Why Cannabis Must be Reclassified

By Mary Brett, BSc.

Today’s cannabis is much stronger
In 1971 drugs were classified in the UK,and cannabis was placed into the B category. Since then it has changed out of all recognition. The THC (tetrahydrocannabinol, the psychoactive ingredient) content at that time was under 1%. This rose in 2002 to more than 7%. Specially cultivated varieties like skunk and nederweed can have THC contents of more than 30%.

Even more alarming is the fact that the class A cannabis oils with up to 60% THC are now also downgraded to class C. Although rare in Britain, these powerful mind bending drugs should stay where they were, in their proper place, alongside cocaine and heroin.

Persistence in the cells
THC is rapidly absorbed into the blood and then sequestered into fatty tissue in the body, especially the cell membranes of the brain. Release of THC back into the blood is very slow. Fifty per cent will still be there after a week and 10% a month later. The prolonged presence of the drug in our brain cells, results in the disruption and impairment of the chemical communication system, the neurotransmitters between the cells, for some considerable time.

Dependence and addiction
Because THC mimics and so replaces one of the neurotransmitters, anandamide, it has its own receptor sites. These occur in many different areas of the brain so many systems are affected. These include concentration, memory, learning, motor skills, judgment, reasoning, planning, logical thoughts, reward, pain, sound and colour perception. Tolerance and physical addiction occur and withdrawal symptoms are common when use of the drug ceases, though not so severe as the “cold turkey” of heroin withdrawal due to its persistence in the body.7 The earlier the child starts to use cannabis, the greater the escalation of use. In September 2002, out of 6 million drug addicts in the USA, two thirds were cannabis dependent. More were being treated for cannabis than for alcohol addiction. Psychological addiction has been recognized for many years and is very difficult to treat.

Driving and flying hazards
Psycho-motor skills are affected so cannabis intoxication is a driving hazard In some American studies, cannabis has been implicated as many times as alcohol in accidents, although 10 times as many people drink. In Norway, 56% of drug-impaired drivers who tested negative for alcohol tested positive for THC.12 It has been estimated that in 2001, out of 4 million high school seniors in the US, approximately one sixth admitted to driving under the influence of cannabis. Of these, 38,000 reported crashing as a result. Alcohol was blamed for 46,000 accidents. Airline pilots on flight simulators could not land their planes properly even 24 hours after a joint and had no idea they had a problem. Someone having a joint today should not be driving tomorrow.

Psychiatric risks/schizophrenia/psychosis
Mental illness and cannabis have been linked for a long time15 but 3 papers in the BMJ in November 2002 brought the subject sharply into focus.16 Studies from New Zealand, Australia and Sweden found strong links with a variety of mental disorders including schizophrenia, psychosis, depression and anxiety. A separate Dutch study noted that 50% of psychiatric cases were due to cannabis. Professor Robin Murray of The Institute of Psychiatry has been widely quoted recently in the press, saying that cannabis is the “number one problem facing mental health services in inner cities”. A colleague, Dr Paddy Powers said that cannabis is a factor in 70 to 80% of all psychosis cases. Over 2000 cases of cannabis psychosis in a 2-year period caused an experiment in decriminalization in Alaska to be terminated by public referendum in 1991.

THC increases the amount of the neurotransmitter dopamine released in the brain. The psychiatric symptoms of schizophrenia are mediated by dopamine. This may prove to be the link. A Swedish scientist, Jan Ramstrom, said in 1989, “Cannabis is one of the most psychopathogenic narcotic preparations. It is worth mentioning that the opiates (heroin etc), apart from the development of dependence itself, produce far fewer toxically precipitated psychiatric complications than do cannabis preparations”

One of the cries of the liberalisers of this drug is, “Better for kids to sit around stoned and peaceful rather than be drunk and violent”. Not so! A New Zealand paper in 2002 showed young male users to be 5 times more likely to be violent than their non-using peers.

Maybe you can’t overdose on cannabis; tobacco smokers don’t overdose either; in US records for 1999, of 664 marijuana related deaths, 187 of them involved only marijuana. Mentions of marijuana use in emergency room visits has risen in the United States by 176% since 1994, surpassing those of heroin. 110,000 such visits were recorded in 2001.

Personality changes
Even on one joint a month, a “cannabis personality” develops within a year or so. Users become inflexible, can’t plan their days properly, can’t take criticism or criticise themselves. At the same time they feel lonely and misunderstood. Trying to talk sense to them becomes a futile exercise.26 They are more likely to drop out of school, steal, become violent, run away from home or contemplate suicide.27 Adolescents with their immature brains are particularly vulnerable to mind-altering drugs. Personal and emotional development can be severely compromised.28

Cognitive impairment/school performance
Teachers will tell you that school performance begins to decline with those using cannabis. An American paper showed that youths with an average grade D or below, were more than 4 times as likely to have used cannabis in the past year as those with an average grade A. Australian researcher, Dr Nadia Solowij, said, “Use more often than twice a week for even a short period of time, or use for 5 years or more at a level of even once a month, may each lead to a compromised ability to function to their full mental capacity, and could possibly result in lasting impairments”.

A study of municipal workers found those using cannabis on or off the job reported more “withdrawal behaviours”, leaving work without permission, daydreaming, shirking tasks and spending work time on personal matters. All practices that adversely affect productivity and morale, not only for the users but also their colleagues.

Lung disease – emphysema/ bronchitis/cancer
Cannabis smoke contains between 50 and 70% more of the carcinogens found in unfiltered tobacco smoke.32 The amount of tar and levels of carbon monoxide absorbed are 3 to 5 times more than for the same amount of tobacco.33 Pre-cancerous changes have been seen in the airways of 20 to 30 year olds,34 and rare head and neck cancers, formerly only seen in older tobacco smokers are now being seen in young cannabis users. A case of emphysema showing a pair of lungs shot through with holes from cannabis use is yet another item in this sorry saga.

Effects on the reproductive system and children
Cannabis can suppress ovulation in women and if they smoke when pregnant, the baby will be lighter and have a smaller head circumference. A long running study of children in Canada by Peter Fried has discovered deficits in their cognitive functioning at 9. One form of leukaemia is 10 times more common in these offspring.

A reduction in sperm count and the presence of abnormal sperm has been documented for years. Some men complain of impotence. Cannabis smoking in the previous hour has been associated with a fivefold increased risk of heart attack in middle-aged people.

The gateway effect
Australian researchers found that weekly users were 60 times more likely to move on to other drugs, the strongest association being in 14 to 15 year olds. A possible genetic link was dismissed by a study of 300 pairs of same-sex twins in New Zealand. Use of cannabis by one of them before the age of 17 meant that he or she was 2 to 5 times more likely to have drug problems and dependency later in life, than their sibling. Professor Denise Kandel and her team in the USA have researched this topic for the past 20 years or so. They have consistently found that level of usage is a major factor.

Medical Use
Pure synthetic THC, Nabilone, is already available in the UK for the nausea of chemotherapy and the stimulation of the appetite in AIDS patients.51 No-one should have a problem with extracts of cannabis being purified and tested, as they are now in Britain, if, according to the EU rules for medicines they prove to be efficacious, but cannabis, per se, with its 400 chemicals would never pass the tests. Nabilone anyway is by no means the first choice of doctors because of its side effects.54 The warning on it reads, “THC encourages both physical and psychological dependence and is highly abusable. It causes mood changes, loss of memory, psychosis, impairment of coordination and perception, and complicates pregnancy”.

Keith Stroup, an American pot-using lawyer said in 1979, “We will use the medical marijuana argument as a red herring to give pot a good name”.

In conclusion
For a UK government which banned beef-on-the-bone with its infinitesimal risk of transmitting CJD, it is astonishing that they should relax the law on a drug which has been proved to be so damaging.


This digest is an extract of a much longer paper prepared by Mary Brett, BSc., Head of Personal, Social and Health Education at Dr Challoner’s Grammar School in Amersham, Buckinghamshire, England, and a former Executive Councillor of the National Drug Prevention Alliance. The full paper runs to 9 pages, including 54 technical references. The full paper may be requested from Mrs Brett by emailing her on mary.brett@dsl.pipex.com


For further extensive references and research digests on cannabis and other drugs, access the NDPA website on www.drugprevent.org.uk – and see also its links to several other sites in a range of countries.

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