Introduction

In Canada, it is estimated that there are between 35,000 and 45,000 young people who are living without a stable or safe residence [1]. In Vancouver, a recent homeless count revealed that there are nearly 700 youth aged 13 to 24 living on the streets of Greater Vancouver [2]. Youth experiencing street entrenchment (i.e., those experiencing homelessness or without stable housing, frequently in the context of other kinds of overlapping exclusion along axes of race, class, sexual orientation and gender identity) are vulnerable to a variety of health and social harms [3], including elevated rates of substance use [4], mental illness [5], blood-borne and sexually transmitted infections [6, 7], poor nutrition [1] and exposure to physical, sexual and emotional violence [1, 8]. Street entrenched youth are also vulnerable to fatal and non-fatal overdose, particularly in the context of the current crisis driven by the proliferation of illicitly-manufactured fentanyl, related analogues and fentanyl-adulterated stimulants [9]. In the province of British Columbia, illicit drug overdose deaths among young people between the ages of 10 and 18 increased from 3 deaths in 2014 to 18 in 2018, while overdose deaths among young people aged 19 to 29 increased from 83 to 300 across the same time period [10]. The provincial government declared overdose deaths a public health emergency in April 2016 [11].

Amid intersecting crises of homelessness and climbing overdose rates, Vancouver continues to be recognized as an international leader in the rapid implementation of numerous interventions to reduce drug-related harms. In the downtown core, services such as needle distribution programs, supervised injection facilities and overdose prevention sites, the widespread distribution of take-home naloxone kits and the availability of opioid agonist therapies (OAT; e.g., methadone, buprenorphine/naloxone) have been paramount in reducing drug-related harms [5, 12, 13]. Across Greater Vancouver, various public health stakeholders are currently expanding efforts to create a comprehensive substance use care system for vulnerable adolescents and young adults that spans acute and community healthcare settings, including clinics, hospitals, and residential detox, treatment and recovery settings. For example, the local health authority has recently rolled out a new Youth Intensive Case Management Team staffed by nurse practitioners and other healthcare professionals, which provides mental health and substance use care to youth across in- and out-patient community healthcare settings (e.g., drop-in centers, residential treatment centers) [14].

And yet, in this setting service providers continue to struggle to connect young people, and particularly youth experiencing street entrenchment, to care. A largely quantitative body of research from settings across North America has highlighted various barriers to accessing care among vulnerable youth, including long wait times, age restrictions, a lack of trained providers and access to pharmacotherapies, and experiences of discrimination on the basis of gender, race and sexuality [15–19]. For young people experiencing street entrenchment, barriers to services are often compounded for those experiencing the concurrent disorders of substance use and mental health issues [20], and residential instability and mobility across institutional (e.g., government care homes, correctional facilities) and non-institutional (e.g., ‘flop houses’) settings over time [21, 22]. Moreover, among vulnerable youth, negative experiences with various forms of institutionalization and care stretching back to their childhoods can lead them to the conclusion that reducing or eliminating drug use are things best accomplished independently, without professional help [23].

Previous work by our team in Greater Vancouver has demonstrated that one of the emic strategies street entrenched young people may employ to independently mediate their drug use is the use of one substance to transition away from another. For example, many youth in our setting begin using crystal methamphetamine (meth) in order to reduce or eliminate what they view as increasingly problematic crack cocaine and opioid use [23]. Preliminary work by our team similarly demonstrates that young people may use cannabis to reduce the harms caused by other forms of substance use [24] and in order to transition away from more harmful forms of substance use (e.g., injection drug use; see Boyd et al. [25]).

In Canada, cannabis is one of the most widely used substances, particularly among young people. Health Canada reports that cannabis use among youth ages 16 to 25 is over two times greater than among adults [26], and UNICEF reports that Canadian youth have some of the highest rates of cannabis use in the world [27]. Although previous research has documented the role cannabis can play in harm reduction, substance use and mental health treatment and pain management, this research has predominantly been quantitative and focused on adult drug-using populations [28–33]. Less research has examined qualitatively the therapeutic uses of cannabis among youth, particularly youth experiencing street entrenchment (see Bottorff et al. [34] for an exception). Research by Jenkins and colleagues [35, 36] underscores the need to consider these kinds of social spatial contexts in order to understand how and why young people use cannabis, and tailor the design and delivery of substance use and harm reduction interventions to meet the needs of specific youth populations. A more nuanced understanding of cannabis use among youth in the context of street entrenchment is particularly important given the markedly widespread use of cannabis use among this population. Although the non-medical use of cannabis by people older than age 18 has been legal and regulated in our study setting since October 2018, cannabis has long been highly accessible and relatively affordable among local youth due to thriving street-based drug scenes and illicit retail storefronts and other outlets that pre-date the regulatory changes [37]. Studies from British Columbia and Vancouver have estimated the prevalence of cannabis use among street-involved youth to be as high as 98% [38, 39], while nearly 20% of youth in this setting report having sold cannabis within the past six months [40]. We undertook the present study in order to examine how young people understood, experienced and engaged with cannabis in the context of drug scene entrenchment and drug use trajectories that included the use of other substances such as alcohol, fentanyl, heroin and meth. Such research is of particular importance in a setting where public health crises of homelessness and an ongoing overdose epidemic have the potential to significantly shape youth’s perceptions and practices surrounding cannabis, as well as the way that stakeholders respond to them.

Methods

Seventy-eight semi-structured, in-depth qualitative interviews were conducted from March 2017 to August 2019 with 56 young people between the ages of 16 and 26 (31 youth completed one or more follow up interviews). Youth were recruited from the At-Risk Youth Study (ARYS), a prospective cohort of over 1,000 street entrenched young people who use drugs that has been described in detail elsewhere [41]. We also conducted 13 interviews with 12 youth-focused care providers (one provider completed a follow up interview), including six family physicians, one nurse practitioner, one nurse, two drug and alcohol counselors, and two social workers. Service providers were recruited by the last author (DF), drawing on her ongoing relationships with those working in the field of youth substance use treatment and care.

Interviews were undertaken by a medical anthropologist (DF) and a research coordinator (MT) trained in qualitative interviewing and facilitated with semi-structured interview guides. Interviews with youth were designed to elicit broad discussions of their substance use and care trajectories, including experiences with and perspectives on cannabis use. For interviews with providers, we sought to elicit their experiences with and perspectives on the rapidly transforming substance use care landscape in Vancouver. While we did not explicitly raise cannabis use among street entrenched youth during these provider interviews, this emerged as an important theme in several conversations. All study participants provided their written informed consent, and youth participants were compensated with a $30 honorarium for their time. We received ethical approval from the University of British Columbia/Providence Health Care Behavioral Research Ethics Board to recruit and interview young people 14 years of age and older as emancipated minors, and therefore no parental or guardian consent was required for any of our youth participants.

Interview findings and emerging analyses for this study were triangulated by drawing on the findings of a larger program of anthropological research conducted by the senior author since early 2008 with street entrenched youth and their providers in Greater Vancouver. This research program has included a focus on tracing young people’s substance use and care trajectories across time and place, and hundreds of hours of fieldwork in the settings of youth’s everyday lives, including the places where they sleep, eat, socialize, work, and access services and systems.

As is common in qualitative and anthropological approaches, data collection and analyses occurred concurrently as the study progressed. Interviews were transcribed verbatim, anonymized, and checked for accuracy. ATLAS.TI software was used to code and manage the data. An initial codebook was generated by DF that captured broad emergent themes and analytic categories (e.g. “experiences with cannabis”). Subsequent fieldwork and in-depth interviews were used by the study team to refine the codebook through the addition of new codes (e.g., “cannabis as harm reduction”). Over the study period, evolving interpretations of the data were discussed with young people in the field by DF, and more formally during subsequent in-depth interviews conducted by DF and MT. In addition, the research team discussed the content of interviews and fieldnotes throughout the data collection and analysis processes. Two Youth Peer Research Associates (BH and SN) assisted with member checking emerging findings and final analyses. We use narrative excerpts from specific interviews and fieldwork encounters to highlight themes we identified across interview accounts and fieldnotes. All names appearing below are pseudonyms.

Results

Youth interview participants included 30 young men, 21 young women, and five non-binary individuals (gender was self-identified by youth). The median age of youth participants was 21. Thirty-one participants self-identified as White, eight self-identified as Indigenous, two self-identified as African Canadian, one self-identified as Middle Eastern, one self-identified as Asian, 11 self-identified as being of mixed ethnicity, and two did not want to identify their race or ethnicity. Consistent with quantitative research from our setting [39], the vast majority of youth study participants engaged in daily, intensive cannabis use at the same time as they cycled on and off other substances perceived to be more harmful (primarily alcohol, opioids and meth). All of the young people who participated in this study had tried cannabis at least once. Interestingly, in the context of substance use trajectories that included “harder” drugs such as fentanyl, heroin and meth, as well as binge alcohol use, many young people did not view cannabis use as a form of substance use per se. For example, during periods of time when they were smoking cannabis or consuming edible cannabis products exclusively (i.e., not engaging in any other forms of substance use), many referred to themselves as “clean off drugs,” “sober” or “drug free.”

Discussion

While some young people in our setting identified negative effects of regular cannabis use, our findings also underscore the therapeutic value of cannabis among many youth in the context of street entrenchment and substance use trajectories that include the intensive use of alcohol, opioids and meth. Despite reasonable access to health and substance use services in a setting like downtown Vancouver, many vulnerable youth instead elect to use cannabis to mediate substance use and mental and physical health issues, as well as to ameliorate some of the harms of, or even transition out of, periods of street-based homelessness. A number of participants explicitly framed cannabis as an effective form of mental health and substance use treatment. Participants used cannabis to reduce or achieve abstinence from what they perceived as more dangerous forms of substance use, and to transition away from harmful routes of administration such as injection drug use. They also used cannabis to transition away from psychopharmaceuticals and medication-assisted substance use treatment (e.g., OAT) that were generally viewed as less effective and “healthy” in the long term. This is consistent with other work by our team [42] which has demonstrated the undesirability of long-term OAT among a large number of street entrenched young people in our setting.

Our findings are consistent with previous studies focused on adult populations which demonstrate that cannabis use can reduce the frequency of prescription [31, 43] and illicit [30] opioid use among people who inject drugs, and can be used to transition away from alcohol, tobacco, crack cocaine, and various other licit and illicit forms of substance use among both street entrenched and non-street entrenched individuals [28, 32, 44]. Motivations for using cannabis as a substitute for other substances have included the limited side effects of regular cannabis use, a lack of painful withdrawal symptoms, and its efficacy in managing nausea, seizures, sleep disorders, depression, anxiety and ADHD [45–47]. Further supporting the value of cannabis as a form of substitution therapy is a 2016 US study, which reported that the use of prescription drugs for which cannabis could act as an alternative (e.g., painkillers) fell significantly in states following the implementation of medical cannabis laws [48].

Our findings also shed additional light on a recent quantitative study by Reddon and colleagues, which found a negative association between frequent cannabis use and initiating injection drug use among street entrenched young people in Vancouver [49]. Taken together, these findings challenge some of the assumptions built into the “gateway drug hypothesis,” particularly as these assumptions apply to vulnerable youth populations whose substance use trajectories include “harder” drugs such as fentanyl, heroin and meth, as well as binge alcohol use. The gateway drug hypothesis posits that the early use of cannabis, tobacco and/or alcohol directly increases an individual’s risk of progressing to more serious forms of substance use in adulthood [50]. Critiques of this hypothesis have emphasized the importance of genetic, psychosocial and environmental factors over the causal effects of a “gateway” substance in shaping harmful drug use trajectories [51–53]. While our findings do not speak to the chronological progression of young people’s substance use trajectories (e.g., from initiating cannabis use to experimenting with “harder” substances such as opioids and meth), they do demonstrate what could be referred to as a “reverse gateway effect” among some street entrenched young people, whereby cannabis use was associated with the intermittent reduction, elimination or prevention of more harmful forms of drug use such as meth and opioid use. This finding is particularly significant in the context of the current overdose crisis, which has claimed the lives of more than 1000 young people in the province of British Columbia since 2016 [10]. Further research is needed to understand how the use of cannabis among youth experiencing street entrenchment might be protective in our and other similar settings in the context of the current crisis. At minimum, we must acknowledge cannabis use as an emic harm reduction and treatment strategy that is commonly employed among some highly vulnerable youth to facilitate periods of transition away from what are perceived as more dangerous forms and modes of drug use, resulting in significant–albeit usually intermittent–reductions in risk and harm from both an emic and public health perspective [36, 54].

The use of cannabis as a form of intermittent harm reduction and treatment among many of our participants may reflect ongoing barriers to professional care among street entrenched young people in our setting. Previous research, including our own, has highlighted the numerous challenges vulnerable youth face when attempting to access substance use care, including the reluctance of many providers to provide OAT to youth [55], the physical location of services in heavy drug using (“triggering”) neighbourhoods [56], the undesirable expectations of particular programs [24], and a longstanding sense of distrust in “the system” [23]. As our previous research [23] as well as that of others [34] has shown, these barriers lead many young people to the conclusion that addressing substance use-related harms, as well as ongoing mental and physical health issues, is something that is best accomplished independently. Research approaches that bring together qualitative methods and implementation science are urgently needed to better adapt and design substance use and mental health services that are accessible, acceptable, appropriate and effective for young people experiencing street entrenchment in our and other similar settings [57]. Interventions must be contextually relevant and responsive to the perspectives and lived experiences of street entrenched youth [35], and work to address the marginalization and exclusion that many of them have experienced across their lives and rebuild their trust in “the system.” Service design and provider education and training must incorporate consideration of the current evidence regarding both the potential risks and benefits of cannabis use among this population, including the role that cannabis can play in intermittently or more permanently reducing or eliminating more harmful forms of substance use and mediating mental and physical health issues.

The youth who participated in this study cycled in and out of forms of substance use (e.g., daily injection meth and opioid use) that generally pose more immediate risks than daily, intensive cannabis use. However, some of our youth participants did emphasize the negative effects of intensive cannabis use. More research is needed to develop a clear picture of both the positive and negative effects of cannabis use among this population. Conducting research on cannabis, particularly with respect to its therapeutic possibilities among youth, is challenging for a variety of reasons [36, 58]. Consequently, the current evidence around the therapeutic value of cannabis is partial and mixed, particularly as it pertains to mental health issues. For example, while relief from anxiety and depressive symptoms are among the most widely reported reasons for therapeutic cannabis use [59], quantitative studies have shown dose-, frequency- and duration-dependent increases in rates of depression and anxiety among individuals who use cannabis, particularly if initiated at a young age [60–62]. Ongoing research has also identified an association between cannabis use and structural and functional brain alterations, particularly among adolescents [63, 64]. The risk of schizophrenia has been associated with chronic cannabis use during adolescence [65]; however, this association might be at least partially explained by a predisposition to cannabis use among individuals with genetic susceptibility to schizophrenia [66, 67]. The most frequently noted adverse effects of cannabis–that is, transient impairments in cognitive and psychomotor function [68, 69]–have been shown to desist during periods of abstinence from cannabis [70]. In sum, while various negative associations have been observed in previous research, we continue to have a poor understanding of what drives these associations and their clinical significance. Moreover, while intensive daily cannabis use during adolescence and young adulthood might indeed cause adverse health effects, these harms must be weighed against the harms associated with the intensive use of substances such as alcohol, meth, heroin and fentanyl–particularly in the context of the current overdose crisis.

In conclusion, our findings highlight the potential benefits and harms of cannabis use among young people in the context of street entrenchment and substance use trajectories that include the intensive use of alcohol, opioids and meth. While a small number of youth spoke to the potential dangers of cannabis use, the majority emphasized cannabis as a tool that allowed them to transition away from what they viewed as more problematic forms of drug use for periods of time, and to relieve longstanding physical and mental health issues. Particularly in the context of the recent legalization of non-medical cannabis use in Canada and amid ongoing overdose and housing crises, it is imperative that future policy and programming interventions and provider education and training be responsive to the ways in which youth in our setting are actively using cannabis to navigate their everyday lives and healthcare needs.

Acknowledgments

We wish to thank the study participants for their contribution to the research, as well as current and past researchers and staff.