Cannabis is the most commonly used illicit drug globally, with more than 200 million current users (estimated for 2010).1 In the Americas, cannabis use rates and associated burden of disease (i.e., dependence) are highest in the North America region, where, in 2010, there were an estimated 32 million users (or 11% of the adult population), including < 2 million users (or 0.6% of the population) with dependence, translating into 276,000 disability adjusted life years (DALYs), mostly in the age group 15-29 years.2,3 These indicators are lower overall in Latin America (7-8 million users, or 3% of the adult population), with the highest continental levels in the Southern Cone region (e.g., Argentina, Chile, Uruguay), with 169,000 individuals with dependence (0.28% of the population) and 26,000 related DALYs.2,3 For Brazil, recent epidemiological data are limited, yet indicate that 2-3% of the general adult population and approximately 5-14% of secondary and post-secondary students engage in current cannabis use.4-6 Survey data suggest that about one in three current cannabis users in Brazil qualify for dependence.7

While for decades, cannabis control has been predominantly prohibition-based in countries across the Americas, there has been a gradual but persistent shift in an increasing number of jurisdictions towards liberalization and a more public health-oriented policy approach in recent years.8-11 Canada, the majority of the United States, Argentina, Chile, and Colombia are but a few jurisdictions which have implemented law-based medical cannabis use and access programs, as far back as almost 20 years ago.12-14 In Argentina, Mexico, and Jamaica, personal (non-medical) cannabis use is decriminalized; some jurisdictions, such as Jamaica, even permit limited personal growth. Finally, several U.S. states (various years since 2012), Uruguay (2013), and Canada (2018) have formally moved toward legalization of non-medical cannabis use and supply policy frameworks, within which recreational cannabis use and distribution is legally regulated.

Cannabis is a psychoactive compound with a well-documented variety of associated acute and chronic health risks (for a series of seminal reviews, see e.g.15-18). While the overall cannabis-attributable disease burden is lower than that of licit drugs like alcohol or tobacco, also because instances of direct cannabis-related mortality are rare, morbidity outcome risks exist in different domains.2,19 For example, cannabis use acutely impairs cognition, memory, and psychomotor control, and can lead to hallucinations or psychotic symptoms.15,20 Acute cannabis impairment is associated with an about twofold increase in risk of fatal or nonfatal motor-vehicle accident involvement, a risk further amplified when alcohol is involved.21,22

There are associations with adverse mental health outcomes, including (approximately twofold) risks with schizophrenia and depression; however, the directional and causal nature of these is complex.15,23,24 Cannabis (marijuana) smoking is associated with pulmonary-bronchial problems, and may contribute to lung cancer.25 Cannabis use can result in use disorder (e.g., dependence); while older epidemiological data estimated that less than one in ten cannabis users will develop dependence, more recent population-level data have found rates as high as 25-30%.26,27 Furthermore, cannabis use may negatively impact reproductive outcomes (e.g., newborn health) and cardiovascular health, as well as reduce social and educational attainment or performance among young people.28-30 The latter risks have been linked to possible adverse effects of intensive cannabis use on brain structure and functioning, though concrete evidence is limited or mixed.31,32

While the above cannabis policy changes remain controversial, they indicate and are embedded within a liberalizing trend footed on overall increasingly public health-oriented thinking in psychoactive substance control options and strategies.33-35 Liberalization in itself, however, does little to help or improve public health outcomes, and the impacts of legalization policies on public health remain uncertain and will not be known definitively for some time.11,36,37 However, liberalization creates policy environments that provide the opportunity to implement measures and approaches to prevent or reduce adverse consequences associated with substance use that would otherwise be impossible in contexts of illegality. One such primary element or tool are regulations – for example, focusing on drug product quality or strength, access and availability, or pricing and taxing, all of which are standards established in alcohol and tobacco control and provided for legal cannabis use and distribution schemes.38-40

A population health approach to cannabis control and interventions moves away from a binary approach defined by “abstinence/good vs. use/bad” to a more refined approach in which general prevention has its place, yet where equal emphasis is put on reducing risks and harms among users along a continuum of interventions, targeted prevention, and treatment.41-43 Next to system-level regulation, however, evidence consistently shows that individual substance use behaviors, and corresponding choice-making by users, substantially influence related health – and, on the population level, public health – outcomes. Hence, informing and influencing individual users to make choices to lower substance use-related health risks, based on scientific evidence, constitutes an integral component for a public health approach.44 Similar behavioral choice tools or approaches have been established in other areas of health, for example, through evidence-based guidelines for nutritional, occupational, cardiovascular, or sexual health.45-48 In the psychoactive substance use field, the prime example of such evidence-based tools are Low-Risk-Drinking Guidelines, which have been implemented – mainly in North America – as a population health tool towards reducing risky alcohol use and related harms.49,50

Such targeted prevention is categorically easier, but also necessary to achieve public health goals, when the activity in question – here, specifically cannabis use – is legal rather than illegal.51 The overall prevalence of cannabis use (up to 25-40% of individuals aged 15-25 years52,53), combined with its impending (and now current) legality in Canada, provided the primary impetus to develop an evidence-based, targeted health-risk reduction tool for those making the choice to use cannabis. This initiative was concretely boosted by initial evidence indicating various predictors of cannabis-related health harms as “modifiable” through user behavior or choices. On this basis, a multi-national team of preeminent addiction and health science experts conducted systematic data reviews (2016-2017) on cannabis use and health, focusing on user-modifiable factors for reduced adverse health outcomes. The resulting evidence was reviewed and quality-graded, and a set of 10 recommendations on how cannabis users may most effectively reduce the risks for associated health harms was developed by expert group consensus. The resulting Lower-Risk Cannabis Use Guidelines (LRCUG54; see the Recommendations in English and Portuguese in Box 1) were initially published and launched in June 2017. Since then, the LRCUG have been formally endorsed by nationally leading addictions and health agencies in Canada, including the Canadian Centre on Substance Use and Addiction, the Canadian Council of Chief Medical Officers of Health, the Canadian Medical Association, the Canadian Mental Health Association, the Canadian Pharmacists Association, the Canadian Public Health Association, the Canadian Society of Addiction Medicine, the Centre for Addiction and Mental Health, and the Mental Health Commission of Canada. Furthermore, various practical “knowledge translation” products – for example, graphic-design posters for public display, brochures for users (including young people) and an evidence summary for health professionals – have since been developed, electronically and in hard copy, and distributed widely.55,56 In parallel, efforts towards international versions of the LRCUG have been developed. For example, an adapted and official version of the LRCUG for Uruguay – where non-medical cannabis use and supply are legal and regulated57 – has been formally launched by the national drug control and cannabis regulation agencies.

While non-medical cannabis use is currently not legally permitted in Brazil58 – and we do not seek to take explicit positions here on specific policy reform options for consideration – it nevertheless is a common activity, particularly among young adults. Different evidence-based options along the continuum of interventions are required to most effectively reduce the burden of cannabis-related health harms in the Brazilian population. Given these circumstances, it is appropriate and useful to present and make available the LRCUG to the context of health-oriented interventions and policy development for cannabis use in Brazil. While further culture- and setting-specific adaptation may be beneficial, the LRCUG (as is the case in other jurisdictions) may serve as a science-based information and discussion tool regarding health risks associated with cannabis use as well as a concrete, evidence-based targeted prevention tool to reduce risks for acute and chronic adverse health outcomes among cannabis users.

Prevention and other types of interventions for substance use typically require adaptation for the specific contexts for which they are intended; such adaptation has to strike a sensible balance between consideration of subjective sociocultural realities and fidelity to the intervention’s original spirit and content.56,57 For adaptive consideration of the LRCUG for Brazil, it first needs to be restated that – unlike in countries such as Canada or Uruguay – cannabis use remains illegal in Brazil; hence, behaviors and issues addressed in the LRCUG, while with the intention of protecting individual and public health, may involve matters of illegality, which naturally renders direct implementation and utilization challenging. Furthermore, there are distinct features of cannabis-related behaviors relevant for adaptive consideration. For example, most cannabis use in Brazil occurs through smoking of combusted cannabis products, most of which involves products of unknown or low quality.58,59 “Safer” alternatives for use methods considered by the LRCUG, like non-smoked products, are typically not available, and vaporizers or e-cigarette devices themselves are even illegal in Brazil, and therefore face additional barriers for utilization in practice.60,61 Moreover, the distinct practice of (smoked) use of cocaine-based products combined with cannabis is common among some Brazilian sub-populations, especially marginalized and impoverished individuals.62-64 While this typically occurs for “harm-reducing” effects (e.g., to mitigate acute withdrawal or mental health problems), distinct associated risks will require special consideration. Similarly, alcohol use and its consequential harms are prevalent among the Brazilian general population,65,66 and the distinct risks and harms from combined use of alcohol with cannabis may also warrant specific consideration towards the objectives of lower health risks. Finally, illegal drugs are associated with an extensively high toll of violence (including homicides) in Brazil; although this predominantly relates to producers and traffickers, including organized crime, and mostly involves psychostimulants,67-70 the prevention of violence-related harms for cannabis users (e.g., in the context of exposure to illegal markets) may need to form an explicit consideration in adaptation of the LRCUG for the particular sociocultural contexts of Brazil.