Routes of administration for cannabis use – basic prevalence and related health outcomes: A scoping review and synthesis Cayley Russell a , Sergio Rueda a,b,c , Robin Room d,e , Mark Tyndall f,g , Benedikt Fischer a,b,c,h,i ,j , * a Institute for Mental Health Policy Research, Centre for Addiction and Mental Health (CAMH), 33 Russell St., Toronto, ON, M5S 1S2, Canada b Department of Psychiatry, University of Toronto, 250 College St., Toronto, ON, M5S 1A8, Canada c Institute of Medical Science (IMS), University of Toronto, 1 King’s College Circle, Toronto, ON, M5S 1A8, Canada d Centre for Alcohol Policy Research, La Trobe University, 215 Franklin St., Melbourne, VIC, 3000, Australia e Centre for Social Research on Alcohol and Drugs, Stockholm University, SE-106 91 Stockholm, Sweden f B.C. Centre for Disease Control (BCCDC), 655 W 12th Ave, Vancouver, BC, V5Z 4R4,Canada g School of Population and Public Health, University of British Columbia, 2206 E Mall, Vancouver, BC V6T 1Z9, Canada h Centre for Criminology & Sociolegal Studies, University of Toronto,14 Queen’s Park Crescent, Toronto, ON, M5S 3K9, Canada i Centre for Applied Research in Mental Health and Addiction (CARMHA), Simon Fraser University, 515 W. Hastings Street, Vancouver, BC, V6 B 5K3, Canada j Department of Psychiatry, Federal University of Sao Paulo (UNIFESP), R. Sena Madureira, 1500, Vila Clementino, São Paulo, SP, 04021-001, Brazil A R T I C L E I N F O Article history: Received 17 March 2017 Received in revised form 31 October 2017 Accepted 2 November 2017 Available online xxx Keywords: Cannabis Legalization Health Policy Routes of administration Use methods A B S T R A C T Background: Cannabis use is common, and associated with adverse health outcomes. ‘Routes of administration’ (ROAs) for cannabis use have increasingly diversified, in part influenced by developments towards legalization. This paper sought to review data on prevalence and health outcomes associated with different ROAs. Methods: This scoping review followed a structured approach. Electronic searches for English-language peer-reviewed publications were conducted in primary databases (i.e., MEDLINE, EMBASE, PsycINFO, Google Scholar) based on pertinent keywords. Studies were included if they contained information on prevalence and/or health outcomes related to cannabis use ROAs. Relevant data were screened, extracted and narratively summarized under distinct ROA categories. Results: Overall, there is a paucity of rigorous and high-quality data on health outcomes from cannabis ROAs, especially in direct and quantifiable comparison. Most data exist on smoking combusted cannabis, which is associated with various adverse respiratory system outcomes (e.g., bronchitis, lung function). Vaporizing natural cannabis and ingesting edibles appear to reduce respiratory system problems, but may come with other risks (e.g., delayed impairment, use ‘normalization’). Vaporizing cannabis concentrates can result in distinct acute risks (e.g., excessive impairment, injuries). Other ROAs are uncommon and under-researched. Conclusions: ROAs appear to distinctly influence health outcomes from cannabis use, yet systematic data for comparative assessments are largely lacking; these evidence gaps require filling. Especially in emerging legalization regimes, ROAs should be subject to evidence-based regulation towards improved public health outcomes. Concretely, vaporizers and edibles may offer potential for reduced health risks, especially concerning respiratory problems. Adequate cannabis product regulation (e.g., purity, labeling, THC-restrictions) is required to complement ROA-based effects. © 2017 Elsevier B.V. All rights reserved. 1 Introduction Cannabis is the most commonly used psychoactive drug globally. Current use rates in the general population typically range from 2–5% in different global regions, yet are highest (10– 13%) in North America; use is generally concentrated among adolescents and young adults (Azofeifa et al., 2016; Health Canada, 2014; United Nations Office on Drugs & Crime (UNODC), * Corresponding author at: Institute for Mental Health Policy Research; Centre for Addiction and Mental Health (CAMH), 33 Russell St., Toronto, Ontario, M5S 2S1, Canada. E-mail address: benedikt.fischer@utoronto.ca (B. Fischer). https://doi.org/10.1016/j.drugpo.2017.11.008 0955-3959/© 2017 Elsevier B.V. All rights reserved. International Journal of Drug Policy 52 (2018) 87–96 Contents lists available at ScienceDirect International Journal of Drug Policy journal homepage: www.elsevier.com/locate/drugpo