Intended for healthcare professionals


Strengthening the evidence for medicinal cannabis and cannabinoids

BMJ 2019; 367 doi: (Published 21 October 2019) Cite this as: BMJ 2019;367:l5871
  1. Tom P Freeman, senior lecturer1,
  2. Celia Morgan, professor of psychopharmacology2,
  3. Chandni Hindocha, research fellow3
  1. 1Addiction and Mental Health Group (AIM), Department of Psychology, University of Bath, Bath, UK
  2. 2Psychopharmacology and Addiction Lab, Department of Psychology, University of Exeter, UK
  3. 3Clinical Psychopharmacology Unit, Research Department of Clinical, Educational, and Health Psychology, University College London, UK
  1. Correspondence to: T P Freeman t.p.freeman{at}

Alternative trial designs and patient registries can rapidly generate robust data on efficacy and safety

Draft recommendations by the National Institute for Health and Care Excellence (NICE) did not recommend prescription of unlicensed cannabis based products to patients on the NHS.1 The potential benefits for people with chronic pain were considered too small relative to costs, and the quality of evidence was rated too low to recommend use in children with severe treatment resistant epilepsy.1 At present, the only way to get cannabis products for medicinal use in the UK is through prescriptions issued by private clinics2 (which are prohibitively expensive) or the illicit market (which carries risk of prosecution as well as unknown product content, quality, and safety). Given the vocal requests for access to these products from patients and their carers,3 stronger evidence is urgently needed so that these products can be made available in situations where they are known to be effective and safe.

Cannabis based medicines vary in their content of Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD), which have contrasting mechanisms of action, efficacy, and …

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