GB: Re-thinking cannabis
We need to discuss licensing the recreational use of cannabis, says Professor Roger Pertwee. "At the moment, cannabis is in the hands of criminals and I think it’s kind of crazy," he says. "We’re allowed to take alcohol. If it’s properly handled, cannabis probably won’t be more dangerous than that."
www.britishscienceassociation.org 14 septembre 2010
Professor Pertwee, Professor of Neuropharmacology at the University of Aberdeen, says that a group should be set up with expert pharmacologists, lawyers and police, amongst others, to thrash out the issue. He wants the "social, ethical, legal and economic factors in addition to current medical and pharmacological" factors to be taken into account: "We need a better solution than we have now."
Such a group would have to grapple with the way people could take cannabis. "Smoking it is probably not a good thing but there are alternatives. You needn’t produce smoke – you can vaporize it without burning it. You need to avoid younger people taking it: perhaps have a minimum age of 21. You might have to have it licensed so that you can only take it if it’s considered medically safe for you to do so. We have car licences, so why not cannabis licences?
Coping with risks
"It would be a challenge, but you could identify people who might be at risk of developing schizophrenia. Cannabis is one factor which increases the risk of schizophrenia, but only if it’s mixed with a bad childhood environment or a genetic predisposition to schizophrenia.
Professor Pertwee is addressing the British Science Association’s Festival of Science in Birmingham.
The problem of cannabis as a "gateway" drug is made worse, he says, because it’s illegal and therefore supplied by illegal dealers. They may say, one day, "I haven’t any cannabis but I have this white powder you can sniff."
"It’s important to consider drugs one by one and not lump them together," he says.
Cannabis in medicine
Our bodies produce some of the substances contained in cannabis. These are known as endocannabinoids, and they interact with our cells and seem to fine tune a range of functions, including the perception of pain and memory. This discovery "is expected to lead to the development of new and better medicines, for example for the relief of severe pain," says Professor Pertwee.
He and his colleagues have recently discovered that omega-3 unsaturated fatty acids in our diets, for example in fish oil, give rise to endocannabinoids.
In June this year, a cannabis-based medicine called Sativex was licensed in the UK to help relieve spasticity in patients with multiple sclerosis.
Side effects
Current research is trying to keep beneficial effects of cannabis-based pharmaceuticals but reduce unwanted side effects. One such drug, rimonabant, was licensed in 2006 for the treatment of obesity, but subsequently withdrawn because of concerns that it increased patients’ incidence of depression. It also increased the number of patients with suicidal tendencies.
The issue of recreational cannabis use, and self-medication with cannabis ("medical marijuana"), are both more complicated than the issue of pharmaceuticals derived from cannabis, says Pertwee. "The issues of recreational cannabis and of medical marijuana must not impede the development of cannabinoids as medicines," he says.
