As you may know, earlier this month I gave evidence to the Home Affairs Select Committee’s (HASC) current inquiry into drugs. We had a wide-ranging discussion across many aspects of alcohol and drug harms particularly in relation to the value of drug law reform and decriminalisation. (You can watch the session, including the interesting evidence of the subsequent witnesses online). I strongly believe that we should focus on public health approaches to the drug problem, and decriminalise the possession of drugs for personal use, for the following simple reason;- If users are addicted then they are ill, and criminal sanctions are an inappropriate way to deal with an illness. If they are not addicted then criminalisation will almost always lead to greater harms to the user than the effects of the drug. For example, it can severely limit career options in public service and prevent travel to some countries particularly the USA.

However, it was clear from questions from several of the HASC committee that they are very frightened that reducing or removing the criminal penalties for drug possession will lead to greater use – and then greater harms overall.  This is a reasonable hypothesis. Forming hypotheses represents the first step in thinking scientifically. Next, we should test the hypothesis against the available evidence. I think that the following evidence allows us to reject this hypothesis.

1.    There is good evidence that decriminalisation does not radically increase drug use and can reduce some measures of harm, as shown by a balanced review of the first ten years of the Portugal experience of decriminalisation. The collapse of society predicted by some did not occur; they had slight increases in drug use followed by slighter falls, which compares favourably with the trends in the neighbouring countries and the rest of the EU over the same period. More importantly, young people growing up under this system used fewer drugs, and harms and deaths from heroin went down as a result of a treatment-centred attitude replacing a punishment-centred approach. Remarkably, young people who have grown up in the Netherlands, where cannabis use is decriminalised, are less likely to be users of the drug than young people in Britain, the US and many other countries which criminalise young users. Perhaps the cachet of illegality here promotes some use.

2.    An increase in the availability of some drugs may actually lead to a reduction in the use of other more harmful drugs, so reducing net harms to society. We saw a noteworthy example of this in the past few years with the advent of the stimulant mephedrone. As this became popular, cocaine users seem to have switched to mephedrone and cocaine deaths fell by almost a quarter. Mephedrone gives a strong high and has potential to harm and kill, but seems much less likely to kill than cocaine. By switching, cocaine users reduced their risk of dying. It appears that the mephedrone phase caused the first significant impact on the steady rise of cocaine deaths we had seen in 20 years. It seems to have been a major – if unplanned and temporary – public health success. Relatively fewer young people progress to problematic drug use in the Netherlands than in most comparable Western countries. There is evidence that the legalization of medical cannabis in some states of the USA has been associated with a considerable reduction in fatal road traffic accidents, comparable with the benefits of laws requiring seatbelts. This, the authors of the study show, is mostly due to the large drop in the number of fatal crashes involving alcohol as people appear to substitute cannabis for drinking.

3.    Regulating access to drugs such as cannabis as in the Dutch model reduces the need for users to go to dealers. So it minimises their exposure to people whose main goal is to get their clients onto the most addictive substances such as heroin and crack. Indeed this was the main reason why the Dutch initiated the coffee shop model in the first place and it has been successful; by separating the markets of cannabis and heroin they have among the lowest rates of heroin use in young people in Europe. The Netherlands is now in the process of restricting tourists’ access, on a city by city basis, to coffeeshops, making them primarily for Dutch residents. As drug tourism was never the aim of the coffeeshop policy, this change is not without logic, however, given that there is already a mature market for cannabis that may now be pushed into the illicit market with a correlating effect on street disorder and crime, as has already been seen in Maastricht.

4.    Approaches to dealing with addicted users which swap punishment for healthcare have been successful. In 1994, despite strong resistance from the UN, Switzerland began a program which allowed long-term treatment-resistant addicts to take clean pharmaceutical heroin under medical supervision. This has been criticized for maintaining rather than ending addictions, but it has stabilised chaotic lives, allowing users to be socially reintegrated, getting homes and sometimes jobs, and as well as removing the health harms associated with polluted, inconsistent street drugs. Addicts in this treatment get fitter, they virtually never overdose, and very few die. Unlike those in other regimes, most stay in treatment, allowing some to progress later to abstinence. It isn’t just the addicts who benefit; crime fell enormously once users could access heroin from the State rather than profiteering dealers. The State, and taxpayers don’t lose out in this arrangement, the expensive program more than pays for itself in healthcare and law enforcement savings.

5.    Approaches which explicitly reject an evidence-based public health approach, but instead focus on incarceration and criminalisation of addicts, continue to utterly fail, at enormous financial and human cost. The Global Commission on Drugs Policy have just published a new evidence-rich report, well worth reading, which focuses on the effect of different approaches to drug users on the HIV/AIDS pandemic. The spread of disease cannot be considered a wholly natural, biological phenomenon, it is also social, economic and very political. Political choices determine whether a huge majority or a small minority of new HIV infections are caused by injecting drug use. In Russia, where organisations trying to help heroin addicts look after their health have been persecuted, a million people are HIV positive, over 80% of them through their drug habit. In comparison, here in the UK, Margaret Thatcher, the only PM we’ve had with a science degree, heeded her scientific advisors, brushed off moralising critics, and instituted a needle-exchange programme. Since then, UK policy has at least accepted the need for harm-reduction alongside punishment, and less than 2% of new HIV infections in 2010 were caused by injecting drugs. In the US, where incarceration rates are high, but harm-reduction measures (like distributing clean hypodermics) is politically taboo, unfunded or even illegal, HIV spreads in prisons where syringes carrying heroin and HIV are passed around. Whilst use of prescription heroin in a clean needle rarely harms anyone besides the user, these preventable HIV infections across the world in injecting drug users cause infections in their sexual partners and continually infuse HIV into wider society.

6.    Treating addicts with more humanity doesn’t make drug use look more appealing. The idea that less punitive approaches would encourage drug use is again a reasonable hypothesis, but science demands that hypotheses are tested against the evidence. The Swiss evidence shows that rather than making heroin more popular, numbers of people becoming addicts have steadily fallen. It has been suggested that whilst heroin use can appear rebellious where the focus is on punishment (think of Pete Doherty photographed with an entourage of police, or sashaying in and out of court), in Switzerland, young people think of addicts as simply ill, which deters use. It is no surprise that Switzerland’s policy has won broad democratic support and has inspired similarly successful projects in other European countries, including small trials here in the UK. It’s also no surprise that much of the world remains strongly opposed to this approach despite such strong evidence that it works.

Moreover criminalisation produces many perverse consequences that actually increase the harms of drugs and costs to society. Criminal networks coalesce around drug supply; America in the era of alcohol prohibition was the heyday of organised crime.  The lack of quality control in illegal drug markets leads to wholly unnecessary harms like deadly outbreaks of anthrax in heroin injectors. Dealers with concerns only for their profits adulterate and mis-describe drugs, for example selling the much more potent and riskier drug PMMA as the less risky ecstasy. Badly enacted prohibition also severely limits research so denies the possible therapeutic benefits of drugs such as MDMA for treating PTSD and psilocybin for treating depression and the anxiety of cancer.

It is now time to begin to introduce a more rational evidence-based approach to drug policy to minimise harms. We must consider all drugs, including alcohol, as part of the problem to be tackled. I hope that the Select Committee will recommend a more progressive approach than the current one of interdiction and punishment which has, and will continue to fail.


The BLF is an admirable charity that promotes lung health and supports those affected by lung disease. Unfortunately, last week they produced a press release promoting unfounded claims about the harms of cannabis to the lungs. These claims were uncritically parroted from this press release as ‘news’ by the BBC, Channel 4, Sky, the Independent, Telegraph, Metro, Evening Standard, the Huffington Post and more.

The BLF, who wish to promote awareness of “the serious, even fatal impact [cannabis] can have on the lungs”, managed to hit the headlines with a survey about public attitudes to cannabis commissioned alongside their new report reviewing existing evidence. Surveys, with their (often unsupported) appearance of objectivity, are a popular way for groups, commercial or otherwise, to win press attention. It has worked for them before – the Daily Mail has a ten-year old article archived online reporting a virtually identical story of BLF “research” apparently showing that the dangers of cannabis are underestimated, and worse than tobacco. Then, as now, the BLF received news coverage as if they had made a breakthrough just through publishing a survey and a report of evidence. Confusingly, whilst this is the BLF’s second special report on cannabis, they have never dedicated a special report to tobacco, which causes the vast majority of lung cancer deaths and many other lung conditions.

This time around, the BBC, whose science coverage usually deserves praise, rehashed the first lines of the BLF’s press release, writing “88% [of the public] incorrectly thought tobacco cigarettes were more harmful than cannabis ones – when the risk of lung cancer is actually 20 times higher”. In this sentence, as in almost every news article I have seen on the subject, almost 9 in 10 of the public are condescended to as being mistaken, but where is the evidence for this assertion that tobacco is so much kinder to the lungs than cannabis? Could the public perhaps be wiser about drug harms than the BLF and the media? I had a closer look at the BLF’s report to check their evidence.

The BLF’s report itself references a great deal of scientific evidence, but it seems to be an attempt to collect evidence that supports their predetermined opinion that cannabis harms the lungs, rather than exploring the evidence to find out what the balance of findings really suggests. When the evidence they found was mixed, they came to firm conclusions that the most alarming interpretation of the most alarming evidence was true. This is most striking in the case of the lung cancer claim that tops the press release, that a cannabis joint is 20 times as carcinogenic as a cigarette. This is an old chestnut, listed amongst Wikipedia’s list of popular drug myths. But that didn’t stop Kenneth Gibson of the Scottish National Party lodging a motion (look for S4M-03197) in the Scottish Parliament last week on 8th June endorsing the BLF’s claims and recommendations.

This claim about the 20-fold cancer risk is prominent in the introductory ‘background’ information section of the BLF’s report. Here it assures the reader that the evidence explored in the report (section 3.2) shows this. But the report contradicts itself: Section 3.2 on cancer actually very reasonably says that “studies in human populations have yielded conflicting evidence on the subject: some suggest there is a link between smoking cannabis and lung cancer while others don’t [3 references]. It’s worth noting that these studies are of limited value as they looked at relatively small numbers of people and didn’t take into consideration the quantity of cannabis smoked or the effects of smoking a mixture of tobacco and cannabis. In addition, some previous evidence suggests that THC may have anti-carcinogenic effects”.

Having explained, with directions to three references, that the evidence is mixed and inconclusive, the report’s writer(s) disappointingly then give a long and overgenerous account of one of the three papers referenced, a 2008 study by Aldington (a thorough scientific rebuttal of which can be found here). They then dubiously interpret the study as suggesting that a joint is as carcinogenic as 20 cigarettes. Christopher Snowdon has written a blog post on just why this interpretation is wrong. Do the BLF at least give other evidence an airing? After considering Aldington’s paper, a much smaller account is given of another of their references, which says cannabis increases lung cancer risk 2.4 times, and they do not write anything about their third reference, which found no link to lung cancer. This last study, by Hashibe et. al., looked at more people’s cannabis use over a longer time, and so has a claim to be the most valid. Why did the BLF reference three studies then largely ignore the findings of two?

We cannot doubt the BLF’s worthy intentions to help us all look after our lungs, and indeed there are harm-reduction messages that should be heard about cannabis smoke, specifically that if you must use the drug despite the risks, rolling with tobacco may increase risk of harms, and that using a cannabis vaporiser instead of smoking it may decrease harms.

The BLF’s lack of care with the evidence, and the media’s lack of care in fact-checking, could have the opposite effect from their good intentions. Public confidence in science as a means of getting to the truth can only be harmed when the BBC reports “experts” mistakenly declaring that what 88% of us apparently think about cannabis is wrong. What’s more, if the BLF’s misguided information is believed, people could actually be put at greater risk of lung cancer, for example by cutting down on the cannabis in their joints and padding them out with more tobacco, or by making parents relatively more relaxed about finding out that their teenagers smoking cigarettes every day than finding out that they smoke the occasional joint.

(Apologies for low res image).

What can be done? The ISCD contacted the BBC on the 6th of June, but as yet the BBC have not replied or removed the inaccuracies although they have now included an alternative opinion on the subject from Peter Reynolds of Clear. The Metro, on the other hand, can be thoroughly commended for their prompt and prominent publication of critical responses to their article from me and other readers. We will pursue further corrections, firstly by contacting editors directly, and if that fails, through the PCC. I will update readers of this blog on any progress.

The ISCD’s aim is for ordinary people, without scientific expertise, to be able to find reliable information about the effects and risks of drugs. With thousands of voices clamouring to be heard, each offering conflicting views, it’s a huge challenge. As I write, the BLF’s claim about cannabis cigarettes being more carcinogenic than tobacco ones has already found its way onto Wikipedia’s information about cannabis harms, so Wikipedia currently reports, on different pages, the same claim as an evidenced fact and as a popular myth. Though I trust it won’t be there long, this shows how easily misinformation can gain the stamp of truth. The ISCD website,, should help individuals who are looking for evidence-based information. Our drugs information page on cannabis provides scientifically evidenced information on the drug and its effects and harms. For information on the specific connection between cannabis and cancer, see Cancer Research UK’s balanced information.

We gave the BLF the opportunity to address the inaccuracies and inconsistencies of their report which they declined, thus missing an important opportunity to address the very real harms of smoking. Public health organisations are to be commended for trying to help the general public make better choices.  Unfortunately in this case, the choice made was to confuse rather than inform.