Cannabis and its effects

Mary Brett, Former Head of Health Education, Dr Challoner’s Grammar School, Amersham, Bucks. EURAD UK spokesperson

Cannabis, marijuana, joints, weed, pot, hash is our commonest illegal drug, currently used in Britain by around 3.2 million people. Most of them are totally unaware of its damaging effects, especially on the brain. There are now in excess of 15,000 scientific papers on cannabis. None of the ones I have read say it is a safe drug, and I am assured it is the same for the rest.

We need to know how this damage is caused, and I will start with the cells of the brain. Messages pass along the nerve fibres as minute electrical impulses and cross the gap, the synapse, between nerve cells in the form of chemicals called neurotransmitters. These are the brain’s natural drugs and there are dozens of them. Each neurotransmitter molecule has a particular shape that fits into its own receptor site on the next cell, as a key fits into a lock.

The mind-altering drugs that people take operate at these synapses. They either mimic the neurotransmitter by shape, increase the rate at which they are released, block them or prevent them from being re-absorbed. In other words they take control of the brain!

The psychoactive ingredient in cannabis is a substance called Tetrahydrocannabinol, THC for short. It mimics a neurotransmitter called anandamide, from the Sanskrit word, ananda, which means bliss. Receptor sites for anadamide, and therefore THC, exist in many regions of the brain and on other cells of the body. So the actions of cannabis are many and varied.

In the brain, CB1 receptors in the sensory areas are affected so sound and colour perception are distorted. Muscle coordination and psychomotor skills like driving are impaired in the motor areas, judgement, reasoning and logical thought are also affected. The hippocampus is where memory and the appreciation of time and space are situated. There are other areas with receptors, but the lack of them in the brain stem which controls automatic functions like respiration, is thought to explain the absence of overdosing. In the rest of the body the receptors are called CB2 receptors.

But it is in the limbic region of the brain, a circular area in the centre, which suffers the greatest impact from cannabis. This is the seat of the emotions, and its activity determines our moods, whether we are happy or sad, anxious or peaceful. Anxiety, depression, panic attacks and even paranoia can be triggered if it is disturbed. It also houses the “pleasure” or “reward” system. Many drugs affect this area to give a “high”, e.g. cocaine, ecstasy, amphetamines, alcohol and nicotine. Cannabis is no exception. The reason people give for taking cannabis is to get a “high” or a feeling of euphoria.

All these drugs release the neurotransmitter, dopamine. However, THC acts on the CB1 receptors more strongly and for a longer time than anandamide so the effects are prolonged and enhanced. THC has to be entirely eliminated from the body whereas anandamide is quickly broken down and recycled.

One experience of a “high” leads to another and another. Tolerance develops, receptors need more stimulation and more are produced Dependence occurs, both psychological and physical. Withdrawal symptoms have been seen, shaking, insomnia, irritability, anxiety and aggression. Not so dramatic as the “cold turkey” of heroin withdrawal since the fat-soluble cannabis remains so long in the body. Fifty per cent of the THC from a joint will still be there five to six days later and ten per cent after a month. Compare this with water-soluble alcohol which disappears at the rate of one unit an hour.

Out of the six million drug addicts in the United States, approximately sixty per cent are dependent on cannabis, and more youngsters are being treated there for marijuana dependence than for alcohol. An Australian researcher, Professor Wayne Hall, estimates that of those who ever try cannabis, ten per cent will become addicted, roughly the same number as for alcohol.

There is no foolproof cure for any type of addiction.

The effects on the brain are not limited to addiction. People don’t always get the desired euphoria they are seeking. The most common adverse effect is anxiety or even panic. Symptoms can range from restlessness to loss of control to paranoia and fears of impending death. Although these are usually short-lived, occasionally they persist for several weeks. Numerous studies especially in the last few years have linked an increased risk of major depression with cannabis use. The greater the frequency of use the higher the risks. Daily use was 3.4 to 6.4 times more likely to result in a depressive illness, weekly use doubled the risk factor.

Arguably the most worrying consequence of cannabis use is the development of mental illness. There has been a 40% increase in the admission of cannabis users to hospitals for mental illness since down-classification was suggested. Scientific papers written in the sixties and seventies warned of this and recently there has been a flood of research. Professor Robin Murray who has done so much to publicize the problem, talking about public health messages said, “Action is needed to avoid a further burden on our already over-stretched mental health services”. The government promised us an information campaign on cannabis and mental illness. What’s happened to it?

I have already mentioned that cannabis increases the release of the neurotransmitter, dopamine. Schizophrenics have an excess of dopamine in the brain. Cannabis-induced psychosis has long been recognized and IS curable given time if the person abstains, but schizophrenia is a lifetime condition. Recently it has been found that 1 in 4 of us carries a faulty gene involved in dopamine transmission. If a child inherits 2 copies of the gene AND uses cannabis, the chances of developing schizophrenia rise from 3%, the normal incidence in the population to 15%. Scans of the brains of adolescent schizophrenics have abnormalities similar to those of daily cannabis users.

Swedish studies which followed the progress of over 50,000 conscripts, aged eighteen to twenty-five, over fifteen years, discovered that the risk of developing schizophrenia was increased by a factor of six for those who had used cannabis more than fifty times. This was when the average concentration of THC was much lower than it is today. The commonest form of cannabis used to be resin with a THC content of 4 to 6%. But now Skunk and Netherweed, selectively bred varieties of herbal cannabis from Holland can have THC contents of anything from 9% to 27%. More than 60% of cannabis used in the UK today is of this type and most is home-grown. This is a very different drug from the one that fuelled the “hippy” generation.

I talked to a roomful of parents all of whom had children psychotic or schizophrenic due to cannabis. It was one of the most harrowing evenings I have ever spent. So many ruined lives, so much wasted talent, so many devastated families.

Many pro-legalisers say that children are better off stoned and peaceful than drunk and violent. This is not true. Violence has been associated with the psychosis caused by cannabis use and also during withdrawal from the drug. One study from New Zealand discovered that young men were five times more likely to be violent than non-users, the increased risk for alcohol was three. In a Swedish investigation into suicides, users of alcohol, amphetamines and heroin were compared with marijuana users. More cases occurred in cannabis users than in any other group and the methods used were more violent. No other group jumped from high buildings or murdered others before taking their own lives. There have been several tragic tales in the press in the last year or so, of young people committing suicide after taking cannabis. Maybe people don’t die of an overdose, a common cry of the pro-legalisers, but in 1999, in the United States, out of 664 marijuana-related deaths, in 187 of them, the only drug involved was marijuana.

High densities of CB1 receptors in the cortex and hippocampus cause concentration and the learning and memory processes to be badly impaired. In one way or another the long-term presence of THC interferes with ALL the other dozens of neurotransmitters. In the learning process, the brain cells make new connections. THC interferes with the release of the neurotransmitters responsible for making these connections. Even on one or two joints a month, a cannabis personality develops. Users become inflexible, can’t plan their day properly, their problem-solving skills deteriorate, they can’t take criticism and they feel misunderstood. School grades take a nosedive and pupils often miss out on their chosen university places. They are more likely to end up with C and D grades when they should be getting As and Bs. I know I’ve seen it happen. At the same time they are lonely and miserable. Few children, using cannabis even occasionally, will achieve their full potential.

A few years ago, a former pupil came to see me. He was in his last year of a degree in pharmacology and wanted to do his dissertation on cannabis. He was a very bright boy but having been a user of cannabis while at school, he had only just managed to “scrape” into university with very poor grades. Most of his friends didn’t make it. “What stopped you”, I asked. He looked surprised. “ You did”, he said, “I could quote every word you ever said about cannabis, and all of it came true”. He also managed to stop some of his friends. He got a first for his dissertation, spent a year with a friend of mine, a toxicologist as a technician, did an MSc in neurology, and has now completed a PhD researching brain diseases.

Because CB1 receptors are in the motor area of the cortex, psychomotor performance and muscle control are affected. People should not drive. Airline pilots, on flight simulators could not land their planes properly even up to and beyond twenty-four hours after a joint and had no idea that anything was amiss. If you have a joint today, you should not be driving tomorrow. Cannabis has been implicated in more vehicle accidents in some American surveys than alcohol, although ten times as many people drink.

CB2 receptors are found in the cells of our immune system and THC disrupts the copying of DNA into new cells being made in the body. Fewer white blood cells, our defence cells, are produced and some are abnormal. As a result, people are more likely to fall ill, their sickness will be prolonged and be more severe.

The heart also contains CB2 receptors. The heart rate is increased and blood pressure rises. Heart attacks were reported in young men, heavy users in their twenties, that could not be explained away except by their use of cannabis. And two teenagers died after “bingeing” on cannabis, another was left paralysed. They all had suffered strokes.

Cannabis smoke contains more of some of the carcinogens found in tobacco smoke and deposits three to four times as much tar in the airways. Lung biopsies of young French and American soldiers found pre-cancerous cells, not usually found till middle age in tobacco users. As well as lung cancer, rare head and neck cancers are now being seen in young cannabis users, not found in tobacco smokers till the average age of sixty-four. Cannabis burns at a higher temperature, the smoke is inhaled deeper and held longer in the lungs. One joint in cancer terms is thought to be the equivalent of five cigarettes. Collapsed lungs, lungs shot through with holes and young people needing transplants are all part of the sorry saga.

Now I will address the effects on reproduction.

Sperm have very high concentrations of CB2 receptors, and the female uterus is rich in anandamides, so it is hardly surprising that cannabis can have significant effects on the reproductive process.

There was a rash of papers on cannabis and reproduction in the late seventies and early eighties, when the % 0f THC on average was much lower. Production of testosterone and sperm in mice was seen to decrease and some sperm were abnormal. Human sperm have consistently been seen to be lower in numbers, and with decreased mobility. Surveys on young male pot-smoking patients, twenty years ago in Kingston Hospital, Jamaica, found twenty per cent complaining of impotence and thirty-five per cent with a sperm count so low, it would render them sterile.

Ovulation in mice was inhibited and in pregnant rodents, in some cases whole litters were reabsorbed, abortions and foetal deaths occurred in others. In rhesus monkeys, stillbirths were recorded. Some of their viable offspring, apparently normal, had some abnormal cells. In rabbits, no major malformations were found but there was an increase in minor ones. The offspring of treated male mice had reduced fertility and some abnormal chromosomes in the testes. Two of these progeny sired litters of pups with severe congenital malformations.

Some of this older research has been criticized for various reasons but in 1994, the eminent cannabis researcher, Australian Professor Wayne Hall said, “It would be unwise to exclude cannabis as a cause of malformations until larger studies incorporating better controls have been carried out”.

One thing that is consistent in the research of today and twenty years ago is the reduction in weight and length of the baby, the equivalent of smoking ten to fifteen cigarettes a day. These babies also had mild symptoms of withdrawal. Three studies in the early nineties linked cannabis use to a ten-fold increase in cases of one form of leukaemia, and increases in two other forms of childhood cancer. More recently there has been another flood of research papers, some confirming the earlier research.

In 2003 it was again found that fewer sperm were produced and they were moving too soon and too fast, probably resulting in “burnout” before they could reach the egg. This could be a cause of infertility. Anandamide controls implantation of the embryo. Too high a level prevents implantation so cannabis smoking would do the same as the THC replaces the anandamide.

This year (2006) the risks of ectopic pregnancies and miscarriage were highlighted in women smoking cannabis in the early stages of pregnancy, embryos of mice had more cell abnormalities and they failed to travel to the uterus. In an investigation into IVF and GIFT, cannabis-using women produced fewer eggs and the babies were smaller. In December, 2002, one in every eight babies born in The Princess Royal Maternity Hospital in Glasgow, had been exposed to cannabis before birth. Seventy-five per cent of babies exposed to drugs in the womb have medical problems later in life compared to twenty-seven per cent who are not exposed.

The progress of babies born to cannabis-using mothers is being followed in a long-running investigation in Ottawa by Peter Fried and others:

Initial signs of deficiency in neurological behaviour seemed to disappear by the end of the first year and may have been due to withdrawal. By four, memory and verbal abilities were deficient, again these appeared to go, but by five to six they had difficulty in maintaining attention. From then till the age of nine, several deficiencies in cognitive functioning were detected, especially their executive functioning, the ability to plan things and solve problems, exactly the same difficulties experienced by adults. By the age of twelve, this impairment of executive functioning was still apparent. The parents reported above average problems with behaviour, decreased attention and more impulsiveness. Fried has also warned of delay in the maturing of the visual system. These children are now 16 and the problems remain. They are more than twice as likely to use marijuana when they reach adolescence.

Deficiences are not really apparent till the age of four. This is when children start using their “executive functions.” Fried also warns that today’s stronger varieties will almost certainly make things worse. Other researchers have come up with supporting evidence. In two studies of three year-olds, one found the results of intelligence tests to be below normal, another, investigating sleep patterns, found more problems, more arousals and low sleep efficiency. Teachers have complained of delinquent behaviour at the age of 6 and symptoms of ADHD have been reported.

In 2003 Italians at Cagliari University reported the offspring of rats to be significantly more hyperactive in infancy and they scored lower on learning tests throughout their lives. Similar results were seen by another Italian team in the same year. Rats are useful experimental subjects as they don’t have confounding factors like smoking, class differences or delinquent peers.

Cells have a lifespan. In 2002 it was discovered that THC induces apoptosis, programmed cell death in fast-dividing cells in the body, sperm –producing cells and cells of the immune system. The DNA of the cells is irreversibly damaged. This would seem to explain at least some of the embryo damage and retardation of foetal development seen in pregnant smokers.

The difficulty in dealing with all cannabis research, including cannabis and pregnancy, is of course the illegality of it. The stigma associated with this discourages honest reporting. If many users are classed as non-users, then the differences between the groups will not show up. The biggest problem is numbers. Thankfully not many pregnant women are heavy users of cannabis but large numbers are needed for the results to be statistically significant.

I would like now, to address a few of the controversies surrounding cannabis.

The first is the medical argument. In 1979, a pot-using American lawyer, Keith Stroup, said, “We will use the medical marijuana argument as a red herring to give pot a good name”. In the early nineties, Richie Cowan his successor at NORML, the National Organization for the Reform of the Marijuana Laws, echoed this by saying, “ Medical marijuana is our strongest suit. It is our point of leverage which will move us toward the legalization of marijuana for personal use”. This campaign is still ongoing.

There may well be some ingredients in the cannabis plant that may prove beneficial in medicine. But that is the point – the ingredients. Medicines, by law, have to be pure single chemicals so that their actions are predictable and controllable. THC is already available as Nabilone in Britain and Marinol in the USA. The pro-legalisers don’t tell you this – they want their joints. These prescription drugs however are unpopular with doctors because of their side effects.

Currently the BMA is clinically testing some of the other purified cannabinoids, there are around sixty of them in the plant, and no one should have a problem with this. It is estimated that people suffering from glaucoma would need six joints a day to maintain reduced pressure in the eyeball. Permanently stoned, they would hardly be useful members of the community! Nicotine suppresses the appetite. It’s like saying to someone, “ Take up smoking to get your weight down”. Any GP, giving this advice would be severely censured.

Another controversy is the gateway theory. “Does cannabis lead on to other drugs”? Tobacco alcohol and cannabis all make the use of other drugs more likely. Many studies have confirmed that there IS a progression for some people. The younger they start, the further they progress and the heavier the use, the greater the risk. Studies from Australia and New Zealand, always controlled for confounding factors, have found that weekly users are sixty times more likely to progress, and the trend is confirmed by research on twins. Of course not everyone will go down this route, but almost one hundred per cent of heroin users started on cannabis.

Theories include : exposure to dealers, peer-group pressure, personality or background factors, curiosity or an actual change in brain chemistry. This last explanation has been gaining ground lately. Cannabis would seem to “prime” the brain for the use of other drugs.

Now I want to tell you, at least in my view, why we are in such a mess with drugs.

Parents must naturally assume that drug education in schools strongly discourages children from starting to use drugs. They could not be more wrong! The great majority of drug educators teach harm reduction and have done so for the past fifteen years or so. Harm reduction has its legitimate place when dealing with known users to try to limit the damage with the aim of getting them to stop. They can be encouraged to “chase the dragon”, inhale the fumes from heroin rather than inject it and so avoid all the blood-borne diseases like AIDS and hepatitis. It has no place in the classroom where around ninety per cent of pupils have no intention of following that way of life. But it is government policy and is seen in all the official guidelines on drug education sent to schools. One of the favourite phrases of harm reductionists is “informed choice”. There should be no choice – drugs are illegal. Surely teachers of all people should be seen to be upholding the law. And also, children are currently not being properly informed, especially about cannabis, to make a choice. Harm reductionists consistently play down the effects of cannabis, or even lie. They don’t “tackle” drugs, they accommodate them. Adults are opting out and abrogating their responsibilities. The first duty of parents, and indeed all adults, is the protection of vulnerable youngsters from anything that puts them in danger. We don’t let our offspring cross a busy road till they are old enough, or run towards a fire and burn themselves, why abandon them to drugs? Nor do we let them choose to break the law in other ways, e.g. speeding or petty pilfering.

It’s not surprising that drug use is rising in this climate of acceptance. Preventing kids from starting to use drugs is, after all not the aim of harm reduction.

Children need rules and regulations. The only way they feel safe and secure is when they have boundaries to kick against. They often use their parents as an excuse when they want to opt out. “ Dad would kill me”, is a phrase I frequently overhear. They have no time for teachers who can’t control a class.

I never say, “Don’t do drugs or just say no”. I simply point out, in biological terms, what can happen to their brains and bodies. I add to that all the social, family, emotional, educational and employment consequences of that way of life and they begin to appreciate its futility of it. Prevention does work. The most spectacular success of a prevention programme was seen in the United States between 1979 and 1991. This was the famous “Just say no” campaign. It did work in spite of what the pro-legalisers say. Parents got fed up with the trendy excuses for drug taking and collaborated with teachers, the police, social and youth workers, customs and excise and the children themselves, to foster the idea that drug-taking is not normal and was indeed harmful, and it worked! The number of drug users fell from twenty-three to fourteen million, a reduction of sixty per cent, use of cannabis and cocaine halved, daily cannabis taking fell by seventy-five per cent.

In surveys at the time, the most common reason for abstaining from, or quitting cannabis use was concerns over health. Parental disapproval played a large part, as did the law.

In 1991, they thought they had licked the problem and took their eyes off the ball. Inevitably usage once again rose, but now, under the new drug tsar John Walters, once again it is on the decline, year after year. In 2002, current marijuana use among 12 to 17 year olds was 8.2%. In 2005 it had dropped to 6.8%. Ours is rising.

The Swedes have always had excellent prevention programmes in place, and their whole culture is anti-drug. Sweden has a very low level of drug use.

Schools are bombarded with harm reduction literature, some of it is unbelievable and quite shocking. Here are some examples of the Manchester-based charity, Lifeline’s approach. In their leaflet on cannabis they say, “The single biggest danger with cannabis is still the risk of getting caught with it by the police”. The last line reads, “A lot of people who are now both parents and grandparents smoked cannabis when they were younger……….” Other street-wise pamphlets are full of graphic pictures of sex and four-letter words.

You can download a free 24-page booklet on how to inject anabolic steroids.

When I gave evidence to the Home Affairs Select Committee on cannabis, I showed them some of this stuff. They were, to give them their due, collectively shocked, and initiated an inquiry into their funding, which incidentally came from central government and health authorities. The Sunday Telegraph at that time, took up the story. Their funding was cut! Unfortunately they are still in business.

Drugscope, currently advises the government on all aspects of drugs. They consistently deny that cannabis is physically addictive and fail to mention some of its effects, while playing down the significance of others. They don’t want anyone arrested for the possession of small quantities of drugs – any drugs! Needless to say, they enthusiastically endorsed David Blunkett’s ill-advised proposal to down grade cannabis. They also called for the reclassification of ecstasy and LSD as well as cannabis. “ There is no conclusive proof that cannabis causes psychosis”, they say. We don’t have conclusive proof that tobacco causes lung cancer and never will have. You are not allowed to paint the lungs of someone with tar to see what happens. Admissions to hospital for mental illness in cannabis users has increased by 40% since down-classification was suggested.

FRANK is the official government website to inform children and their parents about drugs. This is just one of their “gems” of advice (“Give the first drug plenty of time to kick in or wear off before taking another one”).

Connexions, an organization now charged by the government to give advice to schools on such matters as careers, counselling and drugs, sent drug leaflets to my school. They were written by “The Clued-up Posse”, a group of kids from Fife. There was virtually no information on the dangers of pot, but masses on risk reduction. My sixth form thought they were patronizing, useless and positively encouraging of drug use. They also pointed out that the leaflet mimics a Rizla packet. I managed to get it banned again with the help of the Sunday Telegraph.

Then we have all the blatant promotion of cannabis with logos on T-shirts, jackets and bags and on the front of magazines like Ministry. We have pop-stars and even MPs openly boasting about using cannabis, and songs which glorify drugs. Pro-legalisation articles abound in the national press, and information about where to get cannabis seeds and paraphernalia is freely available in magazines and on the web. Propaganda like this makes my job a never-ending uphill struggle.

I want to finish with two quotes.

Dr Robert Dupont, founder of the National Institute for Drug Abuse in The United States said, “I have been apologizing to the American people for the last ten years for promoting the decriminalization 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”.

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

Thank you, for listening.

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