Cannabis and privileged access

July 27th, 2007 by Ben Goldacre in bad science | 50 Comments »

I’ve just been asked rather at the last minute to knock something out on cannabis and psychosis, and since I like to keep the news desk very happy these days, even though I have absolutely nothing interesting to say on the subject, I’m going to charge through reading the Lancet study over a sandwich: but one thing struck me as absurd. The media is full of people writing about this academic journal article, and yet I couldn’t get hold of it with my Athens login, because it’s not been published, so I had to pull in favours, and call around mates.

This means that the media – of all people – are a class privileged over academia, doctors and the public when it comes to access to the data; that for the whole of the media storm across Friday and Saturday, no interested academic, or member of the public, or blogger could participate, unless they were part of the chosen set, because they simply couldn’t see the paper.

This is utterly unacceptable to my mind.

Here is the paper.

Time and again we’ve covered the venality and incompetence of the media: and yet laughably the popular debate on this publicly funded academic work is conducted exclusively behind closed doors – by oldmedia employees – in a privileged world from which you, all doctors, and all academics are deliberately excluded.

Media embargoes should lift at the same time as formal publication, and not a moment earlier. The commercial commentariat have not earned their special status.


As of 1:45pm the Lancet cannabis paper, and indeed the rest of tomorrow’s edition of the Lancet, are suddenly magically available on their website.

I’m taking down my link as it is premium content, they charge $30 for you to read this work (funded by the Department of Health, for anyone who feels angry about this I recommend reading about the open access journal movement).

Interestingly the Guardian have now decided to post the paper for free for download here.,,2136062,00.html

I don’t know if they have a special arrangement with the Lancet where they pay the $30 per download for this premium content, or if they’re just trying to be punk like me?


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50 Responses

  1. wilsontown said,

    July 27, 2007 at 11:53 am

    Of course, any ‘interested member of the public’ would have trouble getting the paper without an athens password, even when it has been published…

    Point taken, though. How can you have a sensible debate about a paper when you can’t read it?

  2. Symball said,

    July 27, 2007 at 11:54 am

    Of course they don’t want you to see it before it has been reported. You might try and read it, even try criticising it before the media has had a chance to parrot the party line.

  3. Mushroom said,

    July 27, 2007 at 12:07 pm

    And there was me thinking it was something *I* was doing wrong.

    Thanks Ben

  4. Gimpy said,

    July 27, 2007 at 12:07 pm

    sorry i’m confused……are you saying that the media are discussing the paper without reading it or that they have been given access to it before publication?

    hungover……..brain slow today

  5. woodchopper said,

    July 27, 2007 at 12:08 pm

    Best way to get something in the news is to offer a few journos ‘exclusive’ access.

  6. Gimpy said,

    July 27, 2007 at 12:21 pm

    8. that’s appalling. I am consumed by righteous indignation.

  7. elfy said,

    July 27, 2007 at 12:34 pm

    There was an article on the Language Log about precisely this situation a few days ago: Apparently it’s pretty common for PNAS to give out studies in advance with an embargo that expires a few days before the study is actually published.

  8. rambaut said,

    July 27, 2007 at 12:35 pm

    From personal experience, what happens is that the journalists are allowed to share the paper with academics in order to get comments (this is before the embargo is lifted). But of course the journalist is in a hurry to get their piece ready in time for the embargo date so they give you no time to read and understand the paper.

  9. elfy said,

    July 27, 2007 at 12:42 pm

    prosthesis: oh, yes, I’m sure all the major journals do release them under embargo. I don’t think that many of them will regularly release them under an embargo that expires before the study is actually published, though. Most newspaper stories on unpublished studies in the UK seem to come directly from the researchers, as far as I can tell.

  10. Azimov said,

    July 27, 2007 at 12:49 pm

    Surely cannabis can’t directly cause psychosis anyway, psychosis is a symptom of the much larger and broader condition schizophrenia. I’m probably wrong, having absolutely no knowledge in the area of psychiatry.

  11. Zamzara said,

    July 27, 2007 at 12:59 pm

    First paragraph in the report: “there is a dose response effect”, yet the first thing they said on BBC Radio 4 news was “a new study shows that smoking even a single joint could cause a 40% increase….”

    It would be funny, if only people didn’t take these news reports as scientific fact.

  12. superburger said,

    July 27, 2007 at 1:03 pm

    btw i tried to include the html tag

  13. superburger said,

    July 27, 2007 at 1:03 pm

    devils advocate. jesus, i won’t bother next time.

  14. amoebic vodka said,

    July 27, 2007 at 1:24 pm

    Unless I’m totally misunderstanding Ben, his point was that no-one could access it at all, even with a subscription to the journal.

    “The media is full of people writing about this academic journal article, and yet I couldn’t get hold of it with my Athens login, because it’s not been published, so I had to pull in favours, and call around mates.”

    I’m not sure he necessarily had an issue with the press getting access to it before anyone else, just the press being able to comment publicly on it before anyone could see the original paper. I always thought they got the press release and not a copy of the paper itself, though.

    As an aside some ex-science correspondent was moaning about the embargo system in the Indie a week or so ago. Apparently the reason for the Observer’s MMR scaremongering was all the scientific community’s fault for wanting to put their data in a peer reviewed journal rather than going directly to the media.

  15. prosthesis said,

    July 27, 2007 at 1:26 pm

    i see the guardian are now linking the pdf of their front page…anything to do with this?

  16. icarusfall said,

    July 27, 2007 at 1:28 pm

    Actually, I thought the coverage on Radio 4 this morning was very good. They went through what they did (“we examined all the different studies in this area”). They explained that the incidence of psychosis was very low, and so the increase only seems large in comparison. The academic they interviewed was very good, and I don’t think their summarising was particularly hysterical. They pointed out that the headline figure is an average over all rates of intake, so you can’t say “one joint sends you mad”, but that it does seem that there is evidence for a link between psychosis and cannabis intake.

    That’s OK, isn’t it? It’s a paper published in a proper journal, and the researchers themselves were interviewed about it. Ticks all of Ben’s boxes, I reckon.

  17. superburger said,

    July 27, 2007 at 1:32 pm

    again, as devil’s advocate, how is it any different to ‘advance screenings’ of movies?

    in many ways a ‘big’ paper in the major journals is the science equivalent of a summer movie.

    you know it’s coming, heard the basic plot in the pub, the media have an opinion, but you wait till you see it yourself to form an opinion.

  18. superburger said,

    July 27, 2007 at 1:46 pm

    if only Dr Zammit’s name was Dr Zammo…

  19. prosthesis said,

    July 27, 2007 at 1:58 pm

    they’re not embargoed, you just have to pay for access to them. there’s a difference.

  20. maninalift said,

    July 27, 2007 at 2:06 pm

    Theoretical physicists and mathematicians publish almost everything in the form of preprints on arXiv. This means that ideas are shared rapidly, no waiting 6 months or more to get published and in some cases material is published in a speculative or unpolished form.

    Of course there is a big incentive: As a theoretician you want to lay claim to an idea first as your work will be rendered unpublishable if someone else publishes the same result. Therefore the ability to immediately share a publication with the whole scientific community is very valuable.

  21. superburger said,

    July 27, 2007 at 2:10 pm

    “As a theoretician you want to lay claim to an idea first as your work will be rendered unpublishable if someone else publishes the same result.”

    surely if you are onto a winning idea you can publsih the outline as a letter or communication, then the finished article as a full paper?

    it has always puzzled me that physics and maths for got preprints while chemistry (and biology?) don’t. Is the pace of physics that much faster, or is it a culture thing?

  22. Gimpy said,

    July 27, 2007 at 2:18 pm

    gah didn’t read bens update

  23. maninalift said,

    July 27, 2007 at 2:22 pm

    “surely if you are onto a winning idea you can publsih the outline as a letter or communication, then the finished article as a full paper?”

    Why would you want to when you can publish it immediately on a searchable database that everyone in your field will refer to? I even have arXiv on RSS (via the lovely Google Reader) so I see everything submitted in my area the very same day.

  24. superburger said,

    July 27, 2007 at 2:30 pm


    i can see the advantage of arXiv – i know how much physics, astronomy and maths use it, it’s just odd that other sciences don’t go for it in the same way.

    What do the physics journals think of it?

    i mean will Science or Phys Rev Let publish something that has been seen on arXiv?

    i’m not knocking it, i’m just curious.

  25. maninalift said,

    July 27, 2007 at 2:42 pm

    And also the existence of the journals is still important for the peer review it provides (in that sense arXiv is parasitic). Perhaps the journals are largely paid for by academic institutions which need to supply complete access to the definitive final peer-reviewed publications.

  26. Oldfart said,

    July 27, 2007 at 2:47 pm

    I don’t like cannabis and never have. It always made me feel like I was suffocating and made my teeth hurt. Even so, all the wailing and whining that will result from this report, all the extra felons that will be produced far exceed the damage done by the drug itself. It will be especially hypocritical (the public response) when one considers that alcohol is still legal and will continue to be legal and is far more dangerous. Especially so in the USA where the right wing moralists will say “I told you so!” as they continue to puff and drink away at home in their closets.

  27. superburger said,

    July 27, 2007 at 3:06 pm

    if smoking cannabis gives you schizophrenia, then the best thing to do is criminalise people with mental illness, ‘cos the prison system is the best place for people who have mental health problems.

    Plus having a criminal record coupled with a history of schizophrenia is an sure-fire way to lead a happy, stable, productive life.

    or am i missing something?

  28. Wonko said,

    July 27, 2007 at 3:10 pm

    Spot on Ben. Some of us have to respond to media stories of this kind, and need to see the paper, not just a journalist’s version of it.

    This is not simply a matter of academic debate. Highlighting this issue with this paper is very clever because of the huge moral panic around cannabis. One possible outcome of a lack of access to the paper is that by the time detractors get to access and challenge the data, the media will have established the “cannabis causes psychosis” story in the public mind.

    Remember that the outcome of the current moral panic could be to see large numbers of people criminalised, placed on government registers, and banned from getting employment in education and public services. When the stakes are so high, it is essential that the science is fully accessible in the public domain.

  29. gus said,

    July 27, 2007 at 3:35 pm

    with regards to open access etc. I think that a bigger problem is the rise of journals for which you have to pay to actually publish in. I looked at few journals recently that quoted US$500 to publish your work. I my mind this starts to raise all sorts of questions, in a few years time will publishing have to be built into any grant proposal? will there be a sliding scale for publishing research? how will it operate? (rated according to impact factor?). This will have unreasonable impacts on those who cannot afford to publish work, such as PhD students and those from developing countries. It could get to the situation where the ability to pay is almost as important as the quality of the research. It would also make it harder to access the latest research as it remains unpublished or in obscure, hard to locate journals. Will there come a time when you here the phrase “i’m sorry we can’t afford to publish in nature, it’ll have to be the orkney pig breeders gazette”

  30. wilsontown said,

    July 27, 2007 at 3:36 pm

    I had a go at posting a comment under the Daily Mail story. Their headline is “Smoking just one cannabis joint raises danger of mental illness by 40%”, which is flat out wrong, as a cursory glance at the paper would tell you.

    Oddly enough, they haven’t actually printed the comment…

  31. wewillfixit said,

    July 27, 2007 at 4:06 pm

    Just to put it into perspective – if the prevalence of schizophrenia is 1%, a 40% increase will only increase your risk to 1.4%. So your absolute risk is still pretty small.

  32. gus said,

    July 27, 2007 at 4:10 pm

    an extreme example I know, but as more and more journals start charging for publishing surely freemarket economics (?) dictate that the “better” (ones with higher impact factors) journals will charge more, I realise this will probably not happen with the likes of nature and science, but it seems a distinct possiblity for middle and low ranking journals

  33. superburger said,

    July 27, 2007 at 4:14 pm

    but publishing isn’t a perfect market.

    there is a need for people with lower-interest research (3rd world countries) to publish their work, and that’s why so many of the smaller journals still exist. They have to charge to cover their costs, as they can’t sell as many subscriptions or advertising.

    Bigger journals sell lots of subs, so don’t always need to make page charges.

  34. deadmanjones said,

    July 27, 2007 at 4:25 pm

    As others here have pointed out, this 40% figure is basically derived from:

    1 out of a 100 people suffer schizophrenia.
    1.4 out of 100 cannabis users suffer schizophrenia.
    That is 0.4% more.
    0.4% is 40% of 1%.

    Daily Mail notwithstanding, I would dearly love to bash the BBC, Guardian et al for using “40% higher risk” in their headlines rather than “0.4% more cases”, but sadly it is the Lancet that is headlining this figure. There is nowhere that science can be presented any more where it will not be spun, bitesized or headlined.

    Even ignoring how appropriate the 40% figure is, the increased “risk” has 3 possible explanations that I can see, and only the first is being emphasized.

    1. General increased risk to cannabis users
    2. Increased risk to those already at risk of schizophrenia, or
    3. Schizophrenics are more likely to have a toot on the old wacky backy.

    I’d go for option 3, but what I do I know. I’m neither a scizophrenic nor a cannabis smoker.

  35. gus said,

    July 27, 2007 at 4:34 pm

    It isn’t necessarily smaller journals (depending on your definition of smaller) that are starting to do this, it’s the middle ranking ones. As you stated before, the likes of Nature/science etc. won’t have to worry about money due subs and online advertising. Similarly the smaller journals are unlikely to bring in charges initially, because how many people would pay to publish in a journal with a small readership and a low impact factor. It’s the mid ranking journals (and US ones in particular) which are starting to charge, and these are the ones which many people tend to aim their work at in order to establish a reputation

  36. barnics said,

    July 27, 2007 at 4:38 pm

    I notice the Daily Mail had a link beside their story explaining how extra terrestrials are among us. Or at least flying around over England.

  37. Nanobot said,

    July 27, 2007 at 5:14 pm

    I think perhaps scientists should hold their tongues and their pre-prints until the work has undergone peer-review myself.

    re: Physics/Chemistry publication cultures. As a chemist in a physics department I’ve had the opportunity to experience both cultures of publication and there really are equally good arguments for both, so I think it is just down to consensus and tradition.

  38. prosthesis said,

    July 27, 2007 at 5:22 pm


    i believe they controlled for your option 3, or ‘reverse causation’ in the analysis, so it is much more likely to be a combination of 1 and 2.

    i’m no expert on meta-analysis, so i’m happy to be corrected, but i think the relative risk of 1.4 seems fairly generated from the data they have, and they are very cautious in their conclusions. which obviously results in “1 spliff and you’re mad” if you write for the mail.

  39. ceec said,

    July 27, 2007 at 6:51 pm

    Just skimmed the paper. The authors are quite careful to point out that causation is very difficult to establish using these data, although they still go on basically to say that the link is causal i.e. that cannabis causes psychosis.

    Given that cannabis is commonly available and used, it is certainly also possible that people feeling psychotic (perhaps for the first time, as teenagers when they are also trying cannabis out for size) might use it to feel better (and it might work), or that it eventually makes their symptoms worse, or both.

    Nothing in the paper, unfortunately, can answer the fundamental question about causality (as they point out – this would be very difficult). Knowing you have the relevant symptoms and reporting them might come later than their actual onset, for instance, which makes it hard to assess whether or not cannabis comes first. Dose-response is a bit of a red-herring as well for the same reason(i.e. worse psychosis might make you want to smoke more dope).

    This obviously doesn’t mean that their conclusions are wrong – just that they might be.

    A small technical point re. the 1.4 estimate: meta-analyses are often a bit dodgy (adding apples to oranges etc.). You use I2 (measure of heterogeneity) to measure the extent to which your estimates are measuring the same thing. Low I2 is good. Some of the pooled estimates in this paper have very high I2 (>50% is considered in some quarters to render pooled results meaningless). Haven’t had time to read the paper carefully enough to see if the 1.4 increased odds comes from from pooled figures with high I2 or not. Hope not, but it might be worth checking.

  40. Quixotematic said,

    July 27, 2007 at 7:30 pm

    I was reading in the Independent that the point has been raised since publication that there has been no overall increase in the rate of schizophrenia diagnoses in the UK over the past 40 years.

    It seems then, that the only increase has been in the number of diagnoses implicating cannabis as a causal factor. This suggests that we may be witnessing merely a diagnostic fashion trend, to which medicine is no less prone than any other field of human endeavour.

    I would very much like to see a comparison with the risks intrinsic to other, unpersecuted pursuits, like leisure motorcycling or mountaineering or eating sashimi.

  41. RS said,

    July 27, 2007 at 8:01 pm

    ‘now’, not ‘no’

  42. Andrew Clegg said,

    July 27, 2007 at 10:59 pm

    3 thoughts.

    – 800 more psycho cases [(c) 2007 Alasdair Philips] per year. Oh noes!!1!!1! Well it’s hardly an epidemic is it. Especially combined with:

    – That claim in the Indie and elsewhere about incidence of schizophrenia actually staying flat. [Are schizophrenia and psychosis medically the same thing? If not then someone’s talking at cross purposes.]

    – Also: paranoia being closely associated with schizophrenia and psychosis, I can’t help wondering if knowing that the blue meanies could lock you up for enjoying a smoke might be a contributory factor in borderline cases.


    PS superburger (50) — OA journals don’t charge if you’re from a third world country. Are there non-OA journals where you pay to publish? What fool would do that?

  43. mattieb said,

    July 28, 2007 at 2:17 am

    Presumably massive medical research programmes are going to be significantly less easy to replicate (and test) than a theoretical physics paper… Therefore the issue of peer-review (or, the lack of it on arXiv) becomes slightly less relevant. (I’m doing theoretical physics, and if there’s a useful equation in an preprint, I can probably work out for myself if it’s correct or justified!) also contains a lot more than just preprints; whole books, and irrelevant (but interesting) v.v.v.niche stuff that no journal would ever want to bother with.

  44. Suw said,

    July 28, 2007 at 5:57 pm

    To respond to Superburger’s devil’s advocate questions, I’d say there’s a significant difference between giving the press pre-screening of films or review copies of books. In both of those cases, the public realises that the journalists are merely giving an opinion as to how good the film/book is, and they are likely to make their own mind up once they see the film or read the book.

    How many Daily Mail, or even Guardian readers are going to go and read this paper, even if it’s freely available, in order to make their own mind up? I would posit that an insignificant number will pursue the matter any further than reading the pieces published in the papers, or watching the news.

    Thus any interpretation that journalists make embeds itself in the public’s mind as “true”, and is never challenged by the original paper itself.

    Equally, if other scientists cannot read the paper before the media publish their opinions, then they can’t respond in a timely manner. Nor can other journalists who weren’t privy to the early release write anything that may offer a different view of the paper

    Generally, I hate embargoes and exclusives, and not just for scientific papers either. I think it encourages lazy and irresponsible journalism – if you’ve been given an ‘exclusive’, are you really going to do a rigorous fact check? Are you going to quote contradictory evidence or opinion? Methinks, probably not.

  45. prometheus said,

    July 28, 2007 at 8:37 pm

    This phenomenon (of results being trumpeted all over the place by the media before the relevant paper has even been published) goes on all the time. A recent example was propagated by the IPPR, whose doom-ridden report on British children (not the one released this week, another several months ago)caused a media feeding frenzy. As a researcher and a parent, I wanted to find out what all the fuss was about, and scrutinise the data, methodology etc in more depth. However, when I went to the IPPR’s webesite to view the report, I found that it had not yet been published. When it was published, it was not cheap (from memory, £15-30). I find it deeply disquieting that reports like this which seem likely to have a lasting influence on future policy regarding children are uncritically blasted everywhere without even one shred of critical scrutiny, and even when they are published, they are not subject to peer review.

  46. jodyaberdein said,

    July 28, 2007 at 10:02 pm

    ‘publishing isn’t a perfect market’

    Clearly the market has resulted in such an even distribution of wealth elsewhere it would be the perfect model to apply to scientific knowledge.

    In my copy of ‘Reliable Knowledge’ John Ziman proposes that the goal of science ‘is a consensus of rational opinion over the widest possible field’, p3 L4. Furthermore ‘imperfections of communication or of critical analysis reduce the reliability of science in every field’, p4 L 29

    I could go on quoting but to my mind science consists only of the messages communicated and recorded between scientists. It is the scientific archive that is key, and by implication access to it.

    I strongly feel that many of the woes so often expressed here regarding popular scientific illiteracy would be consigned to history if only we got ourselves out of those ivory towers and opened the libraries to all comers.

    This may also result in an significant improvement in the quality and relevence of the messages we store in the archives. No more me-too drugs on the front page, or indeed hundred thousand dollar a year treatments in a world where in the last thirty years we’ve invented under a score of new tropical medicines.

  47. Don Cox said,

    July 29, 2007 at 5:37 pm

    “but sadly it is the Lancet that is headlining this figure.”

    The Lancet is not a serious scientific journal. It is a newspaper for doctors.

    It was the Lancet that started the MMR scare, and the Lancet that published the wild estimates of “excess deaths” in Iraq. I wouldn’t believe anything I read in it, any more than the Daily Mail.

  48. ceec said,

    July 31, 2007 at 8:43 am

    Don cox (above now 54) I assume you are joking re. Lancet, but just in case: Excess deaths in Iraq – I read that paper and can’t fault the methods. Why do you think the estimates were “wild”?

  49. terryhamblin said,

    July 31, 2007 at 4:49 pm

    Several points have been raised but some are invalid and many sem confused.
    1] The Lancet is a serious journal, but it among the serious articles (like the one last week reporting the CLL4 trial in chronic lymphocytic leukaemia) they splash headline-grabbing ones like the deaths in Iraq, MMR and the Cannabis and schizophrenia articles. 2] Richard Horton, the editor, sees himself following in the radical footsteps of Thomas Wackley, the founder of the journal. 3] The Lancet is taken by virtually all medical libraries, so no serious academic can complain about not having access. It is actually taken by many public libraries, so members of the general public can often read it. 4]Finally, on access, a personal subscription is cheaper than an annual subscription to the Guardian.
    5] It costs nothing to publish in The Lancet, unlike the Open Access Journals and many Society Journals. Some academics do include publishing costs in their research grants, but I’m not sure that this is a reasonable cost to inflict on charities who fund much medical research, not is the average doctor working in the NHS subsidised in this way.
    6]Psychosis is not exactly the same as schizophrenia. Depression can also be psychotic. 7] If you have lived with someone schizophrenia you certainly wouldn’t want to encourage anyone else to have it. Even if there is a 40% increase of a vey small number you would still want to avoid it. 8] Association doesn’t imply causation. Apart from the possible conclusions that a)Cannabis makes you mad and b) you have to be mad to smoke Cannabis, there is also the possibility that cannabis smokers and schizophrenics are linked in some other way. even if all the confounders they can think of have been excluded. 9] Ben’s original point that the media should not have access before the profesionals is absolutely valid. GPs have been complaining for years about patients bringing in their copy of the Daily Mail to demand a new treatment before they have even read their BMJs.

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