Select Committee on Science and Technology Ninth Report

CHAPTER 8 OPINION OF THE COMMITTEE

Medical use of cannabis: recommendations

  8.1     We recognise that, in all the evidence we have received, there is not enough rigorous scientific evidence to prove conclusively that cannabis itself has, or indeed has not, medical value of any kind.

  8.2     Nevertheless we have received enough anecdotal evidence (see above, paragraphs 5.4, 20-22, 27-30) to convince us that cannabis almost certainly does have genuine medical applications, especially in treating the painful muscular spasms and other symptoms of MS and in the control of other forms of pain.

  8.3     We therefore recommend that clinical trials of cannabis for the treatment of MS and chronic pain should be mounted as a matter of urgency. We warmly welcome the fact that, in the course of our inquiry, both Dr Geoffrey Guy of GW Pharmaceuticals, and the Royal Pharmaceutical Society's working group under Sir William Asscher, have set off down this route (paragraphs 5.44-48). We welcome the Asscher group's intention to compare the effects of a standardised preparation of natural cannabis with those of the one synthetic cannabinoid already available, dronabinol, on the basis of the same dose level of THC.

  8.4     Although neither Dr Guy nor the Asscher group contemplate trials of smoked cannabis, we agree with the Chief Executive of the MRC that such a trial should not be ruled out (paragraph 5.57). However we recognise the dangers of smoking, and we do not envisage smoking being used to administer any medicine eventually licensed. For this reason we recommend that research be promoted into alternative modes of administration (e.g. inhalation, sub-lingual, rectal) which would retain the benefit of rapid absorption offered by smoking, without the adverse effects.

  8.5     The Government have said repeatedly that, if sufficient evidence in favour of cannabis as a medicine were produced for the MCA to be prepared to license it, they would amend the Misuse of Drugs Regulations so as to permit it to be prescribed. The problem with this policy is that it will take several years at least for this to happen. The Asscher group's trials are not expected to be complete before mid-2001, and will lead only to "proof of principle", leaving others to proceed with any pharmaceutical development. Dr Guy does not expect to receive a product licence in under five years. In the mean time, 85,000 people in this country will continue to suffer the very unpleasant symptoms of MS. Only a small proportion of these are known to have tried cannabis illegally; but of these, significant numbers report great relief of their symptoms. We do not believe that this position is satisfactory.

  8.6     We therefore recommend that the Government should take steps to transfer cannabis and cannabis resin from Schedule 1 to the Misuse of Drugs Regulations to Schedule 2 (see Box 3), so as to allow doctors to prescribe an appropriate preparation of cannabis, albeit as an unlicensed medicine and on the named-patient basis (see Box 6), and to allow doctors and pharmacists to supply the drug prescribed. This would also, incidentally, allow research without a special licence from the Home Office (see Box 8).

  8.7     It is argued in some quarters that some of those who campaign for medical use see it as a stalking-horse for the legalisation of recreational use (paragraphs 7.28-30). We do not see this as a reason to resist medical use if, as we believe, it is justified by the evidence. We prefer the argument recently advanced by Austin Mitchell MP in the House of Commons (14 January 1998, col. 317): at present, people who use cannabis for medical reasons are caught in the front line of the war against drug abuse. This makes criminals of people whose intentions are innocent, it adds to the burden on enforcement agencies, and it brings the law into disrepute. Legalising medical use on prescription, in the way that we recommend, would create a clear separation between medical and recreational use, under control of the health care professions. We believe it would in fact make the line against recreational use easier to hold.

  8.8     Before moving cannabis out of Schedule 1, the Government are required by law to consult the Advisory Council on the Misuse of Drugs. We recommend that they do so at once, and respond to this report only after receiving and considering the advice of the Council. We recognise that this may take longer than the time normally allowed for such responses.

Medical use of cannabinoids: recommendations

  8.9     Unlike cannabis itself, the cannabinoid THC (dronabinol) and its analogue nabilone are already accepted by the Government as having medical value (paragraphs 5.11-17)—producing the anomaly that, while cannabis itself is banned as a psychoactive drug, THC, the principal substance which makes it psychoactive, is in legitimate medical use. Some of our witnesses are prepared (paragraph 5.50) to contemplate wider medical use of the cannabinoids, but not of cannabis itself. We disagree, since some users of both find cannabis itself more effective (paragraph 5.51). We do, however, welcome the inclusion of THC in the trials proposed by the Asscher group, in like-for-like comparison with cannabis itself.

  8.10     Dronabinol (THC), though not licensed in this country, has already been moved to Schedule 2 to the Misuse of Drugs Regulations, and nabilone is a licensed medicine and not a controlled drug; so no Government action is required in either case to permit clinical trials or indeed prescription. All cannabinoids other than THC remain in Schedule 1, and transferring them would require agreement through the WHO under the 1971 Convention. We do not regard this as a priority, since we are not persuaded that any other cannabinoid has a convincing medical use; but we recommend that the Government should raise the matter of rescheduling the remaining cannabinoids with the WHO in due course, in order to facilitate research.

Why change the law?

  8.11     Our principal reason for recommending that the law be changed, to make legal the use of cannabis for medical purposes, is compassionate. Illegal medical use of cannabis is quite widespread (paragraphs 5.2-3); it is sometimes connived at and even in some cases encouraged by health professionals (paragraph 5.6); and yet at present it exposes patients and in some cases their carers to all the distress of criminal proceedings, with the possibility of serious penalties. We acknowledge that, if our recommendation were implemented, the United Kingdom would be moving out of step with many other countries; we consider that the Government should not be afraid to give a lead in this matter in a responsible way.

  8.12     As a secondary reason, we would observe that the law in this area appears to be being enforced inconsistently, and in some cases with a very light hand (paragraphs 7.2-5). Some cases are not brought to court; where users of cannabis for medical purposes have been prosecuted, the sentence has sometimes been light; and there have even been cases where juries have refused to convict. The Minister told us that he was content to leave this as a matter for the discretion of the prosecuting authorities and the courts (QQ 668-673). That is a constitutionally proper position for a Minister; but it is not the right position for Parliament. If statute law is not enforced, Parliament is brought into disrepute; either enforcement must be tightened up, or the law must be changed. In this case, we recommend the latter.

  8.13     A further subsidiary advantage of transfer from Schedule 1 to Schedule 2 would be the encouragement which this would give to research (paragraphs 7.18-26). There are exciting research opportunities in this field (see Chapter 3), which (on the basis of the number of grants by the MRC and the Wellcome Trust, and the number of Home Office research licences—paragraph 5.39 and Box 8) are not being fully taken up in this country, despite the excellence of British biomedical science. We are satisfied that the Home Office are not being deliberately obstructive; and we are glad that they have already taken up our proposal for a meeting between the research community and those responsible for the research licensing regime (paragraph 7.26). But, now that research in this field has taken off, and the existence of important medical applications is (in our view) well established, it is not appropriate for research to continue to be subject to this extra layer of administration. Transfer to Schedule 2 would also go some way to removing the stigma which many of our witnesses believe hangs over research in this field, deterring researchers, funding bodies, pharmaceutical companies and local ethics committees alike from involvement in research which might turn out to be of great importance.

  8.14     As the Minister pointed out to us, a doctor who prescribed cannabis on these terms, in the absence of a product licensed by the MCA for the relevant indication, would take on himself full responsibility for the consequences (Q 679). This is true. However we have received evidence from doctors who are currently prescribing nabilone on an unlicensed basis (Notcutt Q 405). We believe that the overwhelming majority of members of the medical profession can be trusted not to be reckless in this matter, and that the professional regulatory bodies will deal effectively with any who are.

  8.15     The Minister also observed that, in some cases, someone charged with a cannabis offence may claim medical use as a bogus defence or plea in mitigation (Q 674). We do not doubt that this happens at present; and, in the case of some people, it may be hard to tell where recreational use stops and medical use begins (paragraph 5.5). Rescheduling so as to permit prescription would in fact make this problem easier to deal with: rather than having to investigate individual medical histories, as at present, the authorities would simply ask to see the prescription.

  8.16     As with any medicine, there are some groups of patients for whom cannabis-based medicines will not be appropriate. On the evidence before us, cannabis-based medicines should not be prescribed for persons with, or predisposed towards, schizophrenic illness (paragraph 4.12) or cardiovascular conditions (paragraph 4.4); nor, pending further research, should they be prescribed for pregnant women (paragraphs 4.15-16). As with many medicines, users should be warned of possible effects on driving ability (paragraphs 4.6-9) and cognitive function (paragraph 4.13). As with any potentially addictive medicine, the risk of addiction (paragraphs 4.23-33) should be weighed up when deciding whether to prescribe, and the user should be warned. Therefore, if doctors are permitted to prescribe cannabis on an unlicensed basis, the medical professional bodies should provide firm guidance on how to do so responsibly (paragraph 7.17).

  8.17     As with any medicine which is open to abuse, safeguards must be put in place by the professional regulatory bodies to prevent diversion to improper purposes (paragraph 7.27). These might include a system of declarations to be signed by the doctor and the patient.

Recreational use

  8.18     It is believed in some quarters that the current absolute prohibition on the recreational use of cannabis and its derivatives is not justified by the adverse consequences for the user and the public. On the evidence before us, we disagree. On the contrary, we endorse the Government's statement in Tackling Drugs: "The more evidence becomes available about the risks of...cannabis,...the more discredited the notion that [it is] harmless" (paragraph 6.16).

  8.19     The harms must not be overstated: cannabis is neither poisonous (paragraph 4.3), nor highly addictive, and we do not believe that it can cause schizophrenia in a previously well user with no predisposition to develop the disease. However, we are satisfied that:

      —  It is intoxicating, enough to impair the ability to carry out safety-critical tasks (such as flying, driving or operating machinery) for several hours after taking (paragraphs 4.6-9);

      —  It can have adverse psychic effects ranging from temporary distress, through transient psychosis, to the exacerbation of pre-existing mental illness (paragraphs 4.10-12);

      —  Regular use can lead to psychological dependence (paragraphs 4.23-33); and, in some dependent individuals (perhaps 5-10 per cent of regular users), regular heavy use can produce a state of near continuous intoxication, making normal life impossible;

      —  Withdrawal may occasionally involve unpleasant symptoms (paragraphs 4.23-25);

      —  Cannabis impairs cognitive function during use (paragraph 4.6);

      —  It increases the heart rate and lowers the blood pressure, carrying risks to people with cardiovascular conditions, especially first-time users who have not developed tolerance to this effect (paragraph 4.4).

  8.20     Moreover, it is possible, though not proved, that the effects of cannabis on driving etc. may last longer than a few hours after taking (paragraph 4.7); that the damage to cognitive function may endure after withdrawal (paragraph 4.13); and that cannabis has adverse effects on the immune system (paragraph 5.16) and on fertility and reproduction (paragraphs 4.15-16).

  8.21     In addition, smoking cannabis carries similar risks of respiratory disorders to smoking tobacco. It is also possible, though not proved, that exposure to cannabis smoke increases the risk of cancers of the mouth, throat and lung (paragraphs 4.17-18).

  8.22     Therefore, on the basis of the scientific evidence which we have collected, we recommend that cannabis and its derivatives should continue to be controlled drugs.

Summary of recommendations

  8.23    

      (i)  Clinical trials of cannabis for the treatment of MS and chronic pain should be mounted as a matter of urgency (paragraph 8.3).

      (ii)  Research should be promoted into alternative modes of administration (e.g. inhalation, sub-lingual, rectal) which would retain the benefit of rapid absorption offered by smoking, without the adverse effects (paragraph 8.4).

      (iii)  The Government should take steps to transfer cannabis and cannabis resin from Schedule 1 to the Misuse of Drugs Regulations to Schedule 2, so as to allow doctors to prescribe an appropriate preparation of cannabis, albeit as an unlicensed medicine and on the named-patient basis, and to allow doctors and pharmacists to supply the drug prescribed (paragraph 8.6).

      (iv)  The Government should consult the Advisory Council on the Misuse of Drugs on this matter at once, and respond to this report only after receiving and considering their advice (paragraph 8.8).

      (v)  The Government should raise the question of rescheduling the remaining cannabinoids with the WHO in due course (paragraph 8.10).

      (vi)  If doctors are permitted to prescribe cannabis on an unlicensed basis, the medical professional bodies should provide firm guidance on how to do so responsibly (paragraph 8.16); and safeguards must be put in place by the professional regulatory bodies to prevent diversion to improper purposes (paragraph 8.17).

      (vii)  Cannabis and its derivatives should continue to be controlled drugs (paragraph 8.22).

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