Debunking the drug myths

Ill-informed opinions rather than facts have shaped the public debate about drugs and their effects, and for far too long, argues David Nutt.

David Nutt. Sketch: Dan Murrell/New Statesman

All our politicians want for Christmas is to know what you think. They are supposed to represent the public, but they must constantly battle to balance their own views with the evidence, as well as pressure from the media, industry and interest groups, all the while desperately chasing public opinion.

So, faced with such a barrage of conflicting interests, what is a politician to do? His first duty must be to the electorate, so he might first try to gauge public opinion. Luckily, there are many organisations that have helpfully carried out surveys into what people think –or, at least, what people think about a particular issue when asked in a particular way.

Questions, and how they are asked, make a difference. The British Lung Foundation led its media campaign this past June with the claim that public opinion on cannabis is alarmingly relaxed compared to the “evidence” on the harms of cannabis to the lungs. The foundation trumpeted its survey finding that, “in stark contrast to evidence”, “88 per cent of people think a typical tobacco cigarette puts you at greater risk of developing lung cancer than a typical cannabis cigarette”.

Matters of fact

This is an unevidenced result, being used to push a misguided agenda, based on misinterpreted evidence. Cannabis and tobacco cannot be compared meaningfully on a joint-to-cigarette basis. Comparing the risks of drugs requires evidence about the effects of their use on their users; the cancer risk is not located in the inert bundle of plant material wrapped in paper. The typical cigarette smoker gets through a dozen cigarettes a day; some use three times that. Virtually all daily smokers are addicted.

By contrast, less than a quarter of cannabis users within the European Union use daily, of whom about 40 per cent, studies suggest, are likely to be dependent. Tobacco smoking poses a grave risk of cancer, as does smoking cannabis with tobacco, both habits that the British Lung Foundation should work urgently to minimise. Smoking cannabis without tobacco may cause wheezing and coughing, but so far the link with lung cancer has not been proved definitively.

Another approach is to disregard the evidence altogether and base one’s decisions on personal belief. When a constituent of Jeremy Hunt, now the Secretary of State for Health, challenged him in 2007 to explain why he was supporting an early-day motion in favour of homoeopathy, he kindly wrote a letter back recognising the constituent’s “view” that homoeopathy has been shown conclusively not to work but maintaining that his own “view” is different.

Whether homoeopathic medicine works better than sham treatment with “normal” water is not a matter of “views”, it is a matter of evidence. Hunt’s position shows the desperate need in parliament for a better understanding of evidence. It is entirely legitimate (whether correct or not) for a politician to defend homoeopathy on the National Health Service on the grounds that there is significant public demand, that prescribing shaken water could keep prescription charges down as medicine budgets rise, or that a convincingly presented fake medicine can make people feel better.

It is also entirely legitimate for Hunt to criticise the extensive research showing that homoeopathy does not work – although I would like to see him try. But it is corrosive to the political process when people can keep repeating factually incorrect statements under the protection of the notion that “everyone is entitled to their opinion”.

When public and political opinion flies in the face of evidence, such as Gordon Brown’s assertion that skunk is “lethal”, it needs scrutiny. The ability to work together to find consensus about how to regulate drugs in a democracy is damaged by the prevalence of mistaken beliefs.

Blinded by bilge

We should be open and clear about morals if we want an effective political process to reduce harms, because everyone is entitled to an opinion on drug morality, personal responsibility, liberty, spirituality, and so on. There are, however, issues in which we would not wish public opinion and/or the beliefs of individuals to be the deciding factor: public and political opinion rightly plays, at most, a supporting role in the purely scientific questions of medical diagnosis and treatment. Dangerous outbreaks of measles have followed panics over the MMR vaccine driven by the media. All too often, the public is bombarded by statements from polit - icians and the media which show no understanding of the science.

In a perfect world, where people’s views evolved in the light of developing evidence, change would be less sluggish. In reality, where perspectives on drugs are highly politicised, opinions can appear entrenched. Generational replacement is bringing forth a cohort that encounters more diverse representations of drug users, as victims as well as villains. The younger generation can debunk a drug myth with a few clicks of a mouse and is generally more tolerant of other people’s lifestyle choices.

There is an intrinsic tension between opinion (public or political) and evidence that needs to be acknowledged openly. Opinion is tightly bound up with moral, social and political identity, and broadly we consider it a merit to stick to our opinions, so society can get stuck with them beyond their best-before date. So how can we foster a public and political environment that can produce good drug policy?

We need to be more open about being motivated by values and morals. We need to have a clear demarcation of the discussion over protecting public morality and minimising harm. When we are talking about the latter, opinions should be under scrutiny to ensure that they are evidence-based. Then we might finally see harmony between public opinion and evidence.

David Nutt is the Edmond J Safra Professor of Neuropsychopharmacology at Imperial College London