The Lower-Risk Cannabis Use Guidelines (LRCUG): A ready-made targeted prevention tool for cannabis in New Zealand.

Cannabis use is common, especially among young people, and associated with risks for select acute and chronic adverse health and social outcomes. New Zealand features overall high cannabis use levels, yet may soon follow other jurisdictions and implement legalization of non-medical cannabis use and supply towards public health objectives. While existing cannabis-oriented interventions mainly focus on primary prevention and treatment (e.g., for dependence), key harms from use are crucially influenced by risk factors that can be modified by the user. On this basis, and similar to other health behavior-oriented interventions, 'Lower-Risk Cannabis Use Guidelines' (LRCUG), consisting of 10 recommendation clusters for lower-risk use, were systematically developed in Canada as an evidence-based, targeted prevention tool towards reducing adverse outcomes among cannabis users. We briefly summarize the concept of and experiences with implementation of the LRCUG elsewhere, and describe how their adoption as a population health intervention may serve public health goals of possible cannabis legalization in New Zealand and elsewhere.

Cannabis is the most commonly used illicit drug globally, with some 250 million estimated active (e.g., past year) users [1,2]. Policy approaches for cannabis have been shifting gradually around the world recently. While criminal prohibition has been the main control framework for decades, Canada, Uruguay, and 11 US states have recently legalized non-medical cannabis use and supply, with reference to public health and safety objectives [3,4]. New Zealand, alongside other jurisdictions, is actively considering a similar policy reform towards legalization of non-medical cannabis use and supply that will be decided in a public referendum in late 2020 [3,5]. Public opinion polls suggest an about split for and against a legalization framework as presented in the draft ‘Cannabis Legalization and Control Bill’. This proposal is very similar to Canada’s laws in: legal use age of 20 years; no public use; commercial production and retail of diverse cannabis products; and home-growing of cannabis allowed [6,7].

New Zealand, along with North America and Australia, is part of a group of ‘high-use’ countries in which 8%–15% of the population report cannabis use, the majority of whom have tried cannabis in their teens. While survey evidence is not wholly consistent, cannabis use has increased among young adults in the general population in New Zealand but declined among adolescents [8,9]. Cannabis use remains concentrated among youth/young adults (e.g., ages 15–29 years), with about one in three reporting recent use but its prevalence of is lower than that of alcohol and tobacco.

Cannabis use is associated with increased risk of a range of adverse health and social consequences [[10], [11], [12]]. These include: acute cognitive, psychomotor control and memory impairment (including severe hallucinations or psychotic episodes); moderately increased driving impairment increasing risks of injury/death; cannabis use disorder/dependence (occurring in 10–25% of users); weak to moderate associations with chronic mental health problems, primarily schizophrenia and depression (with probable bi-directional causality); chronic bronchitis or other pulmonary problems (including possibly increased risk for lung cancer) among those who smoke cannabis (and especially with tobacco co-use); select adverse reproductive/maternal health outcomes (e.g. lower birthweight for newborns) among women using cannabis during pregnancy; and possibly cardio-vascular problems among users of high-potency cannabinoid products. With notable exceptions (e.g., cannabis-impaired driving fatalities), there are few, if any directly attributable (e.g., acute overdose) deaths from cannabis [13]. The lion’s share of the cannabis-related burden of disease is attributable to cannabis-related impairment, and consequential injuries or deaths, and cannabis use disorder (CUD). The cannabis-related disease burden is substantially lower than that for alcohol, tobacco or psychostimulants [[14], [15], [16]].

The main adverse social consequences of cannabis use can include compromised educational attainment, and adverse consequences of arrests and convictions e.g. restrictions on travel and professional disadvantage [[17], [18], [19], [20]]. Arrests commonly involve young and socio-economically marginalized males as a result of selective enforcement practices with related social injustices. Among youth and young adults, adverse health and social outcomes primarily occur among sub-groups of vulnerable users characterized by select, shared risks characteristics [10,21,22]. This fact has major implications for the foci of targeted prevention of cannabis-related harms from a public health point of view, namely the need to give priority to protecting young people from the adverse effects of their youthful cannabis use on their life chances and courses [23].

Among its essential prospective benefits, cannabis legalization allows authorities to regulate cannabis products, distribution and use. It furthermore makes it easier to directly facilitate interventions aimed at users, and specifically to systematically provide risk reduction advise (‘targeted prevention’) to users [20]. Targeted or secondary prevention measures to reduce risky or harmful cannabis use have traditionally been limited, and general prevention efforts have mostly focused on reducing availability and advising against cannabis use [[24], [25], [26], [27]]. This, in part, because risk reduction advice has been seen as implicitly ‘endorsing’ cannabis use as an illegal activity. Recent reviews suggest some evidence for a limited impact of individual targeted risk-reduction interventions, for example, in the form of ‘brief interventions’, for cannabis use [[28], [29], [30]].

A tailor-made population-level targeted prevention tool for cannabis use, the ‘Lower-Risk Cannabis Use Guidelines (LRCUG)’, was developed, originally in 2011 and updated in 2017, in anticipation of cannabis legalization in 2018 in Canada [31,32]. The LRCUG embody health-focused education and ‘behavioral choice’ models that focus on risk factors for adverse harm outcomes from cannabis use, identified by reviews of relevant scientific evidence, that users can modify if they wish to reduce risk of harm with ongoing use. The LRCUG comprise a total of 10 recommendation clusters advising users on how to reduce cannabis use-related risks developed from the consensus of an international group of addiction and health scientists [see Textbox below for the LRCUG’s original recommendations, reproduced with permission]. Important for general uptake and dissemination, the LRCUG have been endorsed by ten leading Canadian organizations [e.g., the Canadian Medical Association [CMA], the Canadian Public Health Association [CPHA], the Canadian Society of Addiction Medicine [CSAM], among others) with health, substance use and addiction focus or mandate. They were also included in education and prevention strategies devised by different levels of governments as part of the implementation of cannabis legalization in Canada. To practically facilitate wide dissemination and uptake, a suite of customized ‘knowledge translation’ products was developed (e.g., infographics, pamphlets, posters, cards, and webinars) for different target audiences and distributed jointly with key stakeholders [33]. The LRCUG, or similar frameworks, have been adapted for use in Latin America and other jurisdictions.

Alt-text: Box 1

Based on the proposed parameters of possible legalization policy in New Zealand, and available assessments of the impact of legalization on cannabis use and harm outcomes to date in other jurisdictions, it is possible that some of these harm indicators, at least in the short-term, may increase [4,34]. Given this, the LRCUG provide a ready-made, evidence-informed population health tool with the potential to reduce the risks of adverse effects among the sizeable population of cannabis users in New Zealand. Moreover, the New Zealand government’s draft legalization bill stipulates mandatory ‘harm minimization messaging’ to be provided to users at cannabis retail interfaces, for which the LRCUG provide a ready and fitting foundation or template [6]. While the scientific evidence informing the LRCUG is evolving and will require future updating, the LRCUG’s concept and approach resemble other, established health behavior guidelines, for example targeting nutritional, cardio-vascular, sexual health promotion or related risk reduction, and – the closely topic-related – low-risk drinking guidelines in place in many English-speaking and other countries [[35], [36], [37], [38]]. Initial assessments suggest that the awareness of, and compliance with the LRCUG’s recommendations among cannabis users in Canada is reasonably good, but with room for improvement [39,40]. Further evaluations are required.

Because patterns and cultures of cannabis use (e.g., in modes of use and types of products used) are rather similar in New Zealand and North America, the LRCUG offer a readily available, credible and tested population health tool for reducing cannabis use related risks and the related public health burden in New Zealand [[41], [42], [43]]. This is, generally, the case and pertinent irrespective of whether legalization will eventually be implemented or not. We urge relevant decision-makers and respectively mandated organizations (e.g., government and health authorities, professional associations) to consider, adopting and effectively disseminating the LRCUG in the interest of advancing and improving cannabis use-related public health in New Zealand.

Beyond the specific scenario of New Zealand, the LRCUG may serve as a valuable intervention concept or tool in at least two ways – especially in jurisdictions that are considering moving away from strict prohibition towards more health-oriented cannabis policy approaches. The LRCUG respond to the concrete need and create awareness for targeted prevention among both health policy-makers and the sizable populations of (especially young) people who make the choice for cannabis use, and may concretely contribute to reduce the public health burden from cannabis through ‘lower-risk’ cannabis use. Depending on context, the LRCUG’s recommendations may need to be adapted to local norms and cultures related to cannabis use. Overall, the LRCUG offer a useful element towards ‘normalizing’ policy and intervention approaches for cannabis towards public health similar to those in place for other everyday activities (e.g., driving, nutrition, alcohol use) that come with risks for health that are intended to be minimized.

Competing interests/funding declarations

Dr. Fischer acknowledges support from the Hugh Green Foundation Chair in Addiction Research, Faculty of Medical & Health Sciences, University of Auckland; he furthermore reports grants and contract funding on cannabis-related topics from public only (e.g., public funding, government) agencies. Dr. Farrell directs the National Drug & Alcohol Research Centre, funded by the Australian Federal Government Department of Health, and has received unrestricted research funding from Indivior, Sequeris and Mundipharma and the Therapeutic Goods Authority in Australia to assess the effectiveness of medicinal cannabinoids and to develop clinical guidance. Dr. Newcombe has received grant funding from the New Zealand Health Promotion Agency, a public agency partially funded by the levy on alcohol produced or sold in New Zealand. Other authors report no related competing interests.