, including quality, consistency and safety of products. The impact of legalisation on the black market will depend on how well these aspects are controlled and how well they respond to cannabis user expectations.

“Legalisation will create a new legal sector. The size of a new legal market for cannabis will be largely dependent on the regulatory regime that is adopted. Evidence from alcohol suggests the bigger and more commercial the market, the more harms we are likely to see.

“Given the relative novelty of commercial cannabis regimes in the US, the evidence on the impacts of cannabis legalisation on levels of use is limited. For example, one study found an increase in adolescent use in Washington but no change in Colorado after legalisation. Longer term insights can be gleaned from studies on implementation of medicinal cannabis markets in the US. They found no impact on youth use but higher rates of use, daily or near daily use, and incidence of cannabis dependence in adults. These findings suggest that legalisation, particularly via a commercial model, should include the possibility of increasing adult cannabis use and related health costs.”

What are the alternatives to the commercial market model and what do you suggest is the best approach? 

“Cannabis social clubs are small co-ops where users can register and grow their cannabis for a small fee. This approach is in operation in Spain, Belgium and Uruguay. Uruguay is an interesting case study because cannabis can be accessed there via three ways. Consumers can choose to legally join a cannabis social club, grow their own cannabis at home or buy it from licensed pharmacies. I think New Zealand could learn from this approach. It is also worthwhile looking at our own models developed for other commodities. For example, in a number of New Zealand communities, alcohol is sold via so-called licensing trusts – these are community enterprises where profits from alcohol sale are redistributed back to local community, e.g. cultural, health and sports activities. A similar approach could be developed for cannabis.”

What impact do you expect legalisation and commercialisation will have on the wider market for recreational drugs?

“Legalisation may have some impact on other drug markets in New Zealand. For example, we recently found that illegal drug users think it is now easier to get methamphetamine than cannabis. Anecdotal reports also suggest people are offered methamphetamine by their dealers due to cannabis shortages in parts of the country. If cannabis is legalised, some of these users will exit the black market altogether, potentially reducing the customers base. It is still uncertain how illegal drug dealers will respond to legalisation though.

“On the other hand, some suggest that legalisation of cannabis may encourage use of other drugs. However, it remains debatable to what extent new legal cannabis users would seek other drugs on the illegal drug markets.”

How do you think the potential law changes will affect incarceration rates?

“Over 2000 people are convicted of cannabis use or possession annually, but according to statistics from 2016/17 cannabis possession was the only offence in just 400 cases, and only three of these resulted in imprisonment.

“This would suggest that incarceration rates will not change dramatically (as there is not much incarceration due to cannabis use and possession offences alone anyway) but the length of incarceration and life impacts from conviction will be reduced. This is significant, as a cannabis conviction can have life-long implications for employment, travel opportunities and living arrangements, and these disproportionately affect Māori (with 42% of people imprisoned for cannabis offences being Māori).”

How does the social cost and social harm of cannabis compare with the social harm and social cost of synthetic drugs?

“There are no economic analyses comparing social harm of cannabis and synthetic drugs in New Zealand context. While ‘cannabis’ is one drug, the term ‘synthetic drugs’ cover hundreds of different compounds – they have very different harm profiles on individual levels.

“In the popular media context the term ‘synthetic drugs’ refer to the most harmful substances. Indeed, some 65 deaths have been linked with the use of synthetic drugs in the last two years and this number is unprecedented for New Zealand. Lost productivity at work, school problems, drug driving and addiction are among other harms associated with synthetic drugs.

“Cannabis, on the other hand, is often portrayed as harm-free, but this is not the case. For example, studies estimate that 1 in 5 people who have used cannabis in their lifetime met criteria for cannabis use disorder. Among other problems are impaired driving, or lower educational achievement among those who start use early in life. In summary, harms from cannabis and synthetic drugs are different – both qualitatively and quantitatively.”

What about the people who have concerns about drug driving – will these changes make a difference and how do we safeguard drivers?

“Cannabis intoxication affects driving abilities – it has been estimated to increase crash risk approximately two times. Drug driving is a challenging policy issue and many countries that have legalised cannabis implemented policies to ensure safety on roads. These include tests of behavioural impairment, saliva and blood testing. Unlike alcohol, cannabis impairment is much harder to detect by standardised methods. For example, THC (the main psychoactive ingredient in cannabis) can be detected in blood at very low concentrations long after any cannabis-related driving impairment has disappeared, particularly for frequent cannabis users. It seems that some combination of behavioural impairment and laboratory testing can be a feasible way forward to detect cannabis-impaired drivers.

“In New Zealand, 1 in 3 past-year users of cannabis report driving while under the influence of cannabis. Just like with alcohol, a strong education campaign and enforcement is needed.”

Do you think these potential changes will steer people away from synthetics? What else should be done?

“Historically, synthetic drugs were first developed to circumvent prohibitive drug laws and they were marketed as alternatives to ‘traditional illegal drugs’, including cannabis. Given this background, we could expect that cannabis legalisation will reduce demand for these synthetic alternatives. Indeed, there is some evidence that countries with more liberal cannabis policies do not experience the synthetic drug crisis that we have witnessed in New Zealand.

“On the other hand, it is important to keep in mind that synthetic drugs are often used by vulnerable and marginalised populations including homeless who may not have opportunity to participate in the new legal cannabis market. Like with any drug problem, wrap-around services will be critical for populations experiencing systemic problems. As problems with synthetic drugs is a developing issue, a comprehensive early warning system that is able to detect new threats in a timely fashion is also critical.”

No conflict of interest.

Associate Professor Joe Boden, Department of Psychological Medicine, University of Otago, Christchurch, comments:

What does the research consensus say about the links between cannabis and violence?

“There is very little credible evidence for a link between cannabis and violence. Observed associations generally arise because of the drug use patterns of individuals with conduct disorder, who were already generally violent prior to ever using cannabis.”

What impact do you expect legalisation and commercialisation will have on the cannabis market?

“It depends on what form of legalisation and commercialisation we have. If it is tightly regulated, we are more likely to reduce cannabis-related harm, and are unlikely to increase rates of use. A loosely-regulated system (like we have for alcohol) is likely to increase cannabis-related harm and rates of use. The Cabinet paper released in May suggests it will be a tightly-regulated system.”

What impact do you expect legalisation and commercialisation will have on the wider market for recreational drugs?

“There is good evidence from overseas for substitution, in which legal cannabis replaces the use of other drugs (the evidence is best for opioids). Therefore, I would expect rates of use of other drugs to go down.”

What about the people who have concerns about drug driving – will these changes make a difference and how do we safeguard drivers?

“If rates of use increase, rates of drug driving will also increase. The Police will need to be provided the resources and training for better detection and interdiction of drug intoxicated drivers.”

Do you think these potential changes will steer people away from synthetics? 

“If cannabis is legalised for recreational use, synthetics (particularly synthetic cannabis) will likely disappear from the market.”

No conflict of interest.

Dr Geoff Noller, PhD, Department of General Practice and Rural Health, Dunedin School of Medicine, University of Otago, comments:

What impact do you expect legalisation and commercialisation will have on the cannabis market? 

“This is a complicated question, in part because at the time of answering it, we don’t know what precise form any reform of current legislation will take. Having said this, the Government has given us some idea of which way they’re intending move should New Zealanders vote in favour of reforming our cannabis laws in 2020; for example, they’ve indicated what will likely be part of a potential new regime.

“But even this relatively ‘buttoned down’ approach will potentially have significant effects on the ‘market’. Obviously the illicit or black market for cannabis will be affected significantly, with a potential array of options for people to purchase and even grow their own cannabis. It remains to be seen what the commercial aspect of any new cannabis regime might look like because it’s unlikely the model ultimately proposed by the government will be anything like the strongly commercial market that is emerging in the US. It is likely, however, that options for different forms of cannabis products will increase, with edibles and products available for vaping probably appearing, possibly along with numerous other products. In short, the market will become more nuanced and diversified. For this reason, the potential options for the cannabis market won’t be limited just to consumers, but also will provide opportunities for business ranging from production to manufacturing, marketing and distribution, not only of cannabis products but also equipment, including vapes.

“It’s very probable also that there will be an array of options for people with an interest in medicinal cannabis products, i.e. not just businesses but also patients. This is in part because the current legislation resulting from the amendment to the Misuse of Drugs Act for medicinal cannabis is very limited and will not meet the needs of what is possibly a large population of patients who derive benefits from the use of cannabis for therapeutic purposes. Therefore, unless it is revised, it’s probable that those wanting to use cannabis therapeutically will access what they need via the commercial non-medical market.”

What impact do you expect legalisation and commercialisation will have on the wider market for recreational drugs? 

“It’s hard to say how any reforms will impact on the market for other drugs as probably the majority of New Zealanders currently using illicit drugs will continue to do so in the same fashion as the availability of these will not necessarily change due to cannabis law reform, with the possible exception of synthetics. There will, however, likely be an increase in cannabis use, as a small proportion of New Zealanders have previously reported being dissuaded from using cannabis due to it being illegal.

“There could, however, also be a shift away from illicit drugs that people have replaced their previous cannabis use with, due to workplace drug testing, back towards cannabis. Therefore the consumption of drugs like methamphetamine and synthetics might reduce, as might alcohol.”

How do you think the potential law changes will affect incarceration rates? 

“If meaningful reform of the cannabis laws does occur, there will be some reduction in incarceration rates, but these are unlikely to be huge as the numbers of those incarcerated solely for cannabis are not large, with cannabis convictions trending down from a high of over 4000 in 2008 to under 1500 in 2017. In terms of actual imprisonment for cannabis alone, these are relatively few. However, cannabis charges are often factors in other convictions, so there might be a change in some sentencing patterns. Also some sections of New Zealand society (youth, males, and Māori in particular) are represented disproportionately in these statistics and the costs associated with them. And even for small numbers the costs are significant.

“Additionally, other sentences associated with cannabis are also likely to decrease, as the criteria for offences such as personal use and possession of cannabis, use and possession paraphernalia and related offences will have to be revised.”

How does the social cost and social harm of cannabis compare with the social harm and social cost of synthetic drugs? 

“On paper, the social cost and harm of cannabis appears significantly greater than that of synthetics. The Drug Harm Index (DHI, 2016) estimated the total cost of cannabis harm at $1.28 billion dollars, or cost of harm per user at $2100. This compares with a per user harm for synthetics of $2800, but due to the lesser number of synthetics users the overall cost of the latter is much less, despite the fact that synthetics are likely to have been responsible for at least 65 deaths since 2017. Cannabis by contrast cannot cause fatal overdose, though of course deaths may occur as a result of accidents due to impairment from cannabis.

“The DHI also notes specific harms from cannabis that would be reduced if reform occurred, e.g. its estimated $306 million in enforcement costs would clearly reduce, as a significant number of offences involving cannabis relate to minor offences involving personal use and possession which, though not necessarily resulting in incarceration, do accumulate “enforcement” costs (police hours, courts, etc., i.e. it is estimated that a day in court costs around $12,000). Many of these costs would therefore be reduced.

“However, the DHI report is a problematic analysis of drug harms. It combines cannabis with synthetic cannabis in a single harm category, and does not offset in its calculation of harm for the benefits of drug use (including cannabis, e.g. a preference to use cannabis over more dangerous drugs like alcohol and methamphetamine).

“Again, however, if reform did occur, it would be likely that some increase in use would occur, with potential flow-on results such as impact on driving, as well as accidental ‘poisonings’ resulting in hospital admissions. The latter is slightly problematic though as often people concerned about accidental consumption of cannabis, particularly involving young children, fail to appreciate that while the event might be distressing, it will not cause severe harm (cannabis cannot cause fatalities through ingestion alone).”

What about the people who have concerns about drug driving – will these changes make a difference and how do we safeguard drivers?

“This is a complicated question, with interpretations of data often ‘muddied’ by unclear data or analyses that conflate historic use of cannabis with actual impairment. Having noted this, a recent detailed US analysis by the US National Highway Traffic Safety Association (NHTSA), following the legalisation of cannabis in a number of US states suggests that when data are correctly analysed, there appears to be either no elevated crash risk associated with cannabis only, or even a reduced risk of crashes. They note the following:

 “While a number of previous studies have shown some increased risk associated with marijuana use by drivers, many studies have not found increased risk. As was noted previously, studies that measure the presence of THC in the drivers’ blood or oral fluid, rather than relying on self-report tend to have much lower (or no elevated) crash risk estimates. Likewise, better controlled studies have found lower (or no) elevated crash risk esti- mates. Thus, the results of this study are consistent with the previous well controlled studies. Compton, R. P., & Berning, A. (2015). Drug and alcohol crash risk. Journal of Drug Addiction, Education, and Eradication, 11(1), 29.”

Do you think these potential changes will steer people away from synthetics? What else should be done?

“When legal synthetic cannabis products were available – prior to their banning in 2014 with the Psychoactive Active Substances Amendment Act 2014, at least 95% of those using these products were previously cannabis users. The principal reasons for those people shifting to the use of legal synthetic products appeared to be price, consistency of product/effect and legality. It is likely, therefore, that if herbal cannabis and derived products were to become available, most people would prefer these.

“Probably a major factor will be price – if legal cannabis remains more expensive than synthetic cannabis (really we should not even call the latter ‘cannabis’, just ‘synthetics’), then there will remain a market for synthetics. The other determining factor is potency, with synthetics being very potent and short-acting. For this reason, if legislation prohibits the availability of higher potency cannabis, the problem of synthetics will remain to some extent.”

Conflict of interest statement: Along with part time employment at the University of Otago, Dr Noller manages an independent research consultancy. He is currently engaged in a contracted research project involving an online survey of the behaviour of medicinal cannabis patients, with medicinal cannabis patient advocacy organisation, Medicinal Cannabis Awareness New Zealand (MCANZ).

Professor Michelle Glass, Head of the Department of Pharmacology and Toxicology, University of Otago, comments:

How does the social cost and social harm of cannabis compare with the social harm and social cost of synthetic drugs?

“I don’t think we have enough evidence yet on social cost and social harm of synthetic cannabinoids. We don’t even have good data in New Zealand on use of them right now. The long-term impact of chronic and heavy cannabis use is significant, it is likely the long term impact of synthetic cannabinoid use will be profound, but it’s too soon to say.”

Do you think these potential changes will steer people away from synthetics? 

“In the international market this hasn’t been the case – people are continuing to use synthetics despite the clear evidence of harm from them. There seem to be two main reasons for this – one, they aren’t detected in most work place drug testing; and two, they are generally cheaper than cannabis.”

No conflict of interest declared.