"Despite the undoubted dangers associated with marijuana, the Beckley report concludes that it is far less harmful to users and to society in general than other illicit drugs such as heroin and cocaine, and far less damaging than the legal drugs tobacco and alcohol."
WHAT should we do to minimise the harm cannabis can cause to the health and welfare of users and to society at large? The answer, according to a report by a group of prominent academics and government advisers, is to change the law to allow the state to prepare and distribute the drug for recreational use.
This controversial proposal comes from a commission assembled by the Beckley Foundation, a British charity dedicated to exploring the science of psychoactive substances. "The damage done by prohibition is worse than from the substance itself," says Amanda Feilding, the founder of the Beckley Foundation.
The Beckley commission's ideas will be aired in March at a meeting in Vienna, Austria, of the UN Commission on Narcotic Drugs. The UNCND will report to a meeting of the UN general assembly later this year that will set international policy on drug control for the decade to come.
Marijuana is now the world's most widely used illicit drug. The latest figures from the UN Office on Drugs and Crime (UNODC) indicate that in 2006-7 some 166 million people aged 15 or above, or 3.9 per cent of this age group, used it regularly. Just 1 per cent of the world population uses other illegal drugs. Cannabis use is particularly widespread in rich countries. Around 40 per cent of Americans and one-third of Australians say they have tried it.
The evidence assembled by the Beckley commission left it in no doubt that cannabis damages the health of heavy users, especially those who start as teenagers. Such users are at increased risk of suffering from psychosis, and lung and heart disorders. They are also more likely to drop out of school early, be involved in traffic accidents, and be poor parents (see "How bad is it?"). The report also found evidence that cannabis may act as a "gateway drug", increasing the likelihood that users will go on to try more damaging drugs such as heroin or cocaine.
The report details a sharp rise in the potency of marijuana, with levels of delta-9-tetrahydrocannabinol (THC) - the chemical that gets cannabis users "stoned" - typically double to treble what they were a decade ago. This, it says, is partly the result of a switch to growing the plant indoors under continuous lighting.
Potent varieties, sometimes known as "skunk" or "sinsemilla", now make up 80 per cent of the market in the UK and the Netherlands according to a report published by the UK home office. These varieties also lack a compound called cannabidiol found in other cannabis strains, which when present may help prevent THC triggering psychotic episodes. About 9 per cent of regular cannabis users become dependent - experiencing withdrawal if they stop using - and suffer ill health as a result of their drug use, the Beckley authors say.
Despite the undoubted dangers associated with marijuana, the Beckley report concludes that it is far less harmful to users and to society in general than other illicit drugs such as heroin and cocaine, and far less damaging than the legal drugs tobacco and alcohol. There have been only two documented deaths from marijuana overdose, the report notes. This contrasts with 200,000 deaths from all causes each year attributed to other illegal drugs, 2.5 million deaths annually related to alcohol and 5 million to smoking.
Because possession of cannabis is illegal, its harmful consequences extend beyond possible damage to immediate health, the Beckley report points out. In particular, users are at risk of punishment and acquiring a criminal record. "If you don't think being arrested is a harm, you are unpersuadable," says criminologist Peter Reuter of the University of Maryland, a co-author of the report. "In the US, 750,000 people were arrested in 2006, and I think that's a substantial harm."