The drug scheduling debate: The view from Vienna

Drug scheduling is the process of sorting controlled substances into categories, generally with the purpose of assigning higher levels of control over those drugs viewed as most hazardous. This implies a process of weighing the respective dangers and benefits of each drug, an undertaking of considerable complexity. As with many controversial topics, members of the public, and especially specialised academics, may feel that their opinions are not given enough credit. This is particularly true for popular drugs with vocal supporters, such as cannabis. Ted Leggett.

There are as many mechanisms for evaluating drug harmfulness as there are agencies involved in the regulatory process. They must all confront certain core questions. One is the mechanism for arriving at a decision. Who gets to vote, and how are decisions reached? Another is the criteria to be used in justifying decisions made. How is 'harmfulness’ to be evaluated?

Many have argued that the process of drug scheduling could be improved, but exactly what this would look like remains controversial. The difficulties of scheduling drugs through scientific consensus were highlighted in a provocative article in The Lancet, entitled ‘Psychoactive drugs of misuse: rationalising the irrational’.

The article argues that, in the United Kingdom, ‘The current classification system has evolved in an unsystematic way from somewhat arbitrary foundations with seemingly little scientific basis’.

It suggests an alternative model, in which experts from a range of disciplines meet and rank drugs based on a number of pre-selected criteria.The rankings are then averaged to produce a ‘mean harm score’, which the authors suggest should be associated with scheduling. The article then describes an attempt by the authors to implement that approach and the results it produced.

While such scientific input should undoubtedly be part of the scheduling process, and evaluations of the sort conducted by the authors should be encouraged, the devil is in the details. In the experiment, the key question of who was doing the evaluating is left vague, and the reasons behind refusals and dropouts are not well described. Not every expert rated every substance parameter, and the reasons for abstentions are unclear. Efforts were made to achieve a consensus, including a revision process in which outlier scores were challenged. The participants were also given review articles, including some by the authors of the research themselves. In the end, the study seems mainly to demonstrate the ability of the authors to guide a select group of authorities to a reasonably consistent position.

Despite a well thought out scheme of criteria, the question of how to evaluate harm also poses considerable difficulties. Many of these centre on the combination of two distinct types of assessment parameters, one dealing with harm to the individual and the other dealing with harm to society at large. Social harms are directly related to the availability of each substance. As the authors themselves note, ‘direct comparison of the scores for tobacco and alcohol with those of other drugs is not possible since the fact that they are legal could affect their harms in various ways, especially through easier availability’.

However, this is precisely what they proceed to do, placing both sets of drugs on the same scale and even suggesting an appropriate scheduling for alcohol and tobacco. As a result, Associated Press coverage of this article proclaims, ‘Booze and smokes more dangerous than some illegal drugs’. While this is clearly not the intent of the article, it is a predictable misreading of the results.

Two-thirds of the assessment parameters are types of harm to individuals, and one-third relate to social harm, an implicit weighting that is never justified, giving dangerous but rarely used drugs a higher overall harmfulness rating than commonly used ones. For example, ketamine, a drug used irregularly even among dedicated clubbers, is rated higher in overall harmfulness than cannabis, a drug used by nine per cent of the adult population of the United Kingdom every year, many on a daily basis. Whatever the value of this ranking to scheduling, the authors say they offer these rankings to provide guidance on relative risks so that resources can be more rationally distributed with regard to substance-specific interdiction, education and treatment. Of course, it would make little sense to dedicate as many resources to ketamine as to cannabis, despite the fact that social harms were theoretically included in the overall harmfulness ranking.

Weighting among individual parameters is also troubling. For example, while the types of physical harm of the drug to individuals would seem to be covered by the two assessment parameters of ‘acute harm’ and ‘chronic harm’, a third harm parameter – the potential for intravenous injection – is included. This gives excessive weight to drugs that can be injected, without taking into consideration the prevalence of injection for that drug type. For example, cocaine is given the same injection harm rating as heroin (the highest possible rating), despite the fact that injection is more common among heroin users than cocaine users. If injection were removed from the physical harm assessment, cocaine would be deemed scarcely more harmful than alcohol. Even LSD gets a mild boost due to its alleged potential for injection, a practice that, if it occurs, is extremely rare.

It should also be noted that the results are specific to the United Kingdom and cannot be generalised internationally. This is obvious for types of social harm, which are reflective of the extent of use – methylphenidate abuse would not figure in tallying the impact of drugs in most countries of the world. However, this social bias is also true of the harm to individuals caused by specific drugs. The low rate of physical harm attributed to solvent use, for example, can only be based on the way solvents are most commonly used in the UK, which is to say light recreational use. In developing countries, solvents are used by some groups, such as street children, on a continuous basis, and the impact on health is devastating. The fact that the author’s ranking of drugs corresponds to that of studies conducted in other national contexts is offered in validation of the findings. Rather, it should draw suspicion, as it suggests that the study was less an independent inquiry into the specific types of harm experienced in the UK than a reflection of popular views on the relative harmfulness of these substances.

These concerns highlight the difficulties of objectively assessing the relative risks of drugs, particularly on an international basis. Specialists in many fields would like to see public policy decisions made by a referendum among experts, but the practicalities of this process are problematic. While there remains potential for developing this approach, and expert opinion will continue to be an important part of a complex evaluation, the question of who gets a say and how they should evaluate risk will remain at the core of the controversy.

Ted Leggett is a Research Officer with the Vienna-based UN Office on Drugs and Crime.

First published in Drugs and Alcohol Today Volume 7, Issue 3, October 2007. Reprinted with permission.