W2B-028 Cannabis-0.txt
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CANNABIS

Cannabis is one of the oldest plants cultivated by man. Archaeological evidence from a Stone Age village, excavated on the island of Taiwan, suggests that mankind has been using the plant Cannabis sativa from earliest times.

The cannabis plant is a very adaptable annual, which can grow in most parts of the world including Ireland. In its chequered career, it has been grown for its long fibres known as hemp fibre, for its seed (hemp seed), used as a source of oil and for bird seed, and most notably for the intoxicating resin produced in its leaves, flowers and fruits. The drug form of cannabis has also been used for many centuries in many countries as a medicine. The characteristic chemicals called cannabinoids (of which there are at least 60 found in the plant) are currently being tested for use in modern medicine to treat glaucoma (a disease which causes gradual blindness), to prevent the nausea and vomiting caused by some anti-cancer drugs, and possibly to treat epilepsy.

The cannabis plant produces over 400 different chemicals, the most important of which are the main psychoactive compounds, the tetrahydrocannabinols (THC). However other cannabinoids may modify the effect of THC. Different cannabis products contain different amounts of THC. Herbal cannabis, known as marijuana, pot, grass or dope contains between 0 and 11% of THC, depending on the source. The resin, known as hashish or 'hash', contains between 1 and 26% THC. The resin is squeezed or scraped from the flowering tops of the plant, and then compressed into blocks or slabs and not allowed to solidify. This is the commonest form of cannabis used in Ireland. The strongest form of cannabis is an oil called 'hash oil' prepared by extracting or distilling the cannabinoids from the plant. This form generally contains about 30% of THC but samples containing up to 60% of THC have been encountered. Abroad it has been noted that the marijuana now on the market is at 7% of THC, over 600 times more potent than in 1974 and at times may be even stronger than hash even though the herb form is usually considered to be the weakest form of the drug. Little is known about the THC content of the cannabis drugs available in Ireland. One sample of cannabis grown in Ireland was found to contain nearly 4% of THC, while other samples were nearly devoid of any active drug. In Ireland cannabis is usually smoked in home-made cigarettes called 'joints'. In the case of the resin and oil they are usually mixed with tobacco. Cannabis can also be smoked in pipes, made into a drink or put into cakes or biscuits. The variation in THC content described above makes it difficult to accurately predict the effects of a given sample of cannabis. Adding to this variability is the fact that the amount of cannabis used per dose also varies considerably. One study has shown the THC content of street 'joints' to vary from 0.15 mg up to 41 mg where 5 mg of THC per joint would be the minimum for a drug effect to occur.

Legal Status

All cannabis products are controlled by the Misuse of Drugs Act. Cannabis is included in Schedule 1 which prohibits its medical and non-medical use. It is therefore illegal to grow, produce, supply or possess any of the drugs except in accordance with a licence from the Minister of Health for research or analysis. It is also an offence to allow premises to be used for cultivating, supplying or smoking cannabis. The penalties for possession of small amounts of cannabis herb and cannabis resin for personal use are, for a first offence, a fine of up to £ 300 imposed by the District Court or up to £ 500 in the Circuit Court. For a second offence, the District Court can impose a fine of up to £ 400, which rises to £ 1,000 if imposed by the Circuit Court. In the case of a third or subsequent offence, the District Court can impose a maximum fine of £ 1,000 or 12 months in jail or both. If the case is heard before a judge and jury, the maximum penalty can be an open-ended fine or 3 years imprisonment, or both fine and prison sentence. Cultivation, supply and possession of the isolated chemicals (cannabinoids) are treated more severely. (See section on Drug Laws for further details).

Prevalence and Availability.

Cannabis is apparently the most widely used of the illegal drugs but we have no idea of exactly how many Irish people have experimented with it, or use it regularly. There is little doubt that cannabis use has increased dramatically since 1969. A survey of university students in Cork in 1977 showed that 19% had experimented with the drug. The most recent indications are that 13% of Dublin post primary school children surveyed had used cannabis at least once. The experimentation rate increased with age, with 2.3% of those under 13 reporting use of the drug compared to 24.6% in those 17 or over. Experimentation rates in rural school children are believed to be lower than those in Dublin. Large numbers of patients attending the Drug Clinic report cannabis use, and prosecutions for cannabis-related offences represent between 60 and 70% of all prosecutions under the Misuse of Drugs Acts.

Prices for different cannabis products range from £ 1 per gramme of homegrown herb, to £ 3 per gramme of imported herb. Cannabis resin such as Lebanese Gold, Pakistani Black or Moroccan Red can cost between £ 5 and £ 10 per gramme. The cannabis smuggled into Ireland comes from a variety of countries in North Africa, the Middle East, the Indian sub-continent and America.

Short-Term Effects.

The effects of cannabis depend on a number of factors, including the type of cannabis used (hash and hash oil have greater and longer lasting effects than the relatively weaker marijuana), the way it has been stored (cannabinoids are unstable in light and air), the amount used, the way it is taken, and the experience, mood and expectations of the user.

When smoked, cannabis exerts its effects very quickly. The effects last up to one hour with low doses, and for several hours with higher doses. When it is eaten or drunk, it takes one to two hours to have an effect. The dose is not easily controlled and unpleasant reactions are more likely and more severe. Inexperienced cannabis users usually require some training in order to recognise the effects of the drug.

The sought-after effects, referred to as the 'high', include talkativeness, hilarity, euphoria, relaxation and a feeling of slowed time. Usual doses of cannabis also interfere with short-term memory and learning ability, with obvious implications for students and school-children trying to learn while 'high'. The more complex the task the more it is likely to be disrupted. Frequent heavy cannabis users are likely to have poor academic records, high levels of absenteeism from class and a high drop-out rate from the educational system. Moderate doses may also interfere with clarity of speech, resulting in communication of irrelevant words and ideas. Recent studies in adolescents show that impairment of recent memory in heavy cannabis users is still detectable after a 6 week drug-free interval. Adult cannabis users in the U.S. also report memory impairment and 45% of those surveyed stated that their ability to concentrate on complex tasks, to think clearly and to get things done was impaired. Motor co-ordination is also impaired at usual dose levels, affecting a person's ability to operate machinery, fly a plane or drive a car. This impairment lasts for some hours after the 'high'. Evidence continues to increase in other countries showing that cannabis contributes to the high level of fatal car, truck, airplane and train crashes among cannabis users. In many studies cannabis users report higher rates of traffic accidents than non-users and the percentage of those killed or injured in accidents who had been smoking cannabis is the same as for alcohol users. The very common combination of alcohol and cannabis produces greater damage than either drug alone, although little is known about the consequences of using cannabis and other drugs together.

An increasing number of cannabis users (especially the inexperienced) using the stronger forms of the drug now available report adverse reactions to the drug. These unpleasant reactions include fearfulness, confusion, severe panic and anxiety, paranoid reactions and hallucinations. These reactions, although frequently very frightening, rarely require medical attention and usually respond to reassurance. There would appear to be no danger of an overdose and no deaths in humans have been reported.

Long-Term Effects.

Because widespread regular use of cannabis by such groups as children, adolescents, girls and women is a relatively new phenomenon, the consequences of long-term use, particularly of the highly potent drugs now available, are less conclusively documented than the short term effects. A large number of studies with animals have consistently demonstrated toxic effects at doses comparable to those taken by humans who smoke marijuana several times a day. Studies of human cannabis users have been contradictory in their results and in many cases the evidence is inconclusive. This is probably due to the fact that the correct types of long-term studies on humans have not yet been carried out.

When burned, cannabis cigarettes produce three times more carcinogenic 'tars' than tobacco and five times more poisonous carbon monoxide. Prolonged heavy use of the drug causes chronic bronchitis, cough, hoarseness, laryngitis and pre-cancerous changes in the lungs similar to those produced by tobacco smoke, except that the changes and lung damage occur more rapidly with cannabis smoke. Cannabis tar is directly carcinogenic in animals and earlier predictions that long-term cannabis use could lead to cases of cancer in humans are proving accurate in that cases of lung, head and neck cancer have been reported in young cannabis smokers. In addition, babies born to mothers who smoked cannabis were, according to one report, ten times more likely to develop acute nonlymphoblastic leukaemia than babies whose mothers did not smoke cannabis.

Cannabis is not usually considered to produce physical dependence, although tolerance to the effects occurs, and physical withdrawal symptoms have been noted after cessation of heavy use. Psychological dependence has been noted in some users. Cannabis increases the workload of the heart and people who suffer from heart disease, angina and blood pressure are particularly vulnerable to the adverse effects of cannabis. Another high risk group are those with pre-existing mental illness, particularly schizophrenia and depression, because cannabis may trigger off a relapse or make symptoms worse. There has been a steep increase in the number of patients admitted to Swedish psychiatric hospitals with a diagnosis of acute anxiety, delirium, schizophrenia and psychosis attributed to cannabis use.

Among the other known or suspected long term effects of continuous cannabis use are decreased sperm count and sperm mobility, interference with ovulation and pre-natal development and impaired immune response. There is now a considerable body of evidence concerning the adverse effects of cannabis on both male and female reproductive systems. Not only does the drug affect the secretion of hormones and the reproductive glands directly but it also inhibits sexual activity and produces long-term alterations in the development of the reproductive system in male and female offspring in test animals. In addition, cannabinoid metabolites are highly fat soluble and remain in the body for several weeks. During that time the chemicals are concentrated in areas of the brain known to influence various aspects of sexual behaviour as well as in the endocrine and sex glands.

There is also increasing evidence of problems arising if cannabis is smoked during pregnancy because the infant is exposed to the drug via the placenta and also through breast milk after it is born. Studies in the U.S. report that up to 27% of pregnant women had used cannabis during pregnancy. The babies born to these mothers weighed less than those born to non-users and were significantly shorter in length. The cannabis babies had less muscle mass than normal and were more jittery, more irritable and less attentive. If the mother also used alcohol and tobacco, the combined effect of the three drugs was greater than any individual drug.
