The publication last week of a substantial meta-analysis of the link between cannabis and psychosis has brought about some significant debate both in the maintsream media and the AOD profession.

The Lancet podcast interviews one of the article’s authors and he’s very up front about the fact that establishing causality from a meta-analysis is fraught with difficulty. That said, the paper’s authors believe around 50% of cannabis-related psychosis is probably related to other factors like use of other substances, pre-existing mental illness and so on. That still leaves 50% of cases where there may be a direct causal link. The authors go to great lengths to emphasise that the link cold be explained by another factor, but that given there’s not likely to be significant new findings in the near future, the current practice of advising that cannabis use canbring a risk of psychosis is an appropriate strategy.

Dr Malcolm Dobbs from the Victorian Department of Health and Human Services summarised the issue perfectly:

“We don’t have perfect evidence about whether there is a causal relationship between cannabis use and increased risk of psychosis, but this meta-analysis has confined its choice of studies to longitudinal cohorts, and made allowances for possible factors that could explain (confound) differences in risks between cannabis users and non-users.

The authors of the comment estimate that if there is a true causal relation, the increased risk would mean that 800 yearly cases of schizophrenia in the UK could be prevented through cessation of cannabis consumption.”

Of course, whether a direct causal link is established or not, the pivotal issue is effective education programs and not falling into the trap of demonising a substance that has some demonstrably beneficial medical effects in the right circumstance. Any illicit substance is great fodder for misrepresentative sensationalism. The meta-analysis is purely another small step toward understanding the link between cannabis and mental health – there’s still plenty of work to be done yet.

A general update to MSIC supporters has been distributed by Medical Director Ingrid Van Beek. It makes an interesting read overall however the marked criticisms of the “pseudo-science” of the NGO Drug Free Australia (DFA) are noteworthy.

The full missive:

“Dear Supporters

On behalf of the staff of the MSIC, I am pleased to inform you that legislation to extend the trial of the Medically Supervised Injecting Centre (MSIC) for a further 4 years (to the end of October 2011) has now passed successfully through both houses in NSW Parliament. We are of course glad that the NSW Government continues to support this important public health initiative. The support for this bill from the Greens, Independents including Clover Moore, Dawn Fardell and Robert Oakeshott and five Liberal MPs (who were allowed a conscience vote) was also very encouraging.

While the parliamentary speeches in favour of the bill were heartening for the staff at the MSIC, comments like the following made by the member for Castle Hill in his speech against the bill were less so: I am willing to bet that some of those working at the centre will be trawling the streets for addicts to get their numbers up because, after all, it is their livelihood. Indeed, when I pointed out the escape clause [the new provision that a review will be triggered should MSIC utilisation drop below 75% of current levels] to my wife she immediately suggested that staff would pull people in off the street and get them to inject inside the injecting room so that they could maintain their jobs.

Likewise, repeated assertions that the MSIC merely encourages experimentation with dangerous drug cocktails were abhorrent to us. I sometimes wonder if anyone ever suggests of my cardiologist colleagues that they must be very concerned about the impact of the decreasing rate of tobacco use in the community on their “livelihoods”…surely not, given their obvious life-long career commitment to improving the community’s health status. Similarly those of us who have chosen to work with drug users in what is arguably one of the most challenging fields within the public health sector don’t deserve to have such aspersions cast.

It was also deeply disturbing to see the extent to which the misinformation produced by Gary Christian of Drug Free Australia (DFA) permeated many of the speeches of those opposed. That this compilation of pseudo-science gained credence comparable to the various reports tabled by the team of internationally recognised researchers from Australia’s National Centre in HIV Epidemiology and Clinical Research who undertook the MSIC’s evaluation, is a travesty. I suspect that many of the MPs who used DFA’s various statistical extrapolations in their speeches didn’t even realise that apart from being fundamentally flawed, they referred to the first 18-month period of what has now been a 6-year trial. But I am reassured that it did little to change the way the politicians actually voted in the end.

I have pasted hereunder the MSIC’s response to the 6 key arguments circulated by Mr Christian to all MPs prior to the parliamentary debate for your information (attached herewith).

Finally, to coin the words of DFA’s CEO: that the Australian Medical Association, the Royal Australasian Colleges of Physicians, Emergency Medicine, Psychiatry, the Alcohol and other Drugs Council of Australia, the Australian Drug Foundation, the Australasian Society of HIV Medicine, the Hepatitis C Council of NSW, the NSW Users and AIDS Association, the AIDS Council of NSW, Family Drug Support, the Ted Noffs Foundation, Reverend Bill Crews of the Exodus Foundation, Sydney City Council, all of the parishes in Kings Cross, the large majority of local residents and businesses in Kings Cross and many others support the MSIC – speaks for itself.

Your ongoing support is greatly appreciated. Thank you.
Dr Ingrid van Beek
Medical Director”

If you look to the left of this post you’ll see we are now featuring the latest news on AOD from around the world. If you know of a site that we shold add to the list please don’t hesitate to let us know.

Enjoy!