Comment by Dr Katie Steele
Professor Nutt should be applauded for stressing that drug policy (education, penalties for misuse, police monitoring etc.) should be based on a transparent, evidence-based classification of drugs according to their harm. Moreover, his documented work on this issue is admirably sensitive to the complexity of the task—there are many facets to 'harm', and a variety of scientific experts and data sources must be consulted (see Nutt et al. 2007 in The Lancet). My concern is that, as the debate surrounding Nutt's dismissal intensifies in the popular media, his camp begins to exaggerate the role of the science advisor vis-à-vis the policy maker.
Several sources quote Nutt as saying "Most scientists would prefer an independent body that says 'these are the harms of drugs, we'll rate them on a classification system then you decide on what the appropriate penalties are'. Politicians cannot decide on harm, they can only decide on matters in their province". This statement is misleading, and not true to Nutt's own position in academic papers. The question is whether harm classification itself, before we even consider penalties for misuse, etc., involves social/political value judgments: if the answer is 'yes', then classifying drugs is not exclusively the domain of the scientist.
What counts as a 'benefit' or a 'harm' is sensitive to social values. For instance, should we consider the pleasurable effects of a drug harmful because they can lead to dependence? (Nutt and his colleagues do. They consider three main categories of harm, two pertaining to the individual—'physical' and 'dependence'—and an additional 'social' harm category. These are each further subdivided into three categories, of which 'pleasure' is one.) Even if there is broad agreement about the main categories of harm, there is still a question of their relative significance. For instance, what should we rate as more harmful: the long-term individual health problems caused by tobacco use, or social damage due to alcohol intoxication? Value judgments also subtly bear on inferences from evidence to harm scores. For example, if schizophrenia is regarded a really bad ailment, even poor evidence supporting a causal link between cannabis and schizophrenia may be deemed sufficient for a high score for this drug on the physical harm category.
Nutt's recent comments about the limited role for policy makers in the drug classification process are careless. This does nothing to absolve the government, however, for its apparent reluctance to engage in rational debate on the issue. Indeed, if the government wants to maintain that cannabis is, all things considered, more harmful than alcohol, then a rather sophisticated argument is required, given that experts rate alcohol as the more harmful drug on all the nine categories of harm considered by Professor Nutt and his colleagues.