Select Committee on Science and Technology Second Report


14 March 2001

By the Select Committee appointed to consider Science and Technology.




1. In this short Inquiry we wanted to follow up issues relating to our earlier Inquiry, Cannabis: The Scientific and Medical Evidence (November 1998).[1] In that Report, we recommended that doctors should be permitted to prescribe an appropriate preparation of cannabis if they saw fit, albeit as an unlicensed medicine and on a named-patient basis. In a departure from the usual convention, the Government rejected this recommendation on the morning the Report was published. The Government's written reply was no more encouraging.[2] In March 1999, therefore, the Committee wrote:

    "we regret that the mind of the Government appears to be closed on this issue, and hope that the results of new research now under way may cause them to revisit our recommendations at an early date."[3]

2. This Inquiry was convened to examine the current state of research into the therapeutic uses of cannabis, the roles of the Home Office and the Medicines Control Agency in the licensing of cannabis-based medicines, and more recent issues relating to the prosecution of therapeutic cannabis users.

3. One hearing was held. We took evidence from: Charles Clarke MP, Minister of State in the Home Office; Dr Brian Davis, from the Medicines Control Agency Licensing Division; and Ms Judy Sanderson from the Health Services Directorate in the Department of Health. The transcript of that session is appended to this Report.

4. In addition to receiving written memoranda by these witnesses, we also solicited written material from the Alliance for Cannabis Therapeutics (ACT); G. W. Pharmaceuticals, a private company engaged in the development of cannabis-based medicines; and the Medical Research Council. These too are appended to this Report. We extend our thanks to those who took the time to contribute evidence to this Inquiry.

5. In 1998, we recommended that cannabis and its derivatives should continue to be controlled drugs. We still hold that view. We consider that any debate on the legalisation of cannabis and cannabis-based medicines should maintain a clear distinction between therapeutic and non-therapeutic use. This report is concerned solely with the therapeutic use of cannabis and cannabis-based medicines.


6. The Medical Research Council (MRC) recently approved awards totalling over £1.5 million involving two new trials:

In addition, the MRC has awarded over £600,000 to fund basic cannabinoid research.[4]

7. Progress on the implementation of these trials, however, has not been rapid. Dr Zajicek's trial has only just started to recruit its projected 600 patients, while the precise operational details of Dr Holdcroft's trial have yet to be finalised.

8. The two MRC-funded trials are "proof of principle" trials, rather than trials of a specific medical preparation. While we welcome good quality research into the therapeutic effects of cannabis, we are concerned that the timescale for developing usable therapeutic preparations from these trials is extremely long.

9. A private company, however, G. W. Pharmaceuticals, has also conducted extensive research into the development of a cannabis-based medicine. From written evidence submitted to us, we are pleased to note that the company is making some progress, both in establishing the efficacy of a cannabis-based medicine in the treatment of patients with multiple sclerosis as well as spinal cord injuries, and in developing suitable medical preparations. It is planning to move to Phase III clinical trials shortly.[5]

10. G. W. Pharmaceuticals has also made progress in improving the mode of delivery of cannabis-based medicines. It has developed a sub-lingual spray which seems to avoid the dangers inherent in smoking herbal cannabis, and the difficulties of controlling the dose during oral administration.[6]


11. We are pleased to note that the Government now display a more encouraging attitude towards the licensing of therapeutic preparations of cannabis than we have previously detected. The Minister was quick to deny suggestions that the Government were hiding behind scientific opinion. Should the quality, safety and efficacy of an appropriate preparation of cannabis be established, we were assured that the Government would reschedule cannabis from Schedule 1 to Schedule 2 of the Misuse of Drugs Regulations 1985.[7] In effect, the Minister assured us that once a safe, effective, cannabis-based medicine had been licensed by the Medicines Control Agency, the Government would actively co-operate in permitting it to be prescribed.

12. The Government's policy has not in fact changed since their response to our Cannabis report in 1998. Up until now we have sensed that the authorities have been dragging their feet, at least partly because they may have feared that permitting therapeutic preparations of cannabis to be prescribed would be interpreted by the public as a move towards allowing recreational use. The Minister told us, however, that:

    "there is now a much sharper awareness of the distinction between medicinal use of cannabis and recreational use of cannabis in the public debate" (Q. 49).

We are pleased, too, that the Minister now shares our view that, were the law relaxed on the therapeutic use of cannabis, the Government's hand in suppressing illegal, recreational use would be strengthened (Q. 51).

13. In our original inquiry we were told that research into cannabis was hampered by the "stigma" attached to cannabis and the burden of obtaining Home Office research licences.[8] Since that Report, the Royal Pharmaceutical Society has produced protocols for the conduct of the two MRC-funded "proof of principle" trials of cannabis. In addition, both Dr Zajicek and G. W. Pharmaceuticals have told us that the Home Office has been helpful to them in planning their trials. While we stand by our original recommendation that cannabis should be rescheduled in order to facilitate research,[9] we are at least encouraged that the Home Office is co-operating well with researchers within the current regulations.


14. There have recently been a number of high-profile cases involving the prosecution of therapeutic users of cannabis: the memorandum by the Alliance for Cannabis Therapeutics (ACT) (p. 26) has highlighted a number of them. The decision to prosecute, taken by the Crown Prosecution Service (CPS), does not seem to be consistent from region to region. Moreover, in some cases, juries have acquitted therapeutic users who do not deny the offence, but plead therapeutic use in mitigation; in other cases, defendants have been found guilty and sentenced.

15. The Minister sought to deny that therapeutic cannabis users were subject to "postcode prosecuting". He stressed that the number of therapeutic users who were prosecuted was extremely small when compared to the total of 89,000 cases involving cannabis in 1998.[10] He also said that the variation in the outcome of cases for therapeutic users was less than for other offences, including the recreational use of cannabis. The number of cases of therapeutic users of cannabis being prosecuted is certainly small. Exact statistics are difficult to obtain, however, as the Home Office does not maintain a record of those prosecuted for cannabis use who claim therapeutic use as a defence.

16. The Minister further said that he had no intention of changing the current position, whereby the decision whether or not to prosecute for cannabis-related offences is made locally by the Police and the CPS. He did, however, emphasise that discretion could be exercised at three levels of the prosecution process: by the Police; by the CPS; and by the Courts. Guidelines issued by the Association of Chief Police Officers (ACPO) on dealing with cannabis offences specifically refer to therapeutic use, and recommend that a caution is usually appropriate; the CPS guidelines require that any prosecution should be in the public interest; and the Court of Appeal issues guidance that the possession of small amounts of cannabis for personal use can often be met by a fine.

17. We accept that recreational users, if arrested, may claim to be therapeutic users. We have no wish to dissuade the Police and the CPS from prosecuting those whom they believe to be making such claims falsely.

18. We recognise that the Government do not consider it appropriate to override the authority of the Police and the CPS. We also understand that the present system allows discretion to be used at many levels. We consider, however, that the acquittal of cannabis users by juries on compassionate grounds brings the law into disrepute. In the absence of a viable alternative medicine, moreover, and though we would not encourage smoking of cannabis,[11] we consider it undesirable to prosecute genuine therapeutic users of cannabis who possess or grow cannabis for their own use. This unsatisfactory situation underlines the need to legalise cannabis preparations for therapeutic use.


19. While we are encouraged at the recent change of attitude shown by the Home Office, we consider that decisions taken by the Medicines Control Agency (MCA) appear to be inconsistent. We did not feel that the MCA adequately answered our questions about the proposed use of cannabidiol in cannabis-based medicines. We were also disappointed that the witness from the MCA seemed unprepared even to consider discussing the basis on which the MCA's decisions were made.

20. Raw cannabis (cannabis sativa) contains more than 60 cannabinoids and more than 400 chemical compounds. The two most abundant cannabinoids, which are currently subject to the most detailed investigation, are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Both these cannabinoids are present in raw cannabis. They are also both present in the cannabis oil capsules ("Cannador") which Dr Zajicek is proposing to use in his CAMS trial,[12] and in the cannabis extracts used by G. W. Pharmaceuticals.

21. THC has long been established in the pharmacopoeia. The MCA are satisfied that there is adequate information on the toxicological profile of THC to justify long-term exposure to THC in the CAMS trial (p. 31). An oral preparation of synthetic THC in sesame oil ("Marinol") can already be prescribed by doctors.[13]

22. By contrast, the MCA are unhappy with the toxicology data on CBD. They said that there is some evidence that CBD inhibits spermatogenesis in animals, and that overall there is a lack of adequate data. The MCA have therefore not permitted Dr Zajicek to proceed with his trial of Cannador (cannabis oil) capsules beyond 15 weeks. Moreover, the MCA's decision to insist on further toxicology data on CBD could delay the production of a cannabis-based medicine by G. W. Pharmaceuticals by as much as 2 to 3 years. Were the MCA not to require further extensive toxicological studies on CBD, G. W. Pharmaceuticals claim that they could have a cannabis-based prescription medicine available for patients in 2003.

23. We note that, according to G. W. Pharmaceuticals, the Canadian regulatory authorities have stated that they do not require additional animal toxicology studies for CBD. We put this to the MCA, who refused to comment (Q. 5); we found this refusal highly unsatisfactory.

24. We consider that the decision of the MCA is flawed for three reasons which are discussed in turn below:

    (a) the MCA persist in treating CBD and cannabis oil as "new medicines",[14] though cannabis oil, which contains both CBD and THC, has a long history of human use and appeared in the British Pharmacopoeia Codex until 1948;[15]

    (b) the studies which the MCA took to indicate an inhibition of spermatogenesis involved doses of CBD at least 100 times higher than the doses contemplated by either Dr Zajicek or G. W. Pharmaceuticals; and

    (c) the potential side-effects of CBD about which the MCA are concerned might be regarded as trivial by those patients, such as those suffering from multiple sclerosis, who stand to benefit from medicines incorporating CBD. These concerns could be dealt with by issuing a warning to physicians who prescribe cannabis-based medicines. The attitude of the MCA in not allowing patients to make their own decisions could be regarded as overprotective.

25. Both the MCA and the Home Office persist in treating cannabis-based medicines as new medicines. Cannabis, however, has a history of medical use in man stretching back hundreds of years. For much of the nineteenth century and the first half of the twentieth century, moreover, it was administered in Britain as a tincture (cannabis oil in alcohol): thus the oral administration of cannabis extracts which contain significant quantities of CBD has a long history of medicinal use. In choosing to ignore the long history of safe therapeutic cannabis use, and in classifying cannabis extract (and CBD) as a "new medicine", the Government and the MCA are treating a long-established herbal extract as if it were just another new synthetic chemical, and are thus not making an informed scientific judgement.

26. Campaigners against cannabis have long argued that it may have adverse effects on human fertility. Despite 30 years of trials, however, this has never been adequately proven. The trial to which the MCA refer in their oral evidence (Q. 2) was based on tests in small numbers of animals, and the results were equivocal, even though the administered doses of CBD were 100-1000 times higher than those proposed for any human medicine. In short, we regard the raising of this unsubstantiated issue as further evidence that the MCA have not adopted a positive approach towards the licensing of a cannabis-based medicine.

27. We are concerned that the MCA's approach to the licensing of cannabis-based medicines, and their insistence on the provision of new toxicological data which could delay the approval of such medicines, place the requirements of safety and the needs of patients in an unacceptable balance. Patients with severe conditions such as multiple sclerosis are being denied the right to make informed choices about their medication. There is always some risk in taking any medication; patients and their doctors should certainly be informed about the toxicological concerns that the MCA have raised, but these concerns should not prevent them from having access to what promises to be the only effective medication available to them.

28. Overall, we consider that the MCA's attitude means that cannabis-based medicines are not being dealt with in the same impartial manner as other medicines.

29. We believe that a thorough and impartial reappraisal of the published scientific literature on the safety of CBD and cannabis extracts should lead the MCA to reconsider their present overly cautious stance. We are at least encouraged that the MCA state that they are conducting a more detailed review of existing literature reports on cannabis and CBD.

1   9th Report Session 1997-98, HL Paper 151. Back

2   Published as Appendix 2 of our 2nd Report Session 1998-99, HL Paper 39. Back

3   2nd Report Session 1998-99, HL Paper 39, p. 5. Back

4   For fuller details of these trials and research projects, see the memorandum by the Medical Research Council (p. 33). Back

5   See the memorandum by G. W. Pharmaceuticals (p. 27) for an explanation of the phases of clinical trials. Back

6   An oral preparation of synthetic delta-9-tetrahydrocannabinol in sesame oil is already available as "Marinol". However, the absorption into the blood stream via oral administration tends to be variable, such that patients either underdose themselves and do not obtain benefit from the drug, or risk unwelcome euphoria. Back

7   See Recommendation 8.6, paras 7.6-7.8, and Box 3 (p. 19) of our earlier Report, Cannabis: the Scientific and Medical Evidence. Back

8   See paras 7.18-7.26. Back

9   See our earlier Report, Cannabis, Recommendation 8.6 and Box 8.  Back

10   The most recent year for which figures are available. See Home Office Statistical Bulletin (2000), "Drug Seizure and Offender Statistics, United Kingdom, 1998". Back

11   For reasons explained in our earlier Cannabis report, paras 4.17-4.18, 5.54-5.57, and para. 8.4. Back

12   The primary active ingredients in "Cannador" capsules consist of 70% THC and 30% CBD. Back

13   "Marinol", however, is an unlicensed drug and can only be prescribed on a named-patient basis. It is not generally available and has to be imported from the USA. Back

14   Dr Davis calls them "new products" (Q. 22); the Home Office, in their written memorandum (p. 28), state that before any cannabis-based medicine could be prescribed, it would have to go through the same procedures as "all prospective new medicines". Back

15   See our earlier Report, Cannabis, Chapter 2. Back

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