The government must ease and encourage medical cannabis research

It’s been over a year since the rules were changed to allow clinicians to prescribe cannabis-based medicinal products (CBMPs) but very little has changed.

Despite the countless headlines, powerful campaigns and desperate patients and families, prescribing of CBMPs is rare. For those seeking to access these products, this is a baffling torment.

At the root of this problem is the stark paucity of evidence to support the effectiveness of these products in most cases. We need gold-standard randomised controlled trial data — without these data, clinicians are unable to confidently and safely prescribe.

On 20 November 2019, the Royal College of Psychiatrists published a position statement on cannabis-based medicinal products, which details this lack of evidence. Our report echoes previous work by NHS England, the National Institute for Health and Care Excellence, and a review published by The Lancet Psychiatry which found “insufficient evidence to provide guidance on the use of cannabinoids for treating mental disorders within a regulatory framework”[1],[2],

But if the research doesn’t happen now, when will it? We owe patients properly researched, evidence-based medicines, but the lack of high-quality research is denying them this. We must break down the barriers standing in the way of this research.

Despite changes to its scheduling in November 2018, cannabis remains under Schedule 1, so it cannot be possessed or prescribed by clinicians. And conducting research is difficult — it is permitted only under a Home Office licence that is costly and time-consuming to obtain. The law on cannabis must be relaxed if we are to produce meaningful research on its potential benefits.

Given these barriers, many pharmaceutical companies — despite having the capital needed for trials — are reluctant to invest. The government must apply top-down pressure to encourage pharmaceutical companies to play their part in providing the evidence-base for these products and patient groups must continue to push.

As a starting point, we support NHS England’s recommendation that the National Institute for Health Research should support research into the five priority research areas, including the use of cannabis-derived products in treating fibromyalgia, chronic pain, spasticity, and treatment-resistant epilepsy, and the effects of tetrahydrocannabinol (the psychoactive compound in cannabis) in combination with cannabidiol on the frequency of seizures, brain structure and neurophysiological performance[4]

Without change, we will remain stuck in this impasse in which the potential benefits of cannabis are not fully understood and clinicians lack the evidence base and guidance to prescribe. Let’s fund this research properly and build a rigorous body of evidence. It’s what patients and their families deserve.


Adrian James, registrar, Royal College of Psychiatrists


[1] NHS England. 2019. Available at: (accessed November 2019)

[2] National Institute for Health and Care Excellence. 2019. Available at: (accessed November 2019)

[3] Black N, Stockings E, Campbell G et al. Lancet Psychiatry 2019; In press. doi: 10.1016/S2215-0366(19)30401-8

[4] NHS England & NHS Improvement. 2019. Available at: (accessed November 2019)

Last updated
The Pharmaceutical Journal, The government must ease and encourage medical cannabis research;Online:DOI:10.1211/PJ.2019.20207372

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