Stories relating to February 1998 claims that World Health Organization suppressed findings about the relative safety of cannabis

Contents: press articles, report from Britain's New Scientist magazine

Toronto Globe and Mail

Marijuana flap gets pot boiling at WHO

Report that suggested drug less risky than alcohol, tobacco was suppressed

Tuesday, March 3, 1998 By Carolyn Abraham Medical Reporter

The World Health Organization is being forced to defend itself around the globe after excluding information from a recent report that suggests marijuana poses fewer health risks than alcohol and tobacco.

The Geneva-based agency said it dropped the findings of leading Canadian and Australian scientists from last December's final report on cannabis because the comparison between the drugs was scientifically unsound.

But in criticizing the work of internationally respected researchers, the WHO has not extinguished allegations that it had other motives.

Suspicion lingers that the WHO buckled under political pressure from certain countries that feared the findings would fuel the growing fight to legalize marijuana.

Much the way the International Olympic Committee was forced to assess its role in restricting social drugs after Canadian gold-medal snowboarder Ross Rebagliati tested positive for marijuana, the WHO is struggling to clarify its position as a scientific body immune to political interests in reviewing the illicit narcotic.

"We don't have any stake in the political debate," said Tokuo Yoshida, head of the WHO's drug management and policies division. "Our information is based on scientific and medical judgment, there was no such pressure from any government."

Mr. Yoshida said the WHO has been bombarded by phone calls and E-mail messages from all over the world seeking explanations since Britain's New Scientist magazine said the work had been suppressed and published excerpts of the missing information in February. Marijuana research has expanded dramatically since the WHO's 1982 cannabis report, as has the international thirst for information related to it. Its potential medicinal uses, its resurgence among teen-agers and the campaign to legalize it, prompted the WHO to commission a third report of the so-called soft drug in 1994.

Various international experts were asked to write reviews of the current research.

Dr. Robin Room, the chief scientist and sociologist at Ontario's Addiction Research Foundation, and Dr. Wayne Hall, an Australian scientist who has completed extensive marijuana research, were asked to compare the health and psychological risks of cannabis, alcohol, nicotine and opiates.

Dr. Room, who completed the paper in 1995, said he did not know the WHO had excluded their findings until the cannabis report was released.

"I do not agree with the decision not to include this," he said. "It is a relevant thing to put out there for public consumption -- the relative harm associated with these things. It is like studying the relative benefits of margarine or butter."

Their review concluded that certain risks associated with tobacco and alcohol have no equivalent in marijuana use. For example, it is possible to die from an alcohol overdose, but nearly impossible to die from an overdose of marijuana, Dr. Room said. Alcohol can cause cirrhosis, marijuana cannot. Marijuana is more likely to cause lung problems than is alcohol, but less likely than tobacco.

"The health concerns associated with alcohol and tobacco are more serious than that of marijuana usage," he said. "If that usage increases, the health risks will increase, but it's not clear by how much."

Cannabis fared better in five out of seven comparisons of long-term damage to health, based on current worldwide levels of usage. But the report also stated that cannabis "would be unlikely to seriously rival the public health risks of alcohol and tobacco even if as many people used cannabis as now drink alcohol or smoke tobacco."

Dr. Billy Martin, a pharmacologist at the Medical College of Virginia and a member of the WHO's advisory committee, said officials at the WHO were "very uncomfortable" when they first saw the findings.

"The WHO felt it could be misinterpreted without a fair discussion about the risks of all these other drugs," Dr. Martin said. "It wasn't a conspiracy or suppression. . . . I think they exercised their selection of what would be left out."

But the WHO searched out input on the report over the next 2«years, which Dr. Martin said did seem like an unusually long time. Mr. Yoshida said the draft report on cannabis was sent to more than 80 experts, agencies and institutions around the world.

"They came under tremendous pressure from some quarters and there are a lot of problems when politics enters into this," said one scientist familiar with the report.

But Mr. Yoshida insists officials at the WHO simply felt the work was contradictory and "too speculative" because there is a dearth of epidemiological research comparing the drugs.

"The comparison itself is very difficult to make. Cannabis is taken by smoking it, alcohol is drunk. At what doses should we compare alcohol and cannabis?" Mr. Yoshida said. "Is one joint of a marijuana cigarette equal to one beer?"

Dr. Room said he does not pretend their review is definitive since research in the area is always growing and evolving. "But fundamentally you can certainly argue the strength of the science," he said. "We make a lot of policy judgments on less-than-perfect information, but we do our best with what is available. It struck me as rather important information."

Mark Kleiman, a U.S. public-policy analyst at the University of California who has written on the cannabis debate, said it is predictable that alcohol has worse public-health risks than marijuana -- since about eight times as many people drink.

"I can certainly sympathize with the viewpoint that any findings favourable to marijuana usage will end up on the cover of High Times and used not merely to change the laws but to convince people to light up," Mr. Kleiman said.

But he said the WHO should frame the discussion that way and not chalk it up to bad science.

"Anyone who says Wayne Hall and Robin Room are capable of bad science is talking through their hat," Mr. Kleiman said.

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Toronto Star Fri, 20 Feb 1998

CANNABIS OBVIOUS THREAT TO HEALTH, AGENCY SAYS

GENEVA (Reuters) - The World Health Organization insisted yesterday that cannabis is a public health threat.

"It is obvious that the use of cannabis causes a number of health problems and that an increase in its use would make the situation worse," a WHO statement said.

It was defending itself against accusations that it suppressed a report that found cannabis safer than alcohol or tobacco.

Britain's New Scientist magazine said Wednesday that WHO officials in Geneva suppressed a comparison study of cannabis and legal substances because they feared it would give ammunition to the "legalize marijuana" campaign.

Instead, WHO said it dropped the analysis because it contained contradictions and "conclusions were not scientifically sound."

Tokuo Yoshida, in charge of narcotic drugs at the WHO, said cannabis is dangerous to health because it causes mind-altering activities in users.

"Cannabis is milder than LSD, of course," he said. "But it must not be used because it changes your judgement and thinking."

According to New Scientist, which published a special report on marijuana Wednesday, a leaked document about the analysis concluded that the drug posed less of a public health threat than alcohol or cigarettes, even if people consumed it on the same scale.

The magazine said researchers had found marijuana smoke did not lead to blocked airways or emphysema or impact on lung function and it was less addictive than alcohol or cigarettes.

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U.N. Report Leaked: Cannabis 'Safer Than Alcohol or Cigarettes' --

Source: The Guardian (UK) Contact: letters@guardian.co.uk Website: http://www.guardian.co.uk/ Pubdate: Thu, 19 Feb 1998 Author: Tim Radford, Science Editor

CANNABIS 'SAFER THAN ALCOHOL OR CIGARETTES'

UN report leaked

United Nations health chiefs suppressed a finding that cannabis is safer than either alcohol or tobacco, according to a report today.

A World Health Organisation report published in December was to have concluded that even if cannabis was consumed on the same scale as cigarettes and whisky, it would probably still be safer than either, but the passage was scrapped at the last moment, says the magazine New Scientist.

The comparison with alcohol and tobacco, the suppressed passage said, was made "not to promote one drug over another but rather to minimise double standards that have operated in appraising the health effects of cannabis".

The disputed passage was leaked to New Scientist after it was withdrawn, reportedly in response to pressure from the US National Institute on Drug Abuse and the UN International Drug Control Programme. It says: "In developed societies cannabis appears to play little role in injuries caused by violence, as does alcohol." It also says there is good evidence that alcohol can harm foetal development, while the evidence that cannabis can harm foetal development is "far from conclusive".

The WHO report does admit that, like heavy drinking, marijuana smoking can produce psychosis in susceptible people. It also says chronic cannabis smoking may contribute to cancers of the aerodigestive tract.

But one lung disease researcher, Donald Tashkin of the University of California at Los Angeles, found that volunteers who smoked three joints a day had much the same lung capacity and function as those who smoked none. However, dope smokers must inhale deeply and hold the smoke in the lungs, so they got a large dose of potentially damaging tar.

The leaked UN report comes at a time of renewed pressure to think again about drug policies.

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UK: Cannabis 'safer Than Alcohol'

Newshawk: as684@lafn.org (John Humphrey) Source: Telegraph, The (UK) Author: Sebastien Berger Contact: et.letters@telegraph.co.uk Pubdate: Thu 19 Feb 1998

CANNABIS 'SAFER THAN ALCOHOL'

A STUDY showing that cannabis is safer than alcohol or tobacco has been suppressed by United Nations health officials, it is reported today.

According to the New Scientist magazine, the analysis concluded that cannabis does less harm to public health than alcohol or cigarettes and would do so even if it were consumed in similar quantities to the legal drugs.

The comparison, written by marijuana experts, was due to appear last December in the World Health Organisation's first report on the effects of cannabis for 15 years.

It was withdrawn at the last minute after a furious dispute involving WHO officials, the report writers and external advisers. Sources quoted in the magazine claim that the WHO gave way to political pressure, with American drugs officials and advisers from the UN Drug Control Programme saying that the document would be seized upon by organisations campaigning for the legalisation of cannabis.

"In the eyes of some, any such comparison is tantamount to an argument for marijuana legislation," said one of the report's authors.

Another said that WHO officials "went nuts" when they saw the draft version. A leaked version of the report says the comparison was made "to minimise the double standards that have operated in appraising the health effects of cannabis".

On most points, cannabis was considered less harmful to health than alcohol, with the illegal drug playing little role in injuries caused by violence, unlike alcohol.

Evidence that cannabis could harm the development of babies in the womb was considered "far from conclusive", while the grounds for alcohol doing so were "good".

A WHO official said that the comparison was excluded because "the reliability and public health significance of such comparisons is doubtful".

4 January 1998: MPs to press for inquiry into cannabis 19 November 1997: BMA in cannabis prescription plea 19 September 1997: Straw attacks call to make cannabis legal 18 June 1997: Cannabis does no harm says Stoppard

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UK: Cannabis Campaign: Report Boost For Cannabis

Newshawk: Alan Randell Pubdate: Thu 18 Feb, 1998 Source: Independent, The (UK) Author: Charles Arthur, Science Editor Contact: Email: cannabis@independent.co.uk Mail: Independent on Sunday, 1 Canada Square, Canary Wharf, London E14 5DL England Editors note: The IoS Cannabis Campaign has web pages at http://www.independent.co.uk/sindypot/index.htm

REPORT BOOST FOR CANNABIS

Research has established that decriminalising marijuana does not lead to the use of harder drugs such as cocaine and heroin, and that teenagers and children are more likely to experiment with alcohol and tobacco.

Long-running surveys carried out in the Netherlands, where marijuana was decriminalised in 1967, have found that even in the age group where cannabis use is highest - those between 20 and 35, of whom 12.5 per cent are "regular" users - only 1.3 per cent had used cocaine in the previous month, with the majority of those being aged over 30.

The latest sample of more than 2,000 people in 1994 found that nobody under 20 had ever used heroin, and there were just four people who "regularly" used heroin, all aged between 25 and 50. Cocaine and heroin use are not legal in the Netherlands.

The findings, from ongoing surveys carried out over the past 10 years by the Centre for Drug Research at the University of Amsterdam among the city's residents, provide more ammunition for the Independent on Sunday's campaign to decriminalise cannabis in Britain.

It also shows that the Government's insistence that decriminalising the drug would be a catastrophe does not stand up to close examination.

A leading scientific magazine is expected tomorrow to publish further research which indicates that cannabis has fewer health effects than other legal drugs such as tobacco.

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UK: Blocked Report Says Cannabis Safer Than Tobacco And Drink

Newshawk: shug (shug@shuggie.demon.co.uk) Pubdate: Th, 19 Feb 1998 Source: The Scotsman Author: Jennifer Trueland, Health Correspondent Website: http://www.scotsman.com Contact: Letters_ts@scotsman.com

BLOCKED REPORT SAYS CANNABIS SAFER THAN TOBACCO AND DRINK

THE illegal drug cannabis is safer than tobacco and alcohol, according to a report which was suppressed by the World Health Organisation.

The analysis, which was due to be part of a report published last December on the harmful effects of cannabis, was withdrawn at the last minute after a dispute between WHO officials, the cannabis experts who drafted it and external advisers.

According to New Scientist magazine, the suppressed report concluded that not only did the amount of cannabis smoked worldwide do less harm to public health than drink and cigarettes, but that the same was likely to hold true even if people consumed it on the same scale as the legal substances.

In most of the comparisons made in the analysis, cannabis came out better or at least equal to the other drugs.

In an editorial, New Scientist said that decriminalisation of cannabis was inevitable. "Politicians will have to bite the bullet - dope will be decriminalised," it said.

Last night a Home Office spokesman said that the Government did not intend to review the position of cannabis, which is a controlled drug. The House of Lords has started its own inquiry, however, and a two-year investigation into the drug is being carried out by the Police Foundation.

But the evidence led to renewed calls for cannabis to be decriminalised.

Linda Hendry, Scottish spokeswoman for the Legalise Cannabis Campaign, said: "The New Scientist is saying what we already knew - that cannabis is not as harmful as other drugs like tobacco and alcohol. We welcome their findings and hope it adds to the debate."

The New Scientist also publishes data from the Netherlands, where possession of small amounts of cannabis was legalised in 1976.

According to results, although more people tried cannabis after it was legalised, the move did not increase the likelihood of people becoming long-term users.

Holland also had a lower percentage of cannabis and hard drug users than many other European countries, including Britain. The study also showed the number of hard drug addicts in Holland had not increased for a decade while their average age was rising.

The New Scientist said the controversial analysis was withdrawn because there were fears that it would give ammunition to the "legalise marijuana" campaign.

It is understood that advisers from the US National Institute on Drug Abuse and the UN International Drug Control Programme warned the WHO that it would play into the hands of groups campaigning to legalise marijuana, said the report.

Dr Maristela Monteiro, a scientist with the WHO programme on substance abuse, confirmed that the analysis was dropped from the report but denied the organisation had been pressured into doing it.

She said: "There were problems with that chapter. It was not a fair comparison from our point of view and from a public health perspective it was not very useful. We thought it was biased towards showing less harm from cannabis."

She said the WHO was working with the Addiction Research Foundation in Canada and planned to publish a book on cannabis in June.

The report also sparked repeated calls for further research into the potential effects of decriminalising cannabis. The British Medical Association, last year called for more research into the use of certain derivatives of cannabis for medicinal use., following some anecdotal evidence that the drug can help people with conditions including glaucoma and multiple sclerosis.

The Church of Scotland yesterday repeated its call for cannabis to be decriminalised. Ann Allen, convener of the board of social responsibility, said: "We do not want cannabis to be legalised but we wish to see those who have been caught taking it to be diverted from the criminal justice system and into rehabilitation programmes."

A spokesman for the Scottish Liberal Democrats said: "We welcome the study and would call on people to look calmly at it and make a reasoned judgment."

"We feel there should be a Royal Commission on drugs. We are the only party who has considered the issue seriously at all, and not just gone for the emotional line of instantly dismissing any idea that it should even be discussed.

"That, of course, stops short of any idea that it should definitely be decriminalised."

Peter Wishart, the Scottish National Party spokesman on drugs, said: "The SNP believe there's a case to be made for the decriminalisation of cannabis, but it is not an argument we are convinced by at this stage.

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New Scientist articles (These articles can be downloaded directly from the New Scientist web site: Website: http://www.newscientist.com/home.html )

Editorial: Let's Be Adult About This

Newshawk: Jim Rosenfield Source: New Scientist Editorial Contact: letters@newscientist.com Pubdate: 21 February 1998 Vol. 157 No. 2122 Editor: Alun Anderson

LET'S BE ADULT ABOUT THIS

When olympic officials decided last week to give errant snowboarder Ross Rebagliati his gold medal back, the cheers drowned out the boos. It was a minor scandal involving a minor sport, but it spoke volumes about the world's shifting relationship with its favourite illicit drug.

A decade ago, Rebagliati would have been ostracised regardless of whether cannabis was on the list of his sport's banned substances.

What's changed today is that our attitudes towards illegal drugs are becoming more sophisticated and discriminating. After thirty years of research into the harmful effects of cannabis, there can be no hidden dangers left to discover. We know that it is plain nonsense to regard cannabis as a performance-enhancing drug, just as it is a myth to think the substance rots the brain or leads inexorably to harder substances.

And despite the anti-dope propaganda that circulates in the US, most people are thankfully well aware that no great social disaster has befallen the Netherlands, where cannabis has been sold openly in coffee shops for years. It would take a perverse mind to twist the data from Amsterdam into a argument for continued prohibition (see this week's Special Report on Marijuana).

While no sensible person believes cannabis is totally safe, even police chiefs back moves to decriminalise the drug. Only the politicians still seem irrationally terrified by the idea of any relaxation in the law: they think they can continue in the old way, lumping all drugs together.

Before anyone decides what decriminalisation should mean in practice, however, we must take a hard look at every aspect of cannabis, from its long-term effects on the brain to the social effects of legal reform. If there is to be change, how far should we go? At one extreme, we could go Dutch, at the other, we might decide to do little more than rationalise the existing legal penalties and allow doctors to prescribe marijuana to people with serious illnesses.

And if reefers are to be doled out on the NHS, for example, what information should go on the side of the packet? Or should we wait until researchers have figured out how to put cannabis into aerosol devices?

Such complexities are why Britain's House of Lords was right to defy Home Secretary Jack Straw recently and launch its own inquiry--and why US drugs supremo Barry McCaffrey was right to commission the US National Academy of Sciences to report later this year on the harmful as well as the medicinal effects of cannabis.

Conversely, the pressing need for an open debate about cannabis is precisely why the WHO was so wrong to bow to political pressure and expunge from a recent report an informative if controversial comparison of the harms caused by different drugs including alcohol (see this week's news section).

Of course, ever since the splendidly named Indian Hemp Drugs Commission of 1894, independent panels have been politely saying that the evils of cannabis have been exaggerated--and politicians have been politely ignoring them. Change is looking more possible now because the forces pressing for legal reform come with unprecedented levels of popular support.

In Britain, Tony Blair and his Cabinet can always discard the opinions of the House of Lords, but they are fools to ignore opinion polls in tabloid newspapers which suggest a majority of the nation is now in favour of legal change.

And the US government may have already met its Waterloo on the dope issue. In recent months, it has been locked in a bitter and futile dispute with the states of California and Arizona which have independently ruled that doctors should be allowed to prescribe marijuana with impunity. Even in America, threatening vulnerable patients and their doctors with legal action is no vote winner.

Something will have to give, and the best bet is that California and Arizona will triumph in the end. If they do, it will be the beginning of the end for outlawing marijuana because where the US government goes, the rest of the world will quietly follow.

None of this, of course, means cannabis is as safe as some of its advocates claim. But neither, as our special report shows (see p 23), are the opposing claims of the world's biggest funder of research into marijuana to be taken at face value.

Campaigners and pressure groups can be forgiven for trading propaganda, but we should expect world famous scientific organisations like the US National Institute on Drug Abuse to evaluate honestly the research that has been done.

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Marijuana Special Report: Opening Comments

Pubdate: Thu 19 Feb 1998 Source: New Scientist Contact: letters@newscientist.com

OPENING COMMENTS

Only one thing is certain about the great marijuana debate: whether you are Britain's prohibition-mad Home Secretary, or a stoned ex-hippy who would like to dish out the drug for free, you are likely to have a lot more opinions than facts.

Past commissions and reports have tried to clear the clouds of unreason but have been universally ignored. This week we make our own attempt to tackle the key issues, including the latest findings from the Netherlands where possession of small amounts of marijuana has been legal for a decade. Our report homes in on four key claims frequently made by the US National Institute on Drug Abuse. As its name implies, this government institute researches (and spends) hard in pursuit of the harmful effects of drugs. Its data also have a vast influence on UN policy. But as the pages that follow reveal, simple statements are never quite as simple as they seem . . . ********

Marijuana Special Report: Drop In With Dr Dave

Newshawk: Zosimos (mjc1947@cyberclub.iol.ie) Pubdate: Th, 19 Feb 1998 Source: New Scientist Contact: letters@newscientist.com Website: http://www.newscientist.com/home.html

DROP IN WITH DR DAVE

To find out what is happening on the front lines of marijuana addiction and treatment, Jonathan Knight spoke with David Smith, founder and president of the Haight Ashbury Free Clinics in San Francisco. When Smith opened his first clinic in 1967, the Haight Ashbury district was at the epicentre of American hippie counterculture and drug experimentation.

Today the Clinics treat 50,000 people a year at 22 sites in the Bay Area.David Smith also holds a professorship in toxicology at the University of California's San Francisco Medical Center and consults to the White House office on drug abuse policy.

How do you know when someone is addicted to a drug, and is cannabis truly addictive?

"Addiction used to be defined in terms of the severity of the withdrawal. Then we started seeing people who used amphetamines compulsively. But their withdrawal was just a mild crash. They'd fall asleep or perhaps get a little depressed.

That's when I coined the idea of the three Cs: Compulsion, loss of Control, and Continued use despite adverse consequences, as a definition of addiction.

Similarly for cannabis, withdrawal was characterised by anxiety and insomnia. It wasn't significant physical withdrawal, but that didn't mean it wasn't addicting. We would see people use compulsively every day, stop going to school, and spend all their money on marijuana. So the toxicity was lower than for heroine, but it still fit in to our definition of addiction.

Has the pot that's available on the streets become stronger?

The tobacco industry used DNA technology to increase the amount of nicotine in tobacco plants, and the cannabis growers do the same thing. They market it on the street as more potent and charge more for it. The legalisation people say that's not happening. But then are the dealers fraudulent? That seems illogical, cause the consumer thinks the stuff is more potent and is willing to pay more money for it.

And is it more addictive?

Of course it's more addictive, it's pharmacological logic. If you increase the power, it's going to be more addicting. But there's no way to know if a higher percentage of users are becoming addicted, or if only those who are addicted use stronger stuff. The people we see are smoking potent forms of marijuana, they are spending a significant amount of their income on it, they are suffering psychotic reactions, anxiety and depression. But if you smoke a joint at the Filmore auditorium on a Friday night and have a wonderful time, you don't go see the Haight Ashbury clinic. And we don't know how many people like that are out there.

Should cannabis be made legal?

I'm an opponent of marijuana legalisation. I don't want people to go to jail, I want them diverted to treatment, but I also don't want more marijuana available in the street. If marijuana were legalised I believe the tobacco companies would be the main distributors of it. And they would target youth as they did for tobacco. You would have the equivalent of Joe Camel for marijuana.

I prefer medicalisation: demand reduction through education and treatment. For example, 80 per cent of the people in the criminal justice system have drug abuse problems but only 5 per cent get any treatment now. Medicalisation puts much greater emphasis on treatment. If you get busted for smoking while driving, you get diverted to treatment, not jail. We've gone about as far as we can go with the criminal justice approach.

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Marijuana Special Report: Some References

Newshawk: Zosimos (mjc1947@cyberclub.iol.ie) Pubdate: Thu 19 Feb 1998 Source: New Scientist Author: Debora Mackenzie Contact: letters@newscientist.com Website: http://www.newscientist.com/home.html

SOME REFERENCES

Marijuana Use in College Students, H. G. Pope & D. Yurgelun-Todd, JAMA February 21 1996-Vol 275 No.7

Effects of Chronic marijuana use on human cognition, R. I. Block and M. M. Ghoneim, Psychopharmacology (1993) 110:219-228

Comparative Effects of Alcohol and Marijuana on Mood, Memory and Performance, S. J. Heishman, K. Arasteh and M.L. Stitzer Pharmacology Biochemistry and Behavior, Vol 58, No.1 pp 93-101, 1997

Marijuana Intoxication and Brain Activation in Marijuana Smokers, R. J. Mathew, W. J. Wilson, R. E. Coleman. T. G. Turkington, T. R. DeGrado, Life Sciences, Vol 60 No.23 pp 2075-2089, 1997

Relationships between frequency and quantity of marijuana use and last year proxy dependence among adolescents and adults in the United States, K. Chen, D. B. Kandel, M. Davies, Drug and Alcohol Dependence 46 (1997) 53-67

Cognitive Correlates of Long-term Cannabis Use in Costa Rican Men, J. M. Fletcher, J. Bryan Page, D. J. Francis, K. Copeland, M. J. Naus, C. M. Davis, R. Morris, D. Krauskopf, P. Satz, Arch Gen Psychiatry Vol 53, Nov 1996, 1051

Heavy Habitual Marijuana Smoking Does Not Cause an Accelerated Decline in FEV1 With Age, D. P. Tashkin, M. S. Simmons, D. L. Sherrill, and A. H. Coulson, American Journal of Respiratory and Critical Care Medicine Vol 155, pp 141-148, 1997

Marijuana and Cocaine Impair Alveolar Macrophage Function and Cytokine Production, G. C. Baldwin, D. P. Tashkin, D. M. Buckley, A. N. Park, S. M. Dubinett and M. D. Roth, American Journal of Respiratory and Critical Care Medicine Vol 156, pp 1606-1613, 1997

Marijuana Myths Marijuana Facts a review of the scientific evidence, Lynn Zimmer and John P. Morgan, published by The Lindesmith Center, New York 1997

Cannabis: a health perspective and research agenda WHO Programme on Substance Abuse, WHO/MSA/PS7.4

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Marijuana Special Report: A Safe High?: Claim One

Pubdate: Thu 19 Feb 1998 Source: New Scientist Contact: letters@newscientist.com Website: http://www.newscientist.com/home.html

A SAFE HIGH?

Claim ONE: "Critical skills related to attention, memory and learning are impaired among heavy users of marijuana . . ."

Most people think of marijuana users as dreamers with the attention span of a gnat and no memory worth the name. Wrong. The picture emerging from psychology labs is that there is at most a kernel of truth in this stereotype, while some studies find no evidence of even subtle mental impairment in heavy users. And even those that do are open to a range of interpretations -- not necessarily worrying to marijuana users.

Take the latest findings on which the above claim is based. Harrison Pope and his team at Harvard University compared 65 college students who smoked marijuana daily with a control group of students who smoked it most every other month. After a drug-free day, the subjects completed a range of standard mental tests. Mostly, differences between the two groups were slight. When it came to remembering lists of words, for example, the heavy users recalled about 1 in 10 fewer words than the light users.

But in one test the heavy users underperformed more noticeably. The test involved watching and mimicking the simple rules used by an experimenter to match cards with coloured shapes on them, and then adapting whenever the rule changed. Students who rarely smoked marijuana mistakenly carried on with the old sorting rule on about 5 out of 100 occasions, while heavy users made about 8 mistakes. Pope takes this seriously. "In the real world," he says, "people have to deal all the time with situations in which rules are changing..."

Fine. But over the years, much stronger claims have surfaced: heavy marijuana users do badly at work or school, are more likely to be delinquent and develop psychiatric problems, or have abnormal brain waves. Time and again, however, such studies encounter the same objection: are the problems caused by smoking marijuana, or is it just that people with problems are more likely to end up using marijuana heavily?

In the case of delinquency, schizophrenia and mental illnesses, the balance of the evidence points to the second explanation. Marijuana doesn't cause the problems, although it may make them worse. Some schizophrenics, for example, are drawn to the drug because it eases their sense of alienation. And most researchers now accept that the evidence linking marijuana to abnormal brain waves vanishes when people with psychiatric problems, illnesses or a history of general drug abuse are excluded from studies.

But what about subtler problems like the card sorting deficiencies? After all, it might just be that smart college students tend to smoke lightly while others smoke heavily. In which case the card sorting results may have little to do with marijuana.

Here opinions diverge. Pope believes the deficiency does have something to with marijuana because his team controlled for such obvious things as IQ differences, psychiatric histories and heavy use of other drugs. But others are not convinced. What worries some critics is that in this study, as in others, the women drug users did so much better than the men in most tests.

Deviant males

"I know of no reason why there should be a gender difference in cognitive response to cannabis," says John Morgan, a pharmacologist at the City University of New York Medical School and co-author of a controversial new book advocating decriminalisation, Marijuana Myths Marijuana Facts. Morgan believes the reason the males underperform in such studies is that they are "deviant" in subtle ways that escape the researchers' notice.

And what if the poor test results do turn out to be linked to marijuana? It doesn't automatically follow that heavy marijuana use is causing long-lasting brain damage. One possibility is that, deprived of their favourite drug for a day, heavy users suffer withdrawal symptoms or become so grumpy and distracted that they do badly in tests. Another is that a single drug-free day is not long enough for the effect of their last smoke to have disappeared. The Harvard team's follow-on experiments, in which marijuana users are being tested over a 28-day "dry" period, should provide answers.

Other research suggests that evidence of dramatic mental decline is unlikely to be found, even as a result of long-term heavy use. Over the past 25 years, Jack Fletcher at the University of Texas in Houston and his colleagues have been visiting Costa Rica to test the mental skills of very heavy users. Although some of them have smoked 10 joints a day for more than 30 years, their ability to learn and remember lists of words is only mildly impaired (see diagram below). And even when struggling with more demanding tasks, such as recalling information while pressing a tapper as fast as possible, their scores fall well within the normal range.

(image) Spot the difference: What cannabis does to memory skills

"The effects are subtle and subclinical," says Brian Page, an anthropologist from the University of Miami, who was involved in the study. "Although they could be bad for somebody who's trying to be an arbitrage trader or Wall Street lawyer." And, Page adds: "People who sell bicycles had better not ride while under the influence."

Or at any rate common sense suggests they should not. The verdict from research into the impact of marijuana on road safety skills is less clear. In Britain as many as 1 in 10 motorists involved in serious accidents test positive for cannabis. And figures as high as 37 per cent have emerged from studies in urban areas of the US. However, many of these drivers also test positive for alcohol, and even the cases involving just cannabis cannot be equated with people driving under the influence because the drug lingers so long in the body.

In driving simulators, marijuana does impair visual skills and mental dexterity. But studies of actual driving show that even high doses of marijuana have less impact than alcohol, perhaps because smoking it doesn't usually make people so reckless. In one study, low doses of marijuana made drivers more cautious.

The same broad message is likely to be true for the subtler, longer-lasting effects of marijuana on the brain. Researchers like Pope and Morgan may look at the data very differently, but they agree about one thing: heavy boozing is worse for your neurons than dope.

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Marijuana Special Report: Claim Two

Pubdate: Thu 19 Feb 1998 Source: New Scientist Contact: letters@newscientist.com Website: http://www.newscientist.com/home.html

MARIJUANA SPECIAL REPORT: CLAIM TWO:

"More than 120 000 people in the US seek treatment each year for their marijuana addiction . . ."

After years of decline, marijuana use among teenagers is now climbing rapidly in almost every industrialised nation. Will this create a generation of cannabis addicts?

The middle classes who enjoy a smoke once or twice a week may laugh at the idea. But doctors who treat the minority of users who have lost control take it more seriously. The pragmatic question is how big is this minority and would it expand if the drug was decriminalised or even legalised? The experience of the Netherlands (see Vraag een Politeagent) suggests the answer to the second question is "no". The first question is tougher.

At the very least, NIDA's figure of 120 000 cannot be taken seriously. It includes people who are arrested for cannabis offences and then given the chance of going into treatment as an alternative to prosecution, as well as workers who test positive for cannabis in random urine tests and opt for rehabilitation rather than being fired. The figures don't tell us how many people really get hooked.

At Columbia University in New York, addiction epidemiologist Denise Kandel has been taking a different tack. She has been analysing data collected every year in the US National Household Survey on Drug Abuse. And she concludes that subtle symptoms of dependence are more widespread among teenage users than previously thought.

Shocking statistic

About 15 per cent of teenagers who smoke marijuana report three or more "symptoms" of dependence from a list of six possible symptoms. They range from "feeling dependent" or being unable to cut down on consumption to using ever larger amounts of cannabis to get the same effect. Applying these same measures to alcohol, it turns out that marijuana is just as addictive as alcohol for adults and even more so for teenagers (see below). That shocks most marijuana users, but not Kandel, who believes kids may be unusually "sensitive" to marijuana for biological as well as social reasons. The way she sees it, the reason we have so many alcoholics is simply that there are so many people drinking.

(image) Days of depence: marijuana's addictive powers wane with age

The problem with this kind of research is that it all depends on what is meant by addiction. A drug addict is usually seen as a person liable to both withdrawal symptoms and long-term damage to their health. But Kandel's self-report criteria are based on a broader definition. If we applied them to coffee, vast numbers of us would qualify as addicts. Similarly, many people might describe themselves as "addicted" to shopping or television or chocolate. Kandel's analysis suggests young marijuana smokers are more likely to show symptoms of dependence than their beer-swilling contemporaries, but it doesn't tell us which substance is the more dangerously addictive.

What is clear is that as users enter their 20s, they report this dependence far less frequently. And of the people who are still smoking the drug in their 50s, fewer than one in 30 qualify in her analysis as being dependent. Addiction rates for nicotine follow the opposite trend.

This leads to what is perhaps the most telling statistic about the addictive powers of cannabis: more than 90 per cent of people who have ever used the drug have long since quit. While most people continue drinking and cigarette smoking long after the first flush of youth, people drop the weed in droves after the age of 30.

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Marijuana Special Report: Claim Three

Pubdate: Thu 19 Feb 1998 Source: New Scientist Contact: letters@newscientist.com Website: http://www.newscientist.com/home.html

MARIJUANA SPECIAL REPORT: CLAIM THREE:

"Smoking marijuana can lead to abnormal functioning of lung tissue . . ."

Smoking a couple of joints is as bad for your lungs as consuming a whole packet of cigarettes, say the anti-dope brigade. Their opponents say smoking marijuana has never caused anyone to die from lung cancer. So, is marijuana smoke more -- or less -- dangerous than tobacco smoke?

The person to ask is Donald Tashkin, a lung expert at the University of California at Los Angeles. For the past 15 years, Tashkin's team has been keeping a close eye on the respiratory systems of more than 130 regular marijuana smokers, comparing them with groups of people who smoke either just tobacco, tobacco and marijuana, or nothing at all. It's the biggest study of its kind in the world. And the results so far suggest that in some respects, yes, marijuana is more dangerous than cigarettes. But in one important respect, joints may actually be better for you -- especially if you're an athlete.

First, the bad news. While the cigarette smokers in the study were ploughing through 20 or more a day, the marijuana smokers seldom consumed more than three or four joints. Despite this, the marijuana smokers coughed and wheezed as much as the cigarette smokers. In both groups, about one in five people complained of coughing up phlegm and suffering bouts of bronchitis.

And when it came to cellular damage to the lungs, there was also little to choose between them. Both groups had too many mucus-secreting cells lining their airways and too few hair cells, and both groups showed evidence of abnormalities in cell nuclei and changes in genes known to have an early role in the development of cancers.

The similarity may seem puzzling given that the marijuana smokers were consuming so much less plant material. But there are good reasons for it, says Tashkin. The first is that joints yield up to three times the tar of cigarettes because they are more loosely packed and don't have filters. The second reason is that marijuana smokers inhale more deeply and hold their breath longer.

"We actually quantified this and found that the breath-holding time was increased about fourfold," says Tashkin. "That resulted in about a 40 per cent greater deposition of tar." Tashkin's final factor -- contested by some researchers -- is that marijuana smoke is richer in benzopyrene and other polycyclic aromatics known to trigger cancerous changes in cells.

So smoking marijuana can cause lung cancer, after all? Well, maybe. Despite the gloomy cell biology, epidemiologists have so far failed to find a link between marijuana and serious lung diseases. That might be because there isn't one. Or it might be because "the marijuana epidemic" (as Tashkin calls it) is still young and the people who started smoking in the 1960s haven't reached an age when cancers become common.

Meanwhile, some researchers are worried about another aspect of marijuana smoke -- its ability to interfere with immune cells that help to fight off lung infections. Tashkin's team has just discovered that immune cells isolated from the lungs of marijuana users are unusually bad at killing bacteria, 35 per cent worse, in fact, than similar cells taken from cigarette smokers. The marijuana-exposed cells were also below par at producing molecules needed to mount inflammatory responses. In normal marijuana smokers, the effects may be too slight to make much difference. Tashkin fears, however, that the same might not be true in people with AIDS, many of whom use cannabis to stimulate their appetites.

Footballer's fancy

There's some good news, though, for dope-smoking cricketers and footballers: marijuana smoke won't lead to blocked airways or emphysema. Despite all the cellular changes noted by Tashkin's team, the researchers found that even heavy smoking of marijuana had no impact on any physical measure of lung function. In fact, among their subjects, smoking three joints per day caused no greater rate of decline in lung capacity and the ability to breathe than smoking no marijuana per day.

And the reason for this silver lining? It could well be back to those sluggish immune cells, speculates Tashkin: "If cannabis impairs the ability of immune cells to produce inflammatory cytokines, you might be spared mucosal damage in peripheral airways."

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Marijuana Special Report: Claim Four

Pubdate: Thu 19 Feb 1998 Source: New Scientist Contact: letters@newscientist.com Website: http://www.newscientist.com/home.html

MARIJUANA SPECIAL REPORT: CLAIM FOUR:

"Marijuana causes long-term changes in the brain similar to those seen with other drugs of abuse . . ."

Back in the 1970s, animal experiments led to groundless fears that marijuana blew holes in brain tissue. The experiments organisations like NIDA now fund are more sophisticated but the controversy still rages.

George Koob, an addiction researcher from The Scripps Research Institute in La Jolla, California, claims the new message from the animals is simple: "The more we discover about the neurobiology of addiction the more common elements we're seeing between THC (tetrahydrocannabinol, the main active ingredient in cannabis) and other drugs of abuse." And for Koob, one of these newly discovered "common elements" is marijauna's ability to trigger chemical changes in the brain that lead to strong withdrawal symptoms.

In humans, some researchers claim to see clear evidence of insomnia, anxiety and even flu-like symptoms in heavy cannabis users who abstain. But if there's a consensus, it's that symptoms are mild and variable. By contrast, Koob's rats are shivering wrecks. Does this mean marijuana is more addictive than we think?

Not a bit of it, says Roger Pertwee, a university pharmacologist and president of the Cannabinoid Research Society. That's because those symptoms aren't so much observed as manufactured. The animals are injected with high doses of THC, then injected with a second chemical to block cannabis receptors in the brain. Without the block, the sharp withdrawal symptoms can't be seen because cannabis clears so slowly that even heavily doped rats are likely to experience a gentle wind down.

Another debate rages over animal studies into the short-term effects of marijuana on brain chemistry. Heroin, cocaine, alcohol and nicotine all trigger a surge in the chemical dopamine in a small midbrain structure called the nucleus accumbens. Many researchers regard this as a hallmark of an addictive substance.

Last year, experiments showed that cannabis presses the same dopamine button in rats, leading to claims that the drug must be more addictive than previously thought. To critics, it is just another example of those old exaggerated fears.

What nobody tells you, says John Morgan, a pharmacologist at City University of New York Medical School, is that rats don't like cannabis. It's easy for them to get hooked on heroin or cocaine -- but not marijuana. Nor, Morgan claims, are researchers exactly open about awkward observations, such as the fact that there are plenty of nonaddictive drugs that stimulate dopamine in the brain.

It's easy to understand why biologists want to find simple chemical traits that are shared by all addictive drugs. Unfortunately, the differences are as important as the similarities when it comes to weighing the relative risks and pleasures involved in taking drugs. And subjectively at least, the intense rush of cocaine and orgasm-like high of heroin have little in common with dope's subtler effects.

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Marijuana Special Report: High Anxieties

Pubdate: Thu 19 Feb 1998 Source: New Scientist Contact: letters@newscientist.com Website: http://www.newscientist.com/home.html

HIGH ANXIETIES

What the WHO doesn't want you to know about cannabis

Health officials in Geneva have suppressed the publication of a politically sensitive analysis that confirms what ageing hippies have known for decades: cannabis is safer than alcohol or tobacco.

According to a document leaked to New Scientist, the analysis concludes not only that the amount of dope smoked worldwide does less harm to public health than drink and cigarettes, but that the same is likely to hold true even if people consumed dope on the same scale as these legal substances.

The comparison was due to appear in a report on the harmful effects of cannabis published last December by the WHO. But it was ditched at the last minute following a long and intense dispute between WHO officials, the cannabis experts who drafted the report and a group of external advisers.

As the WHO's first report on cannabis for 15 years, the document had been eagerly awaited by doctors and specialists in drug abuse. The official explanation for excluding the comparison of dope with legal substances is that "the reliability and public health significance of such comparisons are doubtful". However, insiders say the comparison was scientifically sound and that the WHO caved in to political pressure. It is understood that advisers from the US National Institute on Drug Abuse and the UN International Drug Control Programme warned the WHO that it would play into the hands of groups campaigning to legalise marijuana.

One member of the expert panel which drafted the report, says: "In the eyes of some, any such comparison is tantamount to an argument for marijuana legalisation." Another member, Billy Martin of the Medical College of Virginia in Richmond, says that some WHO officials "went nuts" when they saw the draft report.

The leaked version of the excluded section states that the reason for making the comparisons was "not to promote one drug over another but rather to minimise the double standards that have operated in appraising the health effects of cannabis". Nevertheless, in most of the comparisons it makes between cannabis and alcohol, the illegal drug comes out better--or at least on a par--with the legal one.

The report concludes, for example, that "in developed societies cannabis appears to play little role in injuries caused by violence, as does alcohol". It also says that while the evidence for fetal alcohol syndrome is "good", the evidence that cannabis can harm fetal development is "far from conclusive".

Cannabis also fared better in five out of seven comparisons of long-term damage to health. For example, the report says that while heavy consumption of either drug can lead to dependence, only alcohol produces a "well defined withdrawal syndrome". And while heavy drinking leads to cirrhosis, severe brain injury and a much increased risk of accidents and suicide, the report concludes that there is only "suggestive evidence that chronic cannabis use may produce subtle defects in cognitive functioning".

Two comparisons were more equivocal. The report says that both heavy drinking and marijuana smoking can produce symptoms of psychosis in susceptible people. And, it says, there is evidence that chronic cannabis smoking "may be a contributory cause of cancers of the aerodigestive tract".

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Marijuana Special Report: Vraag Een Politieagent . . .

Pubdate: Thu 19 Feb 1998 Source: New Scientist Author: Debora Mackenzie Contact: letters@newscientist.com Website: http://www.newscientist.com/home.html

VRAAG EEN POLITIEAGENT . . .

Go ahead, ask a cop for dope. The Dutch don't mind

It is a weird experience. You walk up to a Dutch policeman, and ask where to get some marijuana. You are smilingly directed to the nearest "coffee shop", where the menu offers everything cannabinoid from something called Space Cake to Northern Lights, a local weed.

In much of the world, this could never happen: the penalties for using cannabis are severe. But in 1976, the Dutch legalised the possession of small amounts. What has happened since? Some say that crime has soared, schoolchildren drop out, and heroin addiction is rife. Others insist the Netherlands is a stoned paradise of peace and love.

"I've visited their parks. Their children walk around like zombies," says Lee Brown, head of the US Office for National Drug Control Policy. "Hard drug use -- heroin and cocaine -- has declined substantially," says Paul Hager of the Indiana Civil Liberties Union.

Most comments seems to seem to depend on the speaker's politics. So what is the truth about the great Dutch cannabis experiment?

Hard addicts

"There was no immediate increase in cannabis use after 1976," says Arjan Sas of the Centre for Drug Research at the University of Amsterdam. "Trends in use have generally been the same as in other countries." The percentage who regularly use either cannabis or hard drugs is lower in the Netherlands than in many European countries, including Britain. And the number of hard drug addicts in the Netherlands has not increased for a decade, while their average age is rising.

Dutch statistics, however, are far from conclusive. The first national survey of drug use in the Netherlands is only just being done. There have been smaller-scale studies of particular towns or age groups but comparing them is fraught with statistical problems.

Nonetheless, Dirk Korf of the Institute of Criminology at the University of Amsterdam has used the smaller studies to estimate that 3 per cent of Dutch people had used cannabis at least once in 1970, rising to 12 per cent in 1991. The best guess for 1998 is 14 per cent.

Most of that increase, says Korf, is because "lifetime use" figures are cumulative: people who had used it in 1970 are still around, and are joined by younger users over time. More to the point, he says, is to compare the number of teenagers who start using cannabis. In 1970, he estimates that 20 per cent of all Dutch 18-year-olds surveyed had used it at least once; in 1980, that had fallen to 15 per cent. By 1987, it was 18 per cent, an increase, Korf says, that mirrors the increase in the number of coffee shops in the mid-1980s. Now, about 30 per cent of Dutch 18-year-olds are said to have tried cannabis, though some researchers think that is an overestimate based on studies of Amsterdam where coffee shops abound.

But did more people try cannabis after it was legalised? It seems so. At the Centre for Drug Research, Sas and Peter Cohen divided Amsterdamers surveyed in 1987, 1990 and 1994 into two groups -- those that were born before 1958, who were 18 or older in 1976, and those that were born after 1976, for whom cannabis has always been legal. Only 19 per cent of the oldies had tried cannabis, compared with 38 per cent of the younger group.

That difference could be partly misleading. Dutch surveys show that the vast majority of people who use cannabis do so almost exclusively in their 20s. The drug became common in the Netherlands in the mid-1960s, so for the older group members who were already more than 30, it was too late. Nonetheless, the data suggest that more people did try cannabis after decriminalisation.

But what counts, though, says Sas, is how many continue to use it. In Amsterdam, 55 per cent of people who say they have tried cannabis only end up using it a couple of dozen times or less. The rest may have used it more often, but more than half have not used it in the past month. The data show, says Sas, that legalising cannabis may make you more likely to try it, but it does not make it more likely that you will continue to use it.

But it is by no means certain that the first half of that conclusion is correct. Korf finds that surveys of the number of Germans who use cannabis "virtually parallels" the peaks and troughs in Dutch surveys between 1970 and 1990, even though Germany has prohibited cannabis throughout the period. Surveys of young Americans in the 1970s and 1980s found "substantially higher prevalence rates" than in Holland, peaking at 50 per cent of high-school seniors in 1980, although the US was strongly prohibitionist.

Legal immunity

Since then, says Korf, there have been no discernible differences in use between US states that have decriminalised, and those that have not, while cannabis use has increased in the US and Western Europe since 1990, regardless of the legal framework. "There is no appreciable causal connection between the Dutch decriminalisation of cannabis and the rate at which cannabis use has evolved," Korf concludes.

Last year, Robert MacCoun of the University of California at Berkeley and Peter Reuter of the University of Maryland, compared trends in cannabis use in the US, Norway (which bans it) and the Netherlands. They also concluded that "reductions in criminal penalties have little effect on drug use, at least for marijuana".

While the 1976 legislation may have had little effect on cannabis use, how effective has it been in its main goal of keeping people off harder drugs? The Netherlands has fewer addicts per capita than Italy, Spain, Switzerland, France or Britain, and far fewer than the US. Frits Knaak of the Trimbos Institute in Utrecht, the Dutch national institute for mental health and addiction, says the number of hard drug addicts in the country has been the same for a decade because fewer young people are joining their ranks. The average Dutch junkie is now 44 years old and only 0.3 per cent of Dutch teenagers had tried cocaine in 1994, compared with 1.7 per cent in the US. In the Netherlands, virtually everyone who uses drugs tries cannabis first, and many seem content to go no further.

Cannabis addiction and other problems are uncommon. "The number of cannabis users treated in drugs outpatient facilities is low," says Knaak. "In 1996, there were only 2000 [patients] in the whole country -- just 0.3 per cent of all Dutch cannabis users."

Of those, 42 per cent "are also having trouble with alcohol or other drugs - -- the rest usually just need counselling to help change their lifestyle", says Sas. Most people who find cannabis causing trouble with concentration or memory at work or school, he says, apply rules, like no smoking on week nights, or they limit their intake.

This self-policing seems to work. Dutch teenagers get among the highest scores in the world on international science and mathematics tests. If there are serious problems caused by legalising marijuana, then twenty-plus years of the Dutch experiment has not revealed what they are.

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'Grass' Study Suppressed: Magazine

Newshawk: Dave Haans Source: Toronto Star Contact: lettertoed@thestar.com Website: http://www.thestar.com/ Pubdate: Thursday, February 19, 1998

EDITORS NOTE: Thanks to the many newshawks who sent items on this story. Most likely it made quite a few major daily newspapers. If any made an editorial statement on the news, please send it to editor@mapinc.org

Due to a technical problem Thursday afternoon and evening we may have missed a few posts to editor@mapinc.org (Newshawks: If you had a post bounce, please resend it, thank you!)

Readers who like to send letters to the editor may find this story an easy one to send something on to their local newspaper, if they covered it or not. - Richard Lake, MAPNews Sr. Editor

'GRASS' STUDY SUPPRESSED: MAGAZINE

LONDON, Feb 18 (Reuters) - Officials at the World Health Organisation in Geneva suppressed a report confirming that cannabis is safer than alcohol or tobacco, New Scientist magazine said on Wednesday.

The WHO's summary report on cannabis, its first in 15 years, was published in December but the magazine claims a comparison study of cannabis and legal substances was dropped because the organisation feared it would give ammunition to the ``legalise marijuana'' campaign.

``It is understood that advisers from the U.S. National Institute on Drug Abuse and the U.N. International Drug Control Programme warned the WHO that it would play into the hands of groups campaigning to legalise marijuana,'' the weekly science magazine said.

Dr Maristela Monteiro, a scientist with the WHO programme on substance abuse, confirmed that the analysis was dropped from the report but denied the organisation had been pressured into doing it.

``There were problems with that chapter,'' she told Reuters in a telephone interview.

``It was not a fair comparison from our point of view and from a public health perspective it was not very useful. We thought it was biased towards showing less harm from cannabis.''

Monteiro said the WHO was working with the Addiction Research Foundation (ARF) in Canada and planned to publish a book on cannabis in June.

According to New Scientist, which published a special report on marijuana on Wednesday, a leaked document about the analysis concluded that marijuana posed less of a public health threat than alcohol or cigarettes, even if people consumed the drug on the same scale as the other substances.

It also showed that while there was evidence of foetal alcohol syndrome, proof that cannabis can harm foetal development was ``far from conclusive.''

The magazine said researchers had found that marijuana smoke did not lead to blocked airways or emphysema or impact on lung function, and it was less addictive than alcohol or cigarettes.

A survey conducted by the University of Amsterdam in the Netherlands, where marijuana has been legalised since 1976, found that there was no immediate increase in use after it was decriminalised.

Although most people questioned in the survey had tried marijuana they did not continue to use it. The number of hard drug addicts in the Netherlands has not increased in a decade, the magazine added.