Revisiting the David Nutt debate: Is it possible to rank different drugs by the harm they cause?

September 6, 2011

The scientific and political worlds were transfixed in late 2009 when UK drugs advisor Dr. David Nutt was sacked by Home Secretary Alan Johnson for his controversial views on the harmfulness of different drugs and the lack of evidence behind current drug policy, views first publicised in a Lancet report in 2007.1 Scientists at the time were unanimous that scholarly research such as Nutt's should not be subject to political attack, but a new article in the scholarly journal Addiction points out a more rational basis for criticizing Nutt's work on the harmfulness of drugs: it is scientifically flawed.

American researchers Jonathan Caulkins, Peter Reuter, and Carolyn Coulson argue that Nutt erred by assuming that drug-related harms can be reduced to a single dimension. Most such rankings combine individual harms and harms to society. But national policies aim to reduce harm to society, so combined scores may be misleading. Furthermore, it is not for scientists alone to decide the relative weights society should place on such disparate drug-related harms as dependence, overdose death, and corruption. Caulkins and colleagues also argue that even perfect ratings of substances' current harm to society would not be useful, because harm is governed by the interaction between substance and policy; it is not a property of the chemical alone. Policymakers need that show the likely changes in different types of harm associated with each change in drug policy.

Addiction hosts a spirited international debate about these critiques, including a response from Dr. Nutt himself.

Canadian researchers Benedikt Fischer and Perry Kendall argue that there is no benefit to categorically knocking down the work of Nutt and his colleagues when current global drug control policy pays scientific evidence no heed. The primary problem at hand is to get governments to pay attention to the evidence for drug policies, not to develop more complex rankings that will be ignored. Fischer and Kendall state, "If we assume public health and welfare should be guiding principles for substance control policy, we would not expect to see the third most commonly used drug (cannabis) to be scheduled and regulated alongside drugs like heroin and cocaine, while alcohol and tobacco are not only legally available, but are openly traded and lead to thousands of cases of deaths and injuries each year."

This view is supported by Norwegian researcher Ingeborg Rossow. She argues that Norwegian policymakers' views reflect those of the general public: illegal substances constitute a larger problem than alcohol, which justifies strict control of illegal drugs and liberalization of alcohol control. Addiction researchers know that legal substances (alcohol, tobacco, prescription drugs) are as much a problem as illegal substances, but getting the public to recognize this fact is difficult. Publicising reports on the relative size of harms from legal and illegal substances may help to change public opinion.

Australian researcher Robin Room argues that all national drug schedules are based on two outdated, pharmacologically-based international drug treaties from 1961 and 1971. By ranking drugs in the light of changes in knowledge and understanding since then, Nutt and colleagues have "started a debate which is long overdue."

"The priority of the debate" Room argues, "should be on the official schedules and what to do about them."

Isidore Obot, a Nigerian researcher, embraces the idea of developing more complex policy tools, because more refined ranking systems will produce more useful information for policymakers. The value of the model developed by Nutt and colleagues lies in the improvements future researchers will make to it.

David Nutt's defence is expressed in his Voltairian title, "Let not the best be the enemy of the good." Nutt accepts that the 2007 harm-ranking model is imperfect but argues that it is nonetheless a good attempt to use scientific evidence in drug policy. Says Nutt: "we have provided the best currently available analysis of an extremely complex multifaceted data set. It ain't perfect but is nevertheless good enough to be useful." Nutt also explains that his simplified look at drug harms provides policymakers with a tool of the type they use: "All decisions regarding drug classifications resolve harms into a single scale point for each drug, so people, particularly politicians, are used to making and working with such estimations."

Caulkins, Reuter, and Coulson respond by restating that the current methods of ranking drugs by harm are conceptually and methodologically unsound. Defending them on the grounds that that simplification is required is equally unsound. We need better methods for understanding the complex network of individual and aggregate harms. "[If] the public has trouble grasping multi-dimensional scales, that should be seen as a hurdle to overcome, not a restraint that needs to be accepted."

The final word should perhaps go to Fischer and Kendall, who argue that any country that uses these admittedly flawed and limited harm scales to inform public policy will experience a "quantum leap of progress" toward evidence-based drug policy. They state that "The benefits from grounding drug control policy in Nutt et al.'s harm scales could be expected to be tangible and last until well after their critics have revised and improved them."

More information: 1 Nutt D., King L.A., Saulsbury C., and Blakemore C. Development of a rational scale to assess the harm of drugs of potential misuse. Lancet 2007;369:1047-53.

Related Stories

Recommended for you

Exploring the potential of human echolocation

June 25, 2017
People who are visually impaired will often use a cane to feel out their surroundings. With training and practice, people can learn to use the pitch, loudness and timbre of echoes from the cane or other sounds to navigate ...

Team eradicates hepatitis C in 10 patients following lifesaving transplants from infected donors

April 30, 2017
Ten patients at Penn Medicine have been cured of the Hepatitis C virus (HCV) following lifesaving kidney transplants from deceased donors who were infected with the disease. The findings point to new strategies for increasing ...

'bench to bedside to bench': Scientists call for closer basic-clinical collaborations

March 24, 2017
In the era of genome sequencing, it's time to update the old "bench-to-bedside" shorthand for how basic research discoveries inform clinical practice, researchers from The Jackson Laboratory (JAX), National Human Genome Research ...

The ethics of tracking athletes' biometric data

January 18, 2017
(Medical Xpress)—Whether it is a FitBit or a heart rate monitor, biometric technologies have become household devices. Professional sports leagues use some of the most technologically advanced biodata tracking systems to ...

Financial ties between researchers and drug industry linked to positive trial results

January 18, 2017
Financial ties between researchers and companies that make the drugs they are studying are independently associated with positive trial results, suggesting bias in the evidence base, concludes a study published by The BMJ ...

Best of Last Year – The top Medical Xpress articles of 2016

December 23, 2016
(Medical Xpress)—It was a big year for research involving overall health issues, starting with a team led by researchers at the UNC School of Medicine and the National Institutes of Health who unearthed more evidence that ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

neiorah
not rated yet Sep 06, 2011
alcohol and nicotine should be in the same class as heroin and cocaine

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.