The Question of Cannabis

by Mary Brett
(Dr. Challoner’s Grammar School, Amersham, Bucks)

The aspect of the decriminalisation/legalisation debate that most concerns me is the risk to the health, the well-being, and the future of the very bright grammar school boys that I teach.

I do not pretend to know anything about economics, but I hardly think that drug dealers would suddenly turn into upright citizens overnight if drugs were to be legalised. They are criminals, and will surely find another dishonest way to make a living.

I am going to talk to you this morning about cannabis, marijuana, pot, hash, weed, joints etc. It’s all the same drug.

It is a dangerous myth that cannabis is harmless.

Cannabis is our commonest illegal drug and most users are totally unaware of its effects, especially on the brain.

There are now well over 15,000 scientific papers on cannabis. None of the ones I have read says it is a safe drug, and I am assured it is the same for the rest.

The facts I am about to give you are not my facts, they all come from pure scientific research.

So what are the immediate effects?

Cannabis is taken for euphoria.

But it depends on your mood – if you're feeling good, you may well feel better, but if you're down, you'll likely feel worse. You don’t always get what you expect or want.

Like alcohol it is an intoxicant, so people are not in control, and certainly should not be driving.

Cannabis has been implicated in more vehicle accidents than alcohol in some USA Surveys, although 10 times as many people use alcohol.

Alcohol is water-soluble and is cleared from the body at the rate of one unit per hour, the amount in half a pint of beer, a single whisky, or a glass of wine.

Fifty per cent of the THC (tetrahydrocannabinol), the substance in cannabis that gives the ‘high’, is still present 5or 6 days later, and 10% after a month. Traces can be detected in the hair and urine for weeks after that.

The immediate effects last at least 24 hrs. Airline pilots in a double-blind experiment on flight simulators, could not ‘land’ their planes properly after a joint taken over 24 hours previously, and had no idea there was a problem. If you have a joint today, you should not be driving tomorrow.

People sometimes suffer panic attacks and paranoia immediately after a joint - more on this later.

Maybe people won’t die from an overdose, but out of 664 marijuana-related deaths in America in 1999, in 187 of them, the only drug involved was marijuana.

However, it is the long-term effects that most concern me.

THC is fat-soluble.

It dissolves in the fatty membranes of our cells, and stays there.

A message passes along a nerve fibre in our brains as a burst of electricity, and a chemical, a neurotransmitter, jumps the gap and fits into receptor sites in the membrane of the next cell, it is all to do with shape.

The THC clogging up the membranes interferes with this transmission process. Messages simply don’t get through.

The more THC, the worse the problem.

Just one joint per week will ensure a permanent presence of THC and a constant reduction in brain energy.

Concentration, learning and memory are all badly affected.

Electroencephalographs (EEGs) of using adolescents have patterns similar to those of the learning disabled.

The learning and memory processes depend on new connections being made between nerve cells

This does not happen. The orderly release of these neurotransmitters has been disrupted.

There is now strong suggestive evidence both from animal experiments and brain scans of humans, that some of these cells die.

Brain cells are never replaced and, since they work in chains, if one dies the whole message is lost.

Dr Robert Gilkeson, an American researcher said, "It makes great people average, average people dumb, and causes more organic brain damage than any other drug of abuse except perhaps the very end stages of alcoholism".

This is permanent brain damage we're talking about – slow, subtle, insidious and cumulative.

Few children, using cannabis even occasionally, will achieve their full potential.

Mental illness

Cannabis causes far more mental illness than drugs like heroin.

An experiment in decriminalisation in Alaska was terminated in a referendum in 1991 after over 2000 people in the previous 2 years had to hospitalised and treated for cannabis psychosis, a complete mental breakdown, at enormous cost to the taxpayer.


Schizophrenia is triggered or worsened by its use.

Apathy and dropping-out are common.

Even on one or two joints a month, a cannabis personality emerges. Users become inflexible, can't plan their days properly, can't take criticism and feel misunderstood. School grades take a nosedive, and at the same time they feel lonely and miserable. They find it difficult to sustain a dialogue. Trying to talk sense to them becomes a futile exercise.


Psychological addiction (craving) is very strong and there is now evidence of physical or physiological addiction. Withdrawal symptoms have been seen, not of course so dramatic as the cold turkey of heroin withdrawal since the THC remains in the body for a long time.

Two recent papers have shown that THC occupies the same receptor sites on the brain cells as heroin. This possibly gives reasons for its pain-relieving properties. It also explains the physical addiction.

There is no foolproof cure for any type of addiction.


Cannabis smoke contains a higher percentage of some of the cancer-causing substances than tobacco.

Biopsies of the lungs of young French and American servicemen showed pre-cancerous cells not usually found in tobacco smokers till middle age.

Rare head and neck cancers are now being found in young pot smokers. The average age for these conditions in tobacco smokers is 64.

Cannabis burns at a higher temperature, the smoke is inhaled deeper and held for longer in the lungs. For full value it is smoked right down to the butt.

In cancer terms, one joint is estimated to be the equivalent of five cigarettes.

Immune System

The immune system is impaired.

Fewer white blood cells are produced, many are abnormal and can't fight infections so well.

People become more vulnerable to disease, their illness is more serious and more long- lasting.


Sperm production is decreased. This is the point at which my pupils begin to sit up and take notice.

A survey of young male pot smoking patients in Kingston Hospital, Jamaica, found 20% complaining of impotence. Thirty five per cent of them had a sperm count so low as to render them sterile.

What may worry them more however are the reports of young men developing breasts.

Babies born to cannabis using mothers are smaller, hyperactive, have behavioural and learning problems, and are 10 times more likely to develop one of the forms of leukaemia.

The production of new cells in the body – white blood cells, sperm and foetal cells, all involve the precise copying of the DNA which makes up our chromosomes. THC interferes with this process. Also cells have a certain lifespan. THC accelerates this programmed cell death which is called apoptosis.


THC also disrupts the production of the sex hormones.

Blood Pressure and Heart Rates

Blood pressure and heart rates rise to the levels of real stress – not a good idea for anyone with a heart problem.

A report in June 2001 found that the risk of a heart attack in middle-aged people increased fivefold in the hour following the smoking of a joint.

For a government that bans beef-on-the-bone, with its infinitesimal risk of causing CJD, it is incredible that they are contemplating, even for a moment, a move that will inevitably result in more people using a substance that has been proved to be harmful.

"We must err on the side of caution", a spokesman said at the time; indeed we must!

Have we learned nothing from the lawsuits brought by tobacco users?

Drugs are illegal because they are dangerous, not dangerous because they are illegal.

I want to give you two quotes from Dr Robert Dupont, founder of the National Institute of Drug Abuse in America.

"I have been apologising to the American people for the last 10 years for promoting the decriminalisation of cannabis. I made a mistake. Marijuana combines the worst effects of alcohol and tobacco and has other ill-effects that neither of these two have".


He also said, "in all of history, no young people have ever taken marijuana regularly on a mass scale. Therefore our youngsters are in effect making themselves guinea-pigs in a tragic experiment. Thus far our research clearly suggests we will see horrendous results".

What about the medical arguments?

Medicines, by law, have to be pure substances, that is, identifiable single chemicals, so that their action is predictable and controllable. Heroin and cocaine fall into that category.

Cannabis contains around 400 chemicals, when smoked this rises to 2000.

It is a little-known fact that purified THC, Nabilone, is already available on prescription but is not at all popular with doctors because of its side effects.

The BMA is currently testing more of the 60 or so purified cannabinoids unique to the cannabis plant, as potential medicines, and no one has a problem with that.

Nicotine suppresses the appetite but no one would dream of telling someone to start smoking to reduce their weight, or to chew willow bark to get their aspirin.

Pressure in the eyeball caused by glaucoma can be reduced by smoking joints, but six a day would be needed.

The patient would be permanently stoned – completely incapable of working, driving, or indeed doing anything. Alcohol would do the same job but only if they were drunk.

The ‘medical argument’ really started in America in 1979 when an American pot smoking lawyer said, "We will use the medical marijuana argument as a red herring on the road to full legalisation".

This was echoed in the early nineties by his successor, Richie Cowan who said, "Medical marijuana is our strongest suit. It is our point of leverage which will move us towards the legalisation of marijuana for personal use".

In November 1996, Proposition 200 permitted physicians in Arizona to prescribe marijuana with no limitation on the age of the patients or the disorder involved. In January 1997, 2 months later, a poll revealed that 85% of registered voters believed it should be changed and 60% wanted it repealed. Seventy per cent said it gave children the impression that drugs are OK for recreational use.

In 1998, 109 distinguished scientific researchers held a conference on medical marijuana in New York. Their papers and conclusions were published in 1999. On the last page we read, "Marijuana or THC do not qualify as safe or effective medications which aim at restoring or maintaining physiological functions of cells, organs and organisms. They have no place in a modern pharmacopoeia from which cannabis was eliminated in the first part of the century".

The latest ploy is the promotion of Hemp, Hemp is cannabis.

They claim it is needed for everything from ropes to cloth and newsprint.

In reality, it is double the price of the finest linen, paper from trees is much cheaper and hemp ropes rot and are weaker than the synthetic ones we now use.

Why? It is a very simple chemical process to extract the 0.25% THC, purify and concentrate it to a powerful 40% which they call "Chaw".


Does cannabis lead to harder drugs? It can!

Denise Kandel has conducted surveys for many years in the USA into this subject. In one, she found that 26% of pot users progressed to hard drugs compared with 1% of non-drug users, and only 4% of beer or wine drinkers.

The level of usage seems to be a major contributing factor. She reported that, of those using marijuana between 10 and 100 times in their lifetime, 51% went on to use hard drugs, from 100 to 1000 times, it rose to 79% and over 1000 times it was 90%.

In the year 2000, a large, well controlled survey from New Zealand appeared to show once and for all, that cannabis does indeed act as a gateway drug. Youngsters smoking just one joint a week were 60 times more likely to go down that road.

Of course not all of them will progress, but almost a 100% of heroin users started on pot.


I was asked to give oral evidence to the Home Affairs Select Committee in January. I was explaining to a year 9 class, (13 to 14 year olds), why I would not be seeing them that day, when one of them became very agitated. "Please Mrs Brett, please", he said, "Tell that committee that my uncle is dying. He is a heroin addict and I am not allowed to see him any more. And he started on cannabis". There is no doubt in that boy’s mind where cannabis can lead. His uncle, a favourite, is 24.


This progression has been seen whenever, and wherever laws have been relaxed.

In 1990 the Dutch Ministry of Justice admitted that Holland was the crime capital of Europe. Not everyone in Holland is happy.


Gun-related deaths have seen a 42% increase since decriminalisation. People don't realise that 80% of all violent crimes are committed under the influence of drugs including cannabis.

Health and social problems have escalated. In 1993, 20% of the so-called coffee shops in Amsterdam were closed for dealing in hard drugs. The aim of separating so called "soft" from hard drugs has not worked.

And the amount for personal possession has been reduced from 30g to 5g.

Drug dealers from all over the world have flocked to Holland, attracted by its liberal laws and penalties.

If we want a role model for a policy on drugs we need look no further than Sweden. All drugs are treated equally, they have excellent prevention programmes in place, drug taking is not considered to be normal. Drug use is very low.

The International Herald Tribune on March 31st reported a new approach to the policy on drugs in Italy.

Like Sweden, they will not distinguish between soft and hard drugs, aim for a complete rehabilitation of addicts rather than harm reduction, and promote prevention first and foremost through traditional institutions like the family and schools.


People argue it's better to have youngsters sitting around stoned and peaceful instead of being drunk and violent – NOT TRUE

A Swedish study found more suicides among pot users than those who used alcohol, amphetamines or heroin.

The manner of death was more violent – no other group jumped from high buildings or committed murder before taking their own lives.

One man killed his wife, his 4 children, then himself.

A paper last year by Dr Louise Arsenault of the Institute of Psychiatry discovered that young male pot users in Dunedin, New Zealand, were 5 times more likely to be violent than non-users.

There was an especially tragic story recently in the press. A 16 year old boy, a cannabis user, out of the blue suddenly turned very aggressive, threatening his sister and girlfriend with scissors. His father managed to subdue him and get him into hospital. After an hour they discharged him. On returning home he picked up the scissors, and, thinking he was invulnerable, plunged them into his chest in front of his helpless father. The psychiatrist at the inquest said cannabis might easily cause an acute paranoid psychosis.


All this may well be due to its strength today.

In the sixties, the average THC content was just 0.5%.

Today at 5% it is 10 times stronger.

And other specially bred varieties from Holland have THC contents from 9-27%. By distillation this can rise to 60%.

This is a very different drug from the one that fuelled the "hippy generation".

This is a strong hallucinogenic drug.


"We can do what we like with our own bodies". say the libertarians. Fine, as long as no one else is harmed in the process.

"Stoned" drivers can, and do, kill other people. Addicts need treatment, the taxpayer picks up the tab. In 1997, almost 200,000 people in America were admitted to treatment programmes for cannabis dependence, 65,000 of these were emergencies. Intoxicated workers are inefficient, unproductive and a liability, they may well become unemployable. And lets not forget passive smoking. Yes, it occurs with cannabis too!

I tell the boys:

"Drugs take control of your mind. No person can do that – no parent, no teacher, and no friend. You can't make rational decisions.

And where's the Liberty in making yourself a slave to a toxic chemical for life"?


People often compare the cannabis situation today with prohibition in the 30’s. The comparison is false. An attempt was made then to make a legal and widely used drug illegal, a drug that had been popular, could be used without damage to health, and had been around for centuries. Cannabis is currently illegal, and even when it was legal it was only ever used by a minority. Use over the centuries was always patchy. It is still used only by a minority. Regular use of cannabis today is around 8 or 9%, not the 30 or 40% who have tried it. How many have tried smoking? 90%? It only goes to show the difficulty of "putting the genie back in the bottle".

We are stuck with alcohol and tobacco. If discovered today, they would certainly be controlled drugs. We are desperately campaigning to try to stop people from smoking and abusing alcohol. Do we really want another legal drug to add to the toll of misery caused by the other two?

In fact, from a health point of view, prohibition was a spectacular success. Alcohol consumption declined, deaths from cirrhosis of the liver fell by over a third, cases of alcohol-induced psychosis plummeted. Child neglect, juvenile delinquency and alcohol- related divorces all dropped by a half.

Some of the other Arguments

"Let’s legalise it", they say, "and use the tax for the common good". There is a huge amount of cigarette and alcohol smuggling.

"We are criminalizing young people" Youngsters know the law. They are criminalizing themselves. We don’t use this argument about speeding or petty pilfering. The vast majority of people who break the speed limit never get caught, but it is no excuse to repeal the law, nor would most citizens want that to happen.

The often-quoted Lancet article, which says that moderate indulgence in cannabis has little effect on health, is vastly at odds with a later statement from the BMA in 1997. "Chronic cannabis smoking, like tobacco smoking therefore increases the risk of cardiovascular disease, bronchitis, emphysema and probably carcinomas of the lung. Adverse effects of chronic use include suppression of ovulation in women, decreased sperm count in men, sedation and anxiety".

How often do we hear that risk taking by motor-cyclists, bungee jumpers or white water rafters is on a par with taking drugs? These activities that provide a thrill by releasing our natural brain drugs and involve some degree of skill, or at least nerve, are a world away from sitting in a chair stuffing our brains with poisonous chemicals.

It was no surprise that The Police Foundation Report headed by Lady Runciman came down on the side of relaxation. The public would obviously assume that it was composed of a good cross section of opinions. They would be wrong. Only one person with any kind of scientific background was on the committee, a psychopharmacologist.

No neurologist, no biologist or toxicologist was present, the very people who know and understand how drugs work. There was not one single person who came with a previously anti-drugs stance. The libertarians were there. To name but two, Simon Jenkins the journalist who has written pro legalisation articles, and the chief executive of Lifeline, a Manchester-based charity, whose booklet on cannabis shows how a joint is rolled.

Incidentally, self appointed and self tasked, it has nothing officially to do with the police.

Whenever a committee composed of scientists reports on cannabis, the findings are always the same. Cannabis is a harmful drug and should not be legalised.

The WHO reported in 1997, The House of Lords Select Committee on Science and Technology in 1998. In the same year, Swedish scientists published a book, "The Adverse Health Consequences of Cannabis Use". The 1999 "Marijuana and Medicine" has already been mentioned. How many more publications of peer-reviewed scientific evidence do we need?

The War on Drugs has not been lost. It has never been waged.

Most of the media, the pro-legalisers and libertarians have seen to that, by their mixed messages and promotion of law relaxation. Our children are confused and bewildered.

Until we all sing from the same song sheet, nothing will change.


Drug education, according to the government’s "Tackling Drugs Together", should be all about prevention. Parents must naturally assume that this is happening. This is seldom the case. Whatever happened to the saying "Prevention is better than cure"?

The vast majority of drug educators teach harm reduction and have done for the past 15 years or so. Harm Reduction has its place when dealing with a known user, e.g. he or she can be advised to smoke heroin rather than inject thus avoiding all the blood-borne diseases.

There is no justification for advocating HR in front of a class, 90% or so of whom, have no interest in following that particular way of life.

One of the favourite phrases is "informed choice". Apart from the fact that there should be no choice, since drugs are illegal, children are not mature enough to choose. They are not miniature adults. They should never be put in a position to make critical life decisions. Harm Reduction education does not tackle drugs, it accommodates them. Adults are simply opting out and relinquishing their responsibilities.

I never say to children "Don’t do drugs" or "Just say no". I simply point out biologically what could happen to their brains and bodies, I add to that all the adverse social consequences and lost educational opportunities and they begin to see the futility of that particular lifestyle.

Prevention does work. The most spectacular success of a prevention programme was seen in America between 1979 and 1991. Parents got fed up with trendy excuses for drug taking and in collaboration with teachers, the police, customs and excise, social workers and the children themselves, fostered the idea that taking drugs was not normal and was indeed harmful. It worked.

In this period the number of drug users fell from 23 million to 14 million, a 60% reduction, use of cannabis halved, daily use dropped by 75% and cocaine use by 50%.

In 1991 they took their eye off the ball, they thought they had the problem licked, so drug use again started to increase.

Nearer home we have the highly successful prevention programmes delivered in primary schools by DARE (Drug Abuse Resistance Education), and LIFE EDUCATION CENTRES.

Children need rules and regulations. It is the only way they feel safe and secure. They need boundaries to kick against. They often use parents as an excuse when confronted with an idea they don’t want to pursue, " Mum/Dad would kill me" is a phrase I often hear. Former pupils who come back to see me are often the ones I have had to discipline most severely.

Once a year, I give a talk on cannabis to the 200 boys in our year 12, the lower 6th.

About 6 years ago a boy who had been in trouble at school over drugs listened to this talk. Three years later he phoned and asked if he could come and talk. He was doing a degree in pharmacology, having only just managed to scrape into university with C and D grades. Most of his friends didn’t make it. He wanted to write his dissertation on cannabis. I asked him what had stopped him using drugs. "You did", he said, "I could quote every word you ever said about cannabis, and gradually I realised that everything you said was true". He had also managed to stop some of his friends.

He got a first for his dissertation. I then fixed him up for a year as a technician with a friend of mine, a toxicologist. He proceeded to do an MSc and is now researching Parkinson’s disease for a PhD thesis.


Last year we conducted a survey, not yet published, among our year 10 boys, (14 to 15 year olds), as part of a research project involving 7 schools.

Regular usage in our school was low at 3%. My pupils are among my greatest supporters.

But the really interesting findings were all the factors that stopped those surveyed from using drugs, and the reasons given for using, by those who used cannabis. The results mirror a survey carried out in the United States almost 20 years ago.

Top of the list for the abstainers were worries over health (almost 90%), death (over 80%) and side effects (nearly 70%). Over 60% were deterred by parental disapproval, and the illegality of drugs stopped more of them, (nearly 60%), than a lot of people realise.


Over 60% of those who used cannabis thought it was not dangerous like the others. Over 40% thought it must be safe since there was talk of legalisation, and over 30% because it was used in medicine. Not true of course, but that is the message they are getting.

The main reasons for using were relaxation and fun. That is, of course, why drugs are usually consumed. Too many youngsters are not aware of the price they may have to pay.

Over the last few years I have met several parents who have lost children to drugs. The one who has made the biggest impact on me is a woman, a writer, now in her early seventies.

Her son started using cannabis at the age of 15 at his public school.

As so often happens he progressed through all the other drugs and spent the last years of his life in care homes and psychiatric institutions.

She never gave up on him, visiting and supporting him constantly, although on more than one occasion, when suffering from severe paranoia, he threatened her life.

Shortly before he died, at the age of 45, of a particularly pure dose of heroin, he told her he could handle any drug now, except cannabis – it made him paranoid and terrified him.


When women are pregnant they are obsessive about what they put into their bodies in case it harms their unborn child.

It must be devastating for parents to have to watch their children ruin their most precious asset - their brain - needlessly with toxic chemicals.

I’m sorry I can’t stay for lunch. As luck would have it, our annual drugs evening for parents is tonight and I have to get back to check on everything.

We have over 400 people attending, including sons if they want to come. Almost half are from year 7, our 11 year olds. That illustrates the depth of concern felt by our parents.

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