Saturday, June 25, 2011

"splendidly apposite" comments on cannabis, from Paul Flynn MP's blog

Reefer madness

...from the blog of Paul Flynn MP:

An otherwise respected MP Charles Walker disgracefully added to the hysteria of unscientific claims on links between cannabis and mental ill health.

A clutch of splendid comments has been made on ‘They work for you’ site to the answer I had when I asked the Government for their view.  Minister Ann Milton was guarded:

“In some people, however, intoxication leads to attacks of paranoia and confused feelings...the prevalence of these acute psychological reactions to cannabis is uncertain’.

In relation to long-term psychotic illness, the report states that:

‘On balance the council considers that the evidence points to a probable but weak causal link between psychotic illness and cannabis use. Whether such a casual link will become stronger with the wider use of higher potency cannabis products remain uncertain’.

Angus N had added his comments to the site, which are splendidly apposite.

"Glyn Lewis, Professor of Psychiatric Epidemiology at the University of Bristol, one of the world's leading experts on this subject, went on record recently to say that "...there is no certainty of a causal relationship between cannabis use and psychosis".

It is very welcome to see that this is also the line Anne Milton is taking, in keeping with the findings of the ACMD.

As regards the recent increases in the potency of UK cannabis and the fear of a consequent increase in long-term psychotic illness, there are accurate figures available that show from around 1995 - 2005 the strength of typical UK cannabis roughly doubled, and the typical levels of CBD, an anti-psychotic, dramatically declined.

"Potency of D9-THC and Other Cannabinoids in Cannabis in England in 2005: Implications for Psychoactivity and Pharmacology" by Potter, Clark and Brown shows that from 1995 to 2005 typical cannabis potency in the UK roughly doubled to around 13.9%THC.

Potter's team then voiced the widespread concern that a possible psychosis epidemic may be on the cards in the UK due to the rise of the new intensively bred "skunk" strains of cannabis, which were eclipsing traditional imported Moroccan hashish.

A similar rationale was made by Robin Murray to back a change of editorial stance at The Independent in March 2007, as championed with famously inaccurate statistics on potency by Rosie "30 times" Boycott and John "25 times" Rentoul. Ironically, this development of the cannabis market appears to have been driven by the very prohibition-based drug control policy that The Independent changed its editorial stance to back.

Fortunately the same period of 1996 - 2005 was also covered in a study the ACMD commissioned: "Assessing the impact of cannabis use on trends in diagnosed schizophrenia in the United Kingdom from 1996 to 2005" by the Department of Medicines Management, Keele University.
The Keel University study "did not find any evidence of increasing schizophrenia or psychoses in the general population from 1996 to 2005."

The Keele team examined the "trends in the annual prevalence and incidence of schizophrenia and psychoses, as measured by diagnosed cases from 1996 to 2005. Retrospective analysis of the General Practice Research Database (GPRD) was conducted for 183 practices in England, Wales, Scotland and Northern Ireland. The study cohort comprised almost 600,000 patients each year, representing approximately 2.3% of the UK population aged 16 to 44. Between 1996 and 2005 the incidence and prevalence of schizophrenia and psychoses were either stable or declining. Explanations other than a genuine stability or decline were considered, but appeared less plausible. In conclusion, this study did not find any evidence of increasing schizophrenia or psychoses in the general population from 1996 to 2005."

In the same decade that the typical THC levels of UK cannabis roughly doubled, and CBD content near vanished, the incidence of psychosis and schizophrenia in the UK either stabilised or declined.

The "skunk psychosis" fears being voiced by The Independent, Robin Murray, Charles Walker MP and Mary Brett of Cannabis Skunk Sense appear, however well-intentioned, to be without sound scientific foundation. Moreover, the drug control policies they champion are a source of the very evils they deplore. The prohibition approach appears to have stimulated a doubling of cannabis potency in the last decade or so.

Clarity from Anne Milton on the facts about cannabis and mental health is a welcome step towards a rational and compassionate drug policy for the UK."

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