Cannabis - sorry about the apology

The Independent on Sunday reached a new peak of absurdity last weekend when it blazed over its front page: Cannabis - an apology and reversed its 1997 campaign for legalisation of the dope, apologising to its readers for leading them astray. The Indy frets that:

Record numbers of teenagers are requiring drug treatment as a result of smoking skunk, the highly potent cannabis strain that is 25 times stronger than resin sold a decade ago. More than 22,000 people were treated last year for cannabis addiction - and almost half of those affected were under 18.

It feels like a modern day Reefer Madness (view classic 1937 film) with 'skunk' playing the role of the evil marijuana. One struggles to know where to start with dismantling this rubbish! But lets try...
25 times?
1. Today's Guardian 'Bad Science' column Cherry picking data to make a point about cannabis deals with the 25x thing very convincingly - there has always been a large range of potencies in cannabis leaves - but averages hover in the 4-12% range for the active ingredient THC. The Indy's scare is an exaggeration, but it doesn't matter anyway, because....

Whiskey 10 times as potent as beer
2. ... even this misses the point. Users control their intake ('titrate' in the jargon) to achieve a desired dose. The most obvious example is alcohol - where people drink pints of weak lager or sip at a small glass of whiskey. There is no moral panic about single malts because they are 10 times stronger in alcohol than Fosters. Similar effects apply with 'light' cigarettes - one reason why these are a con is that they are smoked differently so the user gets the same dose of nicotine, the active drug and all the poisonous tars and gases that come with it [see Why low-tar cigarettes don't work]. Drugscope points out [here] that the main risk is that: Skunk's strength and speed can sometimes catch out inexperienced users. Like taking a swig from a pint pot only to find it is full of scotch.

Thousands in treatment?
3. According to the Indy, "the number of young people in treatment almost doubled from about 5,000 in 2005 to 9,600 in 2006, and that 13,000 adults also needed treatment". Well the number of persons undergoing treatment is at least as likely to reflect changes in treatment practice - for years treatment services have been stretched dealing with epidemics of crack and heroin addiction. Note that 22,600 people in treatment is less than 1 in 1,000 of the 2,775,000 16-59 year olds that had used cannabis in the past year [Home Office statistical Bulletin 15/06 table 2.1 p11]

Cannabis epidemic?
4. In fact, the Home Office survey shows that the number of cannabis use in the last year among 16-24 year olds has fallen by 24% since 1998 from 28.2% to 21.4% in 2005-6 [Statistical Bulletin 15/06 table A2.1 p45] - with the sharp falls in 2004-5 and 2005-6, the years follow the reclassification of cannabis from class B to the less serious class C - see chart above. Mind you, class A use, mainly cocaine, has gone up.

Cannabis more harmful than LSD or ecstasy?
5. Particularly mendacious was the Indy's spin on a paper to be published later that week in the Lancet [Development of a rational scale to assess the harm of drugs of potential misuse], about which the Indy claimed: "New research being published in this week's Lancet will show how cannabis is more dangerous than LSD and ecstasy." The paper did indeed show this, but for most of the commentary the shock news was that LSD and ecstasy, both class A drugs, were less hazardous than legal drugs alcohol and tobacco [BBC]. The chart from the Lancet study (below) shows the ranking by harm of the various drugs, and colour codes their legal classification - click to enlarge. And yes, this rates cannabis less harmful than alcohol or tobacco.



Save lives by making it illegal?
7. But even all of this misses the point. There is no doubt that cannabis is risky and can be harmful to some users [see literature], and and probably linked to serious illnesses like schizophrenia. But who said that making something illegal because it is dangerous is the best way of dealing with the public health problem? There is a leap of induction in the argument that making things illegal somehow makes them go away. The criminal justice system isn't an obvious way to deal with a public health problem. Maybe legal supply would have some advantages: proper warnings, clear indications of dosage, no contamination, less contact with dodgy dealers, regulation by law rather than violence etc. The most credible and independent drugs charity, Transform, has made a great case for legalisation on multiple grounds - read: After the war on drugs: options for control. In 2001, in a superbly argued survey of illegal drugs, The Economist drew on its liberal instincts and called for legalisation of all drugs - see Stumbling in the Dark / Set if Free:

"the case for legalisation is difficult, the case against is worse"

Back in 2001 when I was working in tobacco and public health, I surprised many colleagues by calling for legalisation of cannabis. Here is the case made at the time: Legalising cannabis - discussion document. (It doesn't necessarily reflect the views of the organisation now!).