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Effects of medical and non-medical cannabis use in older adults: protocol for a scoping review
  1. Dianna Wolfe1,
  2. Kimberly Corace1,2,3,4,
  3. Danielle Rice1,5,
  4. Andra Smith6,
  5. Salmaan Kanji1,7,8,
  6. David Conn9,
  7. Melanie Willows3,10,11,
  8. Gary E Garber1,12,13,
  9. John Puxty14,
  10. Esther Moghadam15,
  11. Becky Skidmore1,
  12. Chantelle Garritty1,
  13. Kednapa Thavorn1,13,
  14. David Moher1,13,
  15. Brian Hutton1,13
  1. 1Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
  2. 2Department of Psychiatry, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
  3. 3Institute of Mental Health Research, University of Ottawa, Ottawa, Ontario, Canada
  4. 4The Royal Ottawa Mental Health Centre, Ottawa, Ontario, Canada
  5. 5Department of Psychology, McGill University, Montreal, Quebec, Canada
  6. 6Brain and Mind Research Institute, University of Ottawa, Ottawa, Ontario, Canada
  7. 7Department of Pharmacy, The Ottawa Hospital, Ottawa, Ontario, Canada
  8. 8Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
  9. 9Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
  10. 10Substance Use and Concurrent Disorders Program, The Royal Ottawa Mental Health Centre, Ottawa, Ontario, Canada
  11. 11Department of Family Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
  12. 12Infection Prevention and Control, Public Health Ontario, Toronto, Ontario, Canada
  13. 13School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
  14. 14Faculty of Medicine, Queen's University, Kingston, Ontario, Canada
  15. 15Health Promotion, Ottawa Public Health, Ottawa, Ontario, Canada
  1. Correspondence to Dr Brian Hutton; bhutton{at}


Introduction With its legalisation and regulation in Canada in 2018, the proportion of Canadians reporting cannabis use in 2019 increased substantially over the previous year, with half of new users being aged 45+ years. While use in older adults has been low historically, as those born in the 1950s and 1960s continue to age, this demographic will progressively have more liberal attitudes, prior cannabis exposure and higher use rates. However, older adults experience slower metabolism, increased likelihood of polypharmacy, cognitive decline and chronic physical/mental health problems. There is a need to enhance knowledge of the effects of cannabis use in older adults. The following question will be addressed using a scoping review approach: what evidence exists regarding beneficial and harmful effects of medical and non-medical cannabis use in adults >50 years of age? Given that beneficial and harmful effects of cannabis may be mediated by patient-level (eg, age, sex and race) and cannabis-related factors (eg, natural vs synthetic, consumption method), subgroup effects related to these and additional factors will be explored.

Methods and analysis Methods for scoping reviews outlined by Arksey & O’Malley and the Joanna Briggs Institute will be used. A librarian designed a systematic search of the literature from database inception to June 2019. Using the OVID platform, Ovid MEDLINE will be searched, including Epub Ahead of Print and In-Process and Other Non-Indexed Citations, Embase Classic+Embase, and PsycINFO for reviews, randomised trials, non-randomised trials and observational studies of cannabis use. The Cochrane Library on Wiley will also be searched. Eligibility criteria will be older adult participants, currently using cannabis (medical or non-medical), with studies required to report a cannabis-related health outcome to be eligible. Two reviewers will screen citations and full texts, with support from artificial intelligence. Two reviewers will chart data. Tables/graphics will be used to map evidence and identify evidence gaps.

Ethics and dissemination This research will enhance awareness of existing evidence addressing the health effects of medical and non-medical cannabis use in older adults. Findings will be disseminated through a peer-reviewed publication, conference presentations and a stakeholder meeting.

Trial registration number DOI 10.17605/OSF.IO/5JTAQ.

  • public health
  • epidemiology
  • geriatric medicine

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See:

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  • DW and KC are joint first authors.

  • Twitter @cgarritty, @dmoher

  • DW and KC contributed equally.

  • Contributors BH, KC and DW designed the review. DW prepared the first draft of the manuscript. BS created and tested the search strategies to be used in the bibliographic databases. KC, DR, MW and AS provided clinical expertise, and BH and CG provided review expertise during protocol development. All authors provided input in the planning of the study and also reviewed, provided comment and approved the protocol and manuscript. BH conceived of and is the guarantor of the review.

  • Funding This work was funded as a catalyst grant in 2019 by the Canadian Institutes of Health Research and the Canadian Centre for Substance Use and Addiction.

  • Disclaimer The funders had no role in the development of the protocol.

  • Competing interests BH has previously received honoraria from Cornerstone Research Group for methodological advice related to the conduct of systematic reviews and meta-analysis.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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