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Prevention: our next generation

The greatest concern about cannabis is perhaps that its dangers are too-often downplayed. Research findings are ignored, misinterpreted and denied.

Article 33 of the Convention on the Rights of the Child says that “States Parties shall take all appropriate measures, including legislative, administrative, social and educational measures, to protect children from the illicit use of narcotic drugs and psychotropic substances as defined in the relevant international treaties”.

I was a biology teacher in a school for boys for over 30 years and introduced health education. Children always want and need explanations for everything, so I decided to show them exactly how drugs can affect the body, particularly brain cells, using simple scientific diagrams and reasoning. My talks would be factual, non-patronising and regularly updated. Watching the faces of children change as understanding slowly dawns as to how drugs work is very rewarding.

My greatest concern was then, and is now, cannabis. It’s the most commonly used illegal drug – 2-3million users in the UK, 3.6million daily users in the US – and its dangers are constantly downplayed. Up-to-date research findings are ignored, disputed and challenged by people, some of whom are users. Most don’t read all or even any of the literature. Some cherry-pick the occasional paper to suit their purpose, constantly quote it and argue that it proves their point despite many others that find otherwise.

The normalisation of drug use is indefensible. Only about 3% of the adult population in the UK regularly use drugs so about 97 % do not; in the US, 1.1% of the population are daily users. Drug use is clearly not the norm and this must be constantly emphasised.

How does cannabis affect children’s bodies?

The first thing is to look at the brain cells. Cannabis receptor sites (C1) are in many areas of the brain and (C2) in other cells of the body. So its effects are many, widespread and varied. Messages pass along nerve fibres as tiny electrical impulses and cross the gap – the synapse – between nerve cells as chemicals called neurotransmitters. These are the brain’s natural drugs and there are dozens of them. Each neurotransmitter molecule has a specific shape that fits into its own receptor site on the next cell, as a key fits a lock. Mind-altering drugs operate at these synapses. They can mimic the neurotransmitters by shape, increase the rate at which they are released, block them or prevent them being recycled.

The substance that gives the “high”, THC – tetrahydrocannabinol – mimics anandamide (Sanscrit for ‘bliss’), a neurotransmitter. Receptor sites for anandamide, and so THC, are in many areas of the brain and other cells of the body. Unlike most other common drugs, THC is fat-soluble so persists in the fatty membranes of brain cells: 50% will be there after a week and 10% a month later. Traces are found in hair and urine for weeks after that. This “clogging up” of the cells by THC interferes with the transmission of other neurotransmitters so functioning of the whole brain is impaired.

Potency has increased since the 19602/1970s.

In the 1960s/1970s, the average THC content of herbal cannabis was about 1-2%. In the UK’s last potency report in 2008, the THC content of ‘skunk’ averaged 16.2% up to 46%. 80% of the cannabis seized, mostly grown here in “factories” and “farms” was skunk. The rest was hash (resin), with about 4-6% THC. The Dutch are considering banning the sale of skunk with a THC content of 15% or more. They equate it with the UK’s class A drugs, cocaine and heroin.

“Old-fashioned” herbal cannabis had about equal amounts of THC and an anti-psychotic substance CBD (cannabidiol). CBD used to counteract some of the psychotic effects of THC, but it is almost absent (0.1%) from skunk.

Addiction, substance dependence.

Most drugs that can be abused – heroin, cocaine, alcohol, nicotine and cannabis – increase the amount of dopamine, the “pleasure” neuro-transmitter in the brain. It’s also increased by eating, listening to music, exercise etc. But two other substances are produced. One reduces the brain’s natural production of dopamine so more is needed to get the same effect; this creates tolerance to a drug. The other creates new connections and receptor sites, making the brain more open to the drug. These cravings persist for a long time and come back even years after a person has stopped. I tell children that they can increase the release of dopamine naturally with the brain in control, for example by jogging, rather than stuffing it with random amounts of chemicals which then take charge with unknown and sometimes tragic outcomes.

Physical dependence happens when cannabis replaces anandamide. Production of anandamide drops; it’s not needed. If a person then stops taking cannabis, the receptor sites are empty. They have to be filled otherwise withdrawal sets in – irritability, sleeplessness, anxiety, depression, sometimes even violence. It takes time for the anandamide to resume production. Withdrawal from cannabis is not as dramatic as drugs like heroin since THC persists in cells for a long time.

Of everyone who tries cannabis, 10% will become addicted. In teens this rises to 1 in 6. A record number of children are being treated for cannabis addiction. 13,581 youngsters under 18 were treated in 2013/4 – a 50% rise in 7 years including 200 aged 12 or under. Treatment averaged 150 days and involved counselling and support. Rehab specialists told us that cannabis addiction is the most challenging to treat.

What does this mean for children’s health?

Cannabis can cause psychosis. We have seen this from long-term studies from birth, and the fact that cannabis increases dopamine. The brains of people with schizophrenia and psychosis have excess dopamine. The first paper linking cannabis and psychosis was published in 1845. It’s simply a matter of how users they take at a time – too much and they can suffer a psychotic episode. Skunk users are almost 7 times more likely than hash users to suffer. This was work done by Professor Sir Robin Murray and his team at London’s Institute of Psychiatry in 2009. He was also involved in the work on CBD.

Some people have a genetic vulnerability to schizophrenia. In general, cannabis users are at least 2-3 times more likely to develop this life-long condition than non-users.
Scans of users’ brains show a decrease in volume, which might be permanent, in parts of the brain’s grey matter (cell bodies), hippocampus (learning), thalamus (receives and passes on messages) and amygdala (emotions). A decrease in white matter has been seen in the cerebellum.

Violence and aggression are usually linked with alcohol, with cannabis perceived as a ‘peaceful’ drug. But a New Zealand study found young male users almost 4 times more likely to be violent than non-users – the risk for alcohol was about 3. Violence is thought to be linked with psychosis or withdrawal. A Swedish study found more suicides among cannabis users than those who used amphetamines, alcohol or heroin – and the manner of death was more violent. Cannabis smokers are almost 20 times more likely to commit suicide by jumping than a non-user. Some high-profile homicides have also been linked to cannabis use.

Less dramatic but harming more young people are the effects on personality and academic performance. Because THC persists in brain cells, it interferes with other neurotransmitters. New connections are made in learning and memory processes. During adolescence, this is particularly important as there is normally a growth spurt of these new nerve branches but their formation is impaired. Just one joint a week or even a month will ensure the permanent presence of the drug.

Cannabis users can become anxious or apathetic. The risk of deep depression is doubled even in weekly users and can lead to suicides. In 2009, it was found that serotonin, the natural ‘happiness’ neurotransmitter, is reduced. Children’s brains are undeveloped. They will not be fully mature till their 20s. The younger a person starts using cannabis, the worse the damage.

School grades fall, As and Bs become Cs and Ds. An average grade D student is 4 times more likely to have used cannabis than an average grade A and some miss out on university places. A teenage user continuing to smoke will lose an average of 8 IQ points. The IQ of non-users rises. A cannabis personality develops, users have fixed opinions and fixed answers. They find it hard to find words, can’t take criticism, and can’t plan their day. Trying to talk to them is futile. They and their families suffer from their violent mood swings, houses get trashed, family members get injured. At the same time, they are lonely, miserable and feel misunderstood. They are twice as likely to drop out of education. An Australian report commented that, while alcohol and cannabis both carry health risks, the overwhelming evidence is that cannabis is the drug for life’s future losers.

“You have one real chance at education,” I tell pupils. “Few children using cannabis, even occasionally, will achieve their full potential.”

As with alcohol, cannabis users shouldn’t drive. Over 24 hours after taking THC, airline pilots trying to “land” on flight simulators made errors butthought they were fine. An average joint (20mg) is thought to have the same effect as being just over the drink-drive limit. Combining alcohol and cannabis is 16 times more dangerous than either drug alone.

Cannabis smoke contains more carcinogens than tobacco. The smoke is inhaled deeper, held in the lungs for longer, and smoked down to the butt. About 3-4 times as much tar is deposited in the airways of the lungs. One joint in cancer terms equals 4-5 cigarettes. Rare head and neck cancers occur in young people, previously seen only in much older tobacco users. Collapsed lungs, lungs riddled by holes and even young people needing transplants are documented. Bronchitis and emphysema can result.

The DNA in any new cells being formed in a body will be damaged by THC. THC speeds up the programmed cell death (apoptosis) of white blood cells, our defence cells. Fewer are made, some are abnormal – and protection against infection weakens. People are more vulnerable to disease, their illness worse and longer.

Exposure to second-hand cannabis smoke causes mild intoxication, minor problems with memory and coordination and, in some cases, positive tests for the drug in urinalysis. Some participants did not pass the equivalent of a workplace drug test. Note the implications for driving.

A Christchurch study from birth concluded that the greatest single factor in progressing to other drugs is the use of cannabis. And research on almost 30,000 French adolescents found occasional users 21 times more likely to proceed to other drugs, daily users 124 times!

THC shortens the life span of sperm cells, too. Young men suffer infertility, even impotence.

The birth weight of babies born to cannabis-using mothers is lower and they can have problems with behaviour, brain function (particularly problem-solving, learning, memory and planning) as they grow. They are more likely to develop one of the commonest childhood cancers, neuroblastoma, or one form of leukaemia, and to use cannabis at adolescence. Babies often have mild withdrawal symptoms.

There is a rise in blood pressure and heart rate. Heart attacks and strokes have been recorded, with paralysis. Boys who smoke cannabis before puberty can stunt their growth by over 4 inches.

Apart from driving, the combination of cannabis and alcohol is all too dangerous and common. If a person drinks too much, they can overdose and die. But often they are sick and get rid of some. If they use cannabis as well, the vomiting reflex is inhibited. Tobacco, alcohol and cannabis can all lead to the taking of other drugs. If a person starts to smoke cigarettes, the technique of smoking is learned. A MORI poll found that 50% of smokers had tried an illegal drug but only 2% of non-smokers.

Because cannabis stays in the body for weeks, tests will be positive even if a joint was taken a month ago. More employers test future employees and their workers. Visas for countries like the US will not be issued to anyone with a cannabis conviction.

I’ve surveyed the international evidence base for the efficacy of drug education. To learn what truly works – and it’s not harm ‘minimisation’ – click here for more information.