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Sunday 17th June 2012

The Cuban Missile Crisis took place just after the start of my second year in high school. I remember it because our English teacher, a former British ambassador to Russia, decided to get us to debate the issues. That meant having someone speak from either side of the situation and I was chosen to present the case for Russia’s deployment of missiles close to the USA and argue that the USA should stop its interference in the affairs of an independent country, Cuba.

It was very interesting trying to find points to present that went against my inclination to think that the USSR was very much at fault and that all of the right lay with the USA.

I don’t know how much of a legacy of disinterested assessment I retain from that day in school but I thought I’d try and apply any there is to a new publication about the effect of Cannabis sativa, marijuana, in patients with mental health problems.¹

In order to make sure I was working from the full primary source I swallowed hard and paid out my $37.49 to be able to download a pdf of the document. I should like to assure The International Task Force on Strategic Drug Policy (ITFSDP) that this money came out of my pocket and not from any of the ‘Various well-funded pressure groups’ it believes are the only people interested in reform.

TThere has not, so far, been a great deal of reporting about this paper, perhaps, because it is still at the ‘final proof’ stage and has not yet appeared in the hard copy journal but ‘medwirenews’ headlined its story ‘Cannabis use linked to reduced mortality in psychosis’.²

When it does appear in the journal, there may be a greater response and the headlines in the mainstream media are likely to be more sensationalist than a medical news website so I couldn’t help wondering what anti-cannabis individuals will make of it.

I tried to look at the paper from the point of view of Kathy Gyngell or Mary Brett or even Prof Les Iversen. I thought about adding another name to that list but decided that inside the mind of Peter Hitchens is one place I really wouldn’t want to be.

The link below1 will take you to the abstract but, in 25 words, the paper found that people with psychotic disorders who had been lifetime users of Cannabis sativa, marijuana, were less likely to die than those who did not use cannabis.

Actually before adopting a prohibitionist persona, I should say that the authors are very clear that there is a need for larger epidemiological studies to replicate their results before this unexpected outcome can be confirmed.

When I think about it, with my prohibitionist cloak on, I would, probably, play up that same point. This is only one study and its results cannot be relied upon unless other studies confirm them. True, I’d have to hope that no-one would point out all the times I’d relied on a single study if it happened to report something that suited my position.

I could try attacking the selection of subjects. The authors had access to the medical records of 4,434 people, from which they identified 1,222 meeting the criteria for schizophrenia, schizoaffective disorder or psychosis not otherwise specified (NOS) and were 18-55 years of age but only focussed on the 762 for whom there was information on lifetime substance use. I might try and argue that the chances are that most of the 460 people excluded were non-users because, had they been users, this would have appeared in their records. However, if the 460 unknowns are added to the 467 and the assumption, certainly erroneous, is made that none of the 460 died in the follow-up period the mortality rate for non-users at 5.3% is still higher than the 4.4% for users.

The authors took substance users to be those using regularly or frequently and treated those who used substances occasionally, lightly or infrequently as ‘non-users’. The authors don’t seem to have given a clear definition of how they applied these criteria so I may be able to challenge the notion that ‘non-users’ are. I might try and argue that the possibility that light or occasional use leads to increased mortality has not been explored but the problem there is that I’d have to argue that this would mean you are better off being a regular user than only using marijuana infrequently. ‘Gyngell says smoke lots of cannabis’ is not a headline I expect to see.

Overall, I’m struggling to find any blatant flaws in this paper but I’d be interested to hear if I missed any. Prohibitionist me might decide it is better to ignore it and pretend it didn’t happen.

Stepping out of that strange place that was my attempt to create the combined mind of Gyngell, Brett and Iversen, I did find one disappointing comment. In their lengthy section on ‘Strengths and Limitations’ they cite the COMT gene paper from 2005 that, as I noted before, Wednesday 9th November has not only not been replicated but, in fact, the latest work on the subject, last September³, found ‘There was no evidence of an interaction…between cannabis use and COMT’.

Overall, then, this study seems to have done a pretty good job of avoiding flaws in reaching its conclusion but, just to give a reminder to any reformists who might be tempted to misappropriate this research, that conclusion was that larger studies should be done to see if this result is replicated.

References

^1.Alcohol and cannabis use and mortality in people with schizophrenia and related psychotic disorders  Journal of Psychiatric Research 16th May 2012
^2.Cannabis use linked to reduced mortality in psychosis medwirenews 22nd May 2012
^3.Cannabis, COMT and psychotic experiences The British Journal of Psychiatry 22nd September 2011

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