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Friday, 31 August 2012

Teenagers, IQ risk and cannabis: cause and effect, bias or other explanations?

@HealthMed My first contact with study of the science of cannabis was as a medical student in Aberdeen undertaking a summer project in pharmacology: a new researcher, Roger Pertwee, was interested in the effects of bioactive ingredients of cannabis on brain regulation of temperature and muscle function.  Research since then by Pertwee and many others has identified the importance of endogenous chemicals, endocannabinoids, that are part of normal functioning of the brain and other parts of the body, for example in modulating mood and stimulating appetite. Abnormalities in endocannabinoid pathways have also been implicated in a wide range of medical conditions, including inflammation, obesity, cancer, cardiovascular disease as well as mood disorders. 

Now this week we have a report illustrating a new facet of potential harm from cannabis. In a long-term follow up study by scientists in Otago, at Duke University, USA and King's College London, lead by Madeline Meier (Duke), IQ and reported cannabis use was monitored over the 25 years from age 13 to 38 in the Dunedin Birth Cohort. Of particular interest, their study of over 1000 subjects included teenagers in whom IQ was checked before any cannabis exposure. Around 1 in 7 reported being regular cannabis users, 1 in 20 doing so at least weekly before the age of 18.

What did the investigators find? With no cannabis history, there was a small fall in IQ. However recurrent cannabis use was associated with an 8 point decline in IQ, comparable to that seen in early dementia. Importantly, this decrease in IQ was particularly marked when cannabis use began during teenage years. A further concern was that stopping cannabis use did not lead to recovery of the IQ loss. Commentary on the results has ranged from concluding that cannabis is harmful in teenagers but safe in adults, to more cautious notes that adolescent brains appeared more vulnerable to cannabis, without providing carte blanche for longer term safety of cannabis use in adults …

Are these fair interpretations? For further discussion of this long-term, prospective observational study, important caveats in its interpretation, and its potential implications, see my discussion posted on The Independent blogs site.

News of the 2013 EACPT Congress in Geneva

@HealthMed The EACPT's next biennial congress will be held in beautiful Geneva, 28th - 31st August in 2013 at the International Congress Centre of Geneva (CICG).
Registration will open 10th November 2012.
Abstract submissions will also open 10th November 2012 and will close 8th February 2013.
To receive updates on the congress before registering, you can submit your email address to the congress organisers.
Over 900 participants are expected to attend including health professionals, scientists, policy makers, biotechnology and pharmaceutical professionals and others interested in basic and clinical pharmacology, pharmacotherapy, drug discovery and development, regulatory affairs and related areas.
Geneva by the lake
Key themes at the congress will range from bedside pharmacology for special patient groups to pharmacology & toxicology, and pharmacology and society. Specific topics will include sessions on communicating with the public, ethics, safe prescribing, clinical trial design and governance, and health policy; new biologicals, translational medicine and pharmacogenetics; advances in personalised diagnostics to improve the safety and effectiveness of medicines, updates on new biological approaches to ocular disease, therapeutics of cardiovascular, cancer and inflammatory disease, clinical trial design and regulation, and drug safety and toxicology. 
The European Association for Clinical Pharmacology and Therapeutics (EACPT) has its origins in a working party in the early 1980s under the auspices of the World Health Organisation (WHO-Europe). The EACPT's next biennial congresses after Geneva 2013 are in Madrid 2015 and in Prague 2017. The EACPT also arranges summer schools, and other scientific and professional activities.

For more on the Congress, how to contact the organisers, and how to register to receive updates, see:
Congress Website:
Secretariat email: