Select Committee on Science and Technology Fifth Report

7  A scientifically based scale of harm?

Assessment of harm

92. We were interested to find out the criteria used by the ACMD in making its assessments of harm. The ACMD told us that Professor Nutt and his colleagues on the ACMD Technical Committee had developed a risk assessment matrix to evaluate the harms associated with different drugs (see Table 3). Professor Nutt said: "The matrix was developed when I was working on the Runciman Report because it became quite clear that we did not have any systematic way of conceptualising the range of harms and any way of properly categorising them and rating them […] When I became a member of the ACMD and Chairman of the Technical Committee, we set in process this procedure of getting all the members of the Technical Committee to work through in a systematic way the drugs".[187] The Minister, referring to the matrix, told us: "We have a scientific basis for determining harm. The ACMD refer to that when they classify drugs".[188] Table 3: ACMD Risk Assessment Matrix
Category Parameter
Physical harm Acute
Dependence Intensity of pleasure
Psychological dependence
Physical dependence
Social harms Intoxication
Other social harms
Healthcare costs

93. Professor Colin Blakemore pointed out, however, that it was not trivial to "decide what weighting to give to the different criteria for harm". We asked the ACMD to explain how it determined the weighting given to harm in each domain. In response, the ACMD stated: "using [the ACMD Risk Assessment] matrix, and assigning a score to each parameter (0 = no risk; 1 = some risk; 2 = moderate risk; 3 = extreme risk), Professor Nutt and his colleagues have developed an overall harm rating. They have not, as yet, attempted to weight individual parameters".[189] We welcome the initiative taken by the ACMD Technical Committee to develop a standard framework for the assessment of harm but we also note that determining harm scores using the matrix is almost as much an art as a science.

Current classifications

94. It is important to note that most of the current classifications of drugs were not decided on the basis of the risk assessment process described above. This is reflected in the conclusion drawn by the RAND report that "classification is not based upon a set of standards for harm caused by a drug; it varies depending on the drug in question".[190] DrugScope also told us: "there is no standard assessment tool or set of criteria of harm against which to match the different drugs".[191]

95. Although we have only examined a small number of drugs in any detail, we have identified a multitude of anomalies in decisions about their classification. Fresh magic mushrooms were placed in Class A despite the lack of evidence that this reflected the harms associated with their misuse. They were put there because the chemicals which they contain, psilocin and psilocybin, were already there, but there was also a lack of evidence to justify these chemicals being placed in Class A. By contrast, the ACMD argued that it could not review the Class A status of ecstasy because there was insufficient evidence. In addition, while on the one hand psilocin and psilocybin appear to be used rarely (if ever) as hallucinogens, the ACMD argued, on the other, against the movement of methylamphetamine to Class A on the grounds that there was no evidence of widespread usage. In the case of methylamphetamine, the ACMD also suggested that moving it to Class A could increase its appeal—an argument which if invoked more widely could be used to counter any proposal to move a drug to a higher Class. It is perhaps not surprising that Professor Colin Blakemore's view of the classification system was that "It is antiquated and reflects the prejudice and misconceptions of an era in which drugs were placed in arbitrary categories with notable, often illogical, consequences".[192]

96. Furthermore, a paper authored by experts including Professor Nutt, Chairman of the ACMD Technical Committee, which we have seen in draft form, found no statistically significant correlation between the Class of a drug and its harm score as calculated by leading experts using the so-called Delphi method.[193],[194] Astonishingly, despite the fact that Professor Nutt is the lead author, the paper asserted that "The current classification system has evolved in an unsystematic way from somewhat arbitrary foundations with seemingly little scientific basis".[195] The paper also found that the boundaries between the Classes were entirely arbitrary and the authors argued that the rigid nature of the classification system made it difficult to move substances between Classes as new evidence emerged.

97. Considering the fact that the Chair of the ACMD Technical Committee had started drafting the paper proposing an alternative to the ABC system of classification more than 18 months ago, we were very surprised to hear from the Chairman of the ACMD that the Council had "never formally discussed the case for reviewing the classification system".[196] We were also taken aback by Sir Michael's assertion that the Council did not possess "the necessary expertise" to provide advice on alternative approaches to the classification of drugs. In addition, confidential information we have obtained makes us somewhat suspicious of the reasons behind the delay in submission of the paper authored by Professor Nutt and his colleagues for publication. We understand that the ACMD operates within the framework set by the Misuse of Drugs Act 1971 but, bearing in mind that the Council is the sole scientific advisory body on drugs policy, we consider the Council's failure to alert the Home Secretary to the serious doubts about the basis and effectiveness of the classification system at an earlier stage a dereliction of its duty.

Review of the classification system

98. On 19 January 2006, following his statement on the classification of cannabis, the then Home Secretary Charles Clarke announced that he was initiating a review of the ABC classification system:

"The more that I have considered these matters, the more concerned I have become about the limitations of our current system. […] I will in the next few weeks publish a consultation paper with suggestions for a review of the drug classification system, on the basis of which I will make proposals in due course."[197]

The decision to review the classification system was supported by the ACMD and others. Sir Michael Rawlins told us in oral evidence: "I think it right that the Home Secretary is relooking at it".[198] Martin Barnes, Chief Executive of DrugScope and member of the ACMD, also told us: "I think the fact that the Home Secretary has announced a review is very welcome" and argued that the review should be as wide ranging as possible: "obviously the wider, the more clean slate it starts the better".[199] Mr Barnes further noted that this provided "an opportunity […] to address those issues of over the counter medicines but also the substances that are not currently classified that can be bought on Camden High Street or on the Internet".[200]

99. Professor Blakemore, Chief Executive of the MRC, indicated that he supported the decision to undertake a review, suggesting that "the driver for the review was quite clearly the time, effort, deliberation and conflicting advice that impinged on the decision not to re-classify cannabis, and the realisation that the arbitrary (and I would defend that word) boundary between B and C was not easily defensible". Professor Blakemore asked: "If it took so much effort to consider one particular drug and whether it should be placed on one side or other of a boundary, does it not imply that the entire mechanism for classifying requires a new look?".[201]

100. We too welcomed the announcement by the then Home Secretary that he would be reviewing the entire classification system. However, we became concerned that the promised "few weeks" between the announcement and the publication of the consultation turned into several months. Furthermore, following the ministerial changes at the Home Office, Vernon Coaker told us: "with respect to the consultation document which is in draft form in the department, the view is that we will need to wait until such time as we decide how to proceed with respect to the review of the classification system and also, similarly, wait for the report of this Committee - which we want to take into account in determining the best way forward".[202] We urge the new Home Secretary to honour his predecessor's promise to conduct the review—our findings suggest that it is much needed. Although we are, of course, pleased that the Home Office is placing such store by our recommendations, the long delay in publishing the consultation paper on the review of the classification system has been unfortunate and should be rectified immediately.

Relationship between classification and penalties

101. We were interested to hear that the police only use the classification system as a rough guide in carrying out their duties. Andy Hayman, Chair of the ACPO Drugs Committee, was of the view that the anomalies in the classification system did not matter, asking: "why should we get too hot under the collar about it?". He argued that a classification system was useful "to direct effort" in health services and policing but since the police could use their discretion in determining their responses, it was not a problem that the classification system was "pretty crude".[203] Jan Berry, Chair of the Police Federation, has also commented: "We have repeatedly said you do not need to change classification to change the way drug issues are policed. It's important that police officers have discretion to take account of all individual circumstances".[204] In addition, we heard in the US that the lack of a direct link between Schedules and penalties gave the police the freedom to focus resources as they saw fit. Nevertheless, Professor Blakemore warned that "If the placement of the drug in [a specific] category is only rough and if it is not particularly rationally assessed then the attitudes to society and the media and politicians are misplaced".[205]

102. The dismissive tone adopted by the Chair of the ACPO Drugs Committee in giving evidence to this inquiry was disappointing, but his lack of concern over the classification system was also revealing. We have already noted that the purpose of the classification system is to ensure that the penalties for possession and trafficking are proportionate to the harmfulness of the particular substance (paragraph 78). The fact that the classification system is of such minor importance to the police suggests that it is not fit for purpose. This being the case, it also seems surprising that so much effort was made to get the classification of cannabis 'right'. We recommend that the Government make this de facto relationship more explicit and decouple the ranking of drugs on the basis of harm from the penalties for possession and trafficking.

103. It would clearly be impractical to have a classification system directly linked to penalties in which the ranking of drugs changed frequently in response to new evidence. Decoupling penalties and the harm ranking would permit a more sophisticated and scientific approach to assessing harm, and the development of a scale which could be highly responsive to changes in the evidence base. It is beyond the scope of this inquiry to recommend an alternative approach to determining penalties but we note that possibilities could involve a greater emphasis on the link between misuse of the drug and criminal activity or make a clearer distinction between possession and supply. It should also be noted that while it is certainly possible—and desirable—to take a more evidence based approach to ranking drugs according to harm associated with their misuse, as highlighted in paragraph 93, caution needs to be exercised in viewing the scale as 'scientific' when the evidence base available is so limited and, therefore, a significant part of the ranking comes down to judgement calls.

Benefits of a more scientifically based scale of harm

104. The caveats about the limitations of the evidence base notwithstanding, a more scientifically based scale of harm than the current system would undoubtedly be a valuable tool to inform policy making and education. Charles Clarke, the then Home Secretary, pointed out that: "One of the biggest criticisms of the current classification system is that it does not illuminate debate and understanding among the young people who are affected by it".[206] Lesley King-Lewis, Chief Executive of Action on Addiction, also called for "a much more rational debate" which would inform "young people in particular, of the different levels of drugs and the different and varying harms that they can do to themselves".[207] Sir Michael Rawlins, ACMD Chair, agreed, saying: "Where I think we are all at fault, not just the ACMD but all of us are at fault, is not being better at explaining to young people particularly the dangers of drugs".[208]

105. Professor Nutt, Chair of the ACMD Technical Committee, argued that a more scientifically based scale of harm would be of value in this situation: "in education the message has to be evidence based. If it is not evidence based, the people you are talking to say it is rubbish".[209] The Runciman report also noted that "The evidence that we have collected on public attitudes shows that the public sees the health-related dangers of drugs as much more of a deterrent to use than their illegality", emphasising the importance of conveying health risks and harms as clearly and accurately as possible.[210] It is vital that the Government's approach to drugs education is evidence based. A more scientifically based scale of harm would have greater credibility than the current system where the placing of drugs in particular categories is ultimately a political decision.


106. One of the most striking findings highlighted in the paper drafted by Professor Nutt and his colleagues was that fact that, on the basis of their assessment of harm, tobacco and alcohol would be ranked as more harmful than LSD and ecstasy (both Class A drugs).[211] The Runciman report also stated that, on the basis of harm, "alcohol would be classed as B bordering on A, while cigarettes would probably be in the borderline between B and C".[212] Various memoranda argued that the exclusion of tobacco and alcohol from the classification system was an anomaly. Transform Drug Policy Foundation told us: "It is this omission from the classification system that, perhaps more than any other, truly lays bare its fundamental lack of consistency, reasoning or evidence base" on the grounds that together tobacco and alcohol cause "approximately 40 times the total number of deaths from all illegal drugs combined".[213] In our view, it would be unfeasible to expect a penalty-linked classification system to include tobacco and alcohol but there would be merit in including them in a more scientific scale, decoupled from penalties, to give the public a better sense of the relative harms involved.

187   Q 174 Back

188   Q 1201 Back

189   Ev 103, 104 Back

190   RAND Report, Executive Summary Back

191   Ev 91 Back

192   Professor Colin Blakemore, A Scientifically Based Scale of Harm for All Social Drugs, An Interdisciplinary Perspective on Alcohol and Other Recreational Drugs: Conference Proceedings, The Beckley Foundation, 2003 Back

193   Draft provided in confidence by Professor Nutt on behalf of the authors. Back

194   The Delphi Method generally involves a structured process for collecting and distilling knowledge from a group of experts using of a series of questionnaires interspersed with controlled opinion feedback. Back

195   As above Back

196   Ev 104 Back

197   HC Deb, 19 Jan 2006, col 983 Back

198   Q 115 Back

199   Q 440 Back

200   As above Back

201   Q 393 Back

202   Q 1205 Back

203   Q 380-1 Back

204   Plans to toughen drugs law 'only sow confusion', The Times, 8 June 2006 Back

205   Q 386 Back

206   HC Deb, 19 Jan 2006, col 992 Back

207   Q 465 Back

208   Q 167 Back

209   Q 197 Back

210   Runciman Report, para 8 Back

211   Draft provided in confidence by Professor Nutt on behalf of the authors. Back

212   Runciman Report, para 40 Back

213   Ev 64 Back

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