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Benefits and risks of cannabinoids

BMJ 2023; 382 doi: (Published 18 September 2023) Cite this as: BMJ 2023;382:p2113

Linked Research

Balancing risks and benefits of cannabis use: an umbrella review of meta-analyses

  1. Tom P Freeman, reader1,
  2. Wayne Hall, emeritus professor2
  1. 1Addiction and Mental Health Group, Department of Psychology, University of Bath, Bath, UK
  2. 2National Centre for Youth Substance Use Research, University of Queensland, St Lucia, QLD, Australia
  1. Correspondence to: T P Freeman t.p.freeman{at}

Strong evidence of both benefits and harms for a range of medical indications

Cannabis is used by an estimated 219 million adults globally (4.3% of the population) with a particularly high prevalence in North America (17.4% of the population).1 The 1961 UN Single Convention on Narcotic Drugs included cannabis with opioids and cocaine as a controlled substance whose use was prohibited, but policies have changed considerably in recent decades. Medical use of cannabis is now permitted in large parts of North and South America, Europe, and Oceania; although, patient access varies considerably across jurisdictions. The use of cannabis for non-medical purposes is also now permitted in Canada, 22 US states, and Uruguay, and several other countries are considering allowing adult use in some form (eg, Germany, Luxembourg, Malta, the Netherlands, and Switzerland). In this rapidly changing policy climate, high quality evidence on benefits and risks are needed to inform policy and clinical practice.

In a linked article,2 Solmi and colleagues (doi:10.1136/bmj-2022-072348) report an umbrella review of the benefits and risks of cannabis. A key strength of their review is the …

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