Sending messages through drug classification

A flawed belief in the principle of deterrence underpins the Misuse of Drugs Act’s classification system, which was considered groundbreaking back in 1975.

In theory, the classification system is designed to associate greater legal risks with harder drugs that cause more damage for society and people who use drugs.

Of course, for a classification system to be effective, people using or selling the drug must be aware of the classification and its punishments. There is scarce research in New Zealand or elsewhere that proves that this is the case.

The classification of drugs is intended to be evidence-based. The Expert Advisory Committee on Drugs (EACD) makes recommendations to the Minister of Health based on factors including the likelihood of abuse, risk to public health, ability to create dependence and the classification decisions made by other countries.

In 2003, on EACD advice, the government reclassified methamphetamine from Class B to Class A. The Police Minister noted in November 2008 that, since then, the methamphetamine industry has grown. Despite a legal system designed to deter use, it would appear that industry participants perceive the rewards associated with methamphetamine creation and use as higher than the risks of legal sanction.

One apparent goal of pegging classifications to penalties is to deter somebody who tries a Class C drug like cannabis from moving ‘up’ to a Class A drug like methamphetamine.

Although most New Zealanders who have tried cannabis have not gone on to harder drugs, there is a widespread notion that Class C drugs – cannabis in particular – can serve as a ‘gateway’ to other drugs.

Indeed, this belief is consistent with American research that shows the use of cannabis is roughly associated with a stronger likelihood to try cocaine or psychedelics later. On the other hand, there is no evidence that the use of, say, ecstasy (a Class B drug in New Zealand) is followed by greater likelihood of using heroin (Class A). Research published in the Journal of Policy Analysis and Management concludes that the gateway concept remains controversial because a causal link between trying cannabis and trying harder drugs has not actually been established. This supports New Zealand research showing such ‘pathways’ exist, but that the ways they work are unclear.

The classification approach has been adopted in many countries. In the United States, drugs are divided into five schedules, but different states have their own legislation for scheduling drugs and for punishments. This means that one drug like ecstasy has different classifications and different punishments in different legal environments, which must undermine the deterrent effect.

In the United Kingdom in 2006, the House of Commons Science and Technology Committee took a close look at that country’s drug classification system and the workings of its equivalent to the EACD. The United Kingdom system is very similar to that of New Zealand: it has a three-tier drug ranking system of Class A, B and C.

The committee was troubled by the lack of research anywhere into such a system’s effectiveness. It cited evidence from the Chair of the Association of Chief Police Officers Drugs Committee that, “I cannot envisage any user – a dependent drug user, that is – having any kind of thought as to whether it was a Class A, B or C drug they were consuming.”

At the very least, this points to an information problem: if people who use drugs are not informed of the legal risks associated with different drugs, the deterrence effect will be fuzzy.

There is even anecdotal evidence that some people might see a Class A classification as an incentive to try a particular drug.

The committee was not sold on the argument that a classification system sends out ‘signals’ to drug users or potential drug users. Based on reported ballooning drug use in the United Kingdom, the committee felt that using the criminal justice system to send out public health messages about drugs was, at best, inefficient.

In the United Kingdom, the process by which drug classification decisions are made is often undisclosed and can be ill-defined, opaque and seemingly arbitrary. While New Zealand’s EACD goes to some lengths to promote transparency, the classification of drugs remains more of an art than a science.

In theory, three main factors determine the harm associated with any drug: the physical harm that the drug causes the individual user, the tendency of the drug to induce dependence and the effect of the drug’s use on families, communities and society.

In some cases, this is straightforward. Drugs that can be taken intravenously – such as heroin – carry a high risk of causing sudden death from respiratory depression and therefore score highly on any metric of harm. Methamphetamine also carries the risk of heart failure and seizures, and long-term chronic use can cause psychosis, aggression and violent behaviour. Cocaine induces very powerful dependence because higher doses are needed to obtain the same effect over time and because they create intense cravings and withdrawal reactions.

On the other hand, so does nicotine, which is a legal drug, and hallucinogens do not encourage physical dependence or carry a massive risk of causing sudden death, yet rate highly on both the United Kingdom and the New Zealand classifications. Because the longer-term effects of newer drugs like ecstasy are unknown, they can be difficult to classify.

Harm to society can be caused by many factors, including the damage to family and social life, as well as the costs to the health, social and justice systems. It is interesting to note that a legal drug – alcohol – creates a lot of accidental damage to users and to property through drunken behaviour and car crashes, while tobacco incurs higher costs on the healthcare system than any other drug.

In 2007, a research paper published in The Lancet used a group of independent drug addiction experts to attribute mean harm scores to illegal and legal drugs. One author of the paper was the chairman of the committee that recommends drug classification decisions to the British government.

“The results of this study do not provide justification for the sharp A, B or C divisions of the current classifications,” the researchers concluded. “Neither the rank ordering of drugs nor their segregation into groups… is supported by the more complete assessment of harm described here.”

From a scientific perspective, the researchers noted, the exclusion of alcohol and tobacco from the Misuse of Drugs Act was arbitrary.

The addiction professionals rated the drugs in the following order: heroin, cocaine, barbiturates, street methadone, alcohol, ketamine, benzodiazepines (e.g. Valium), amphetamine, tobacco, buprenorphine (e.g. the painkiller Temgesic), cannabis, solvents, 4-methylthioamphetamine, LSD, methylphenidate (e.g. Ritalin), anabolic steroids, GHB, MDMA (ecstasy), alkyl nitrates, khat.

The House of Commons Science and Technology Committee concluded there are startling differences between this ranking and that of the United Kingdom’s Misuse of Drugs Act. The same conclusion is reached when it is compared with New Zealand’s ranking.

One of the research paper authors told the select committee that the classification system “is antiquated and reflects the prejudice and misconceptions of an era in which drugs were placed in arbitrary categories with notable, often illogical consequences.” Even the Association of Chief Police Officers acknowledged that the classification system was “pretty crude”.

The committee recommended that the government decouple the harm ranking of drugs from the penalties for possession and trafficking. This would allow a more sophisticated and scientific approach to assessing harm and the development of a scale that would be responsive to new research.

The committee pointed out that a more scientifically based scale of harm would have greater credibility than a system where the placing of drugs in a particular category is ultimately a political choice.

Relying on politicians to make decisions about drug classifications can lead to science being overruled by short-term concerns such as media attention. The British system’s credibility was undermined between 2000 and 2007 when five successive Home Secretaries all sought to readdress the classification of cannabis amid a heated public debate. Eventually, the UK government ignored its scientific advisors’ recommendations and re-classified the drug.

Under our similar system, the same thing could occur in New Zealand. While we have not been engaged in a heated and politicised debate on cannabis recently, this is perhaps largely because successive governments have agreed in coalition deals not to revisit its legal status. This, in itself, has largely cut off the potential for evidence-based scientific input to public discourse.

Another advantage of decoupling the scientific harm metric from penalties would be that tobacco and alcohol could be included in a scientific scale to provide the public with a better sense of the relative harms involved with different drugs, legal or otherwise.