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Cannabis, Cannabis sativa

News Stories About Cannabis

New information about substance abuse appears daily. For a somewhat random selection of stories relating to cannabis click here for the cannabis news archive.

Also known as

Cannabis sativa in bud

Cannabis sativa, the 'bud'

pot, hemp, bhang, marijuana, joint, reefer, wahupta [Sioux], dope, ganja, smoke, weed, herb, marihuana, hash, doobie, sinsemilla, leaf, green, greenbud, bud, 420, Alaskan thunderfuck, bc bud, hooch, stash, Thai-stick, thai-bud, Mexican, panama red, Colombian gold, bricks, pounds, kilos, ounce, gram, bag, baggie, green-sticky, dirtweed, shake, Indian hemp, ganjah, guaza, ganeb, kif, hanf, tekrouri, chanvre, hooter, bonghit, one-hit, shit, kineboisin, hamppu [finnish/suomi], kannabis, bangue, canamo, canamo indio, chanvre, ganeb, han ma, hanf, hint keneviri, hops, huang ma, huo ma, kenevir, kif, ma fen, ma jen chiu, mariguana, qunnab, ta ma, tchene, dagga, Mary Jane, boo, grass, moocah, tea, apocynum cannabinum, ace, Acapulco (color) afghani, indica, African, ashes, aunt Mary, bales, bamba, bhang, bo, bobo, boo, boo boo bama, buddha, bush, buzz, cest, cheeba cheeba, chronic, cryppie, cryptonite, dank, diambista, ditch, ditchweed, dobie, domestic don Juan, doob, doradilla, draf, fir, flowers, gash, gasper, gold, gong, grass green (ery), griefo grifa, griffa, gungun, Hawaiian homegrown hay, herba, high, homegrown, indica, indo, j, joint, kalakit, killer, leaf, leño, loco weed,  mari , maui-wowie, mj, mo, mota, number, panama (adjective), parsley, pr, pretendica, puff, ragweed, rainy day woman, rasta, red bud, reefer, roacha, root, seeds, skunk weed, smoke, spliff, stems, stone, texas tea, thaistickswisher, blunt, trees, twigs, untoque, wheat, weed, whacktabacky, whackyweed, wood, yeh, yerba, yerhia, yesca, humboltd, owl, hocus pocus, method, roach, mor a grifa, mootie, mooters, moota, moocah, thumb, thrupence bag, devilweed, sweet lucy, stick, stack, snop, smoke canada, shit, rope, shwag, nuggets, nuggies, dosia, diggy, blunt, ragweed, sweet wheat, draw, chief, cali, bowl, broccoli

What is Cannabis?

We like simple. Simple is good. We like to know that cocaine is bad without having to get involved in comparisons between powder and crack, between snorting and injecting. All substances come in a variety of forms and, hence, have a variety of effects.

But this is truest when it comes to cannabis. With marijuana* (the pressed flowering tops), hashish (the resin extracted from around the buds), hash oil (the essential oil) and, for some, consumption of the leaf and stalks, the forms in which cannabis can be consumed offer a wide range of active ingredients. Add to that differences in the means of consumption, smoking a joint, pulling a bucket, using a vaporiser, putting in food, etc., and the possible range of doses increases considerably.

Then, with cannabis, there is the added dimension of its complexity. There is increasing evidence that the balance between THC and CBN, the two main active ingredients, plays a major role in the effects of cannabis. But, overall, there are some 500 compounds in cannabis of which about 70 are believed to be psychoactive.

Making a universal statement about cannabis whilst ignoring all the possible differences in potency is ridiculous in itself but becomes more so when the question of contamination and adulteration are taken into account. There are people who claim that all the reported adverse effects of cannabis are due to contaminants and nothing to do with the 'pure' substance.

The July 2008 edition of 'Addiction' the journal of the Society for the Study of Addiction includes a review of the literature on cannabis potency and contamination. The review finds that there has been no systematic measurement of cannabis potency over time so claims that cannabis has become stronger can not be scientifically proved. The authors also found wide variations in strength within any period making it impossible to state with certainty that cannabis has increased in strength over time. They also found that there has been no systematic monitoring of contamination when studying the effects of cannabis.

The authors conclude that 'Claims made in the public domain about a 20- or 30-fold increase in cannabis potency and about the adverse mental health effects of cannabis contamination are not supported currently by the evidence'. They call for more research in order to obtain accurate information on the effects of potency and contamination in order to provide credible information for users on the potential for harm.

'Addiction' is a subscription only publication but an abstract of the review (opens new window) is available to the public.

Until we understand what is meant by 'cannabis' we will never get a clear understanding of the mechanisms for the harm which some cannabis use causes.

*Marijuana is often the name used in the USA for the whole plant and all parts of it and products made from it. Names in connection with cannabis soon become very confused.

What does it do?

There is no simple answer to this. Cannabis is a very complex substance and differing amounts of its principal ingredients seem to produce a variety of effects. Feeling relaxed and happy are common but many people get the giggles and become talkative. Hallucinations, such as feeling time is slowing down and senses are more acute are also reported but some people suffer anxiety, bordering on paranoia.

The main component of cannabis is delta-9-tetrahydrocannabinol, usually just called THC, but cannabinol(CBN) and cannabidiol(CBD) are also important. It is said that CBN softens the high resulting from cannabis use giving a more mellow effect. Since CBN results from the oxidation of THC, the effect of a block of cannabis can change over time.

As to its practical effects, these depend on who you believe. In the USA, in the 1930s, Henry Anslinger, the first head of the US Bureau of Narcotics, convinced people that cannabis caused what was called amotivational syndrome.  That is, users would become lazy and disinterested in the world around them. Propaganda films made at the time also stated as fact that cannabis led to violence and madness.

In the 1970s, a detailed scientific study of cannabis use amongst the working class in Jamaica was undertaken by the Institute for the Study of Man, supported by the U.S. Department of Health, Education and Welfare. The study was led by Vera Rubin and Lambras Comitas who co-authored a book 'Ganja in Jamaica' setting out their findings.

One key finding was that cannabis use made agricultural workers more thorough. When digging over ground they would use substantially more fork strokes, and expend more energy, under the influence of cannabis. This is not to say their work was better, simply that they paid more attention to it. In spite of this finding and in spite of the mass of evidence from regular cannabis users there are many who persist in depicting cannabis users as idle wasters.

Is it Addictive?

No. As simple as that. Cannabis does not meet the criteria for addiction; users do not become tolerant of it, they do not need ever increasing amounts to produce the same effects, and stopping its use does not produce physical symptoms of withdrawal. Also, it does not produce the cravings found with addictive substances.

In its 2006 annual report, the United Nations Office on Drugs and Crime, UNODC, says that many large scale users, who might be considered dependant on cannabis, regulate their use so that it does not interfere with their working lives which they would not be able to do if cannabis were addictive.

Of the estimated 162 million adult users of cannabis in the world there are, undoubtedly, some who would be described as dependant, finding that they do want to use cannabis very regularly, but that is not the same as addiction.

Is it Harmful?

Yes. For some people. The greatest problem with cannabis is knowing who those people are and understanding what it is that is doing them harm. There seem to be four ways in which cannabis can be harmful.

Hildegard was a 12th century German mystic.  About hemp she says ‘whoever is weak in the head and has a vacant mind, if that person will have eaten hemp, it easily makes the person suffer pain somewhat in his or her head.  However, whoever is sound in the head and has a full mind, it does no harm.’

This idea, that cannabis is harmful for some but not others, was also confirmed in the Jamaican study referred to above. In working class Jamaica, it was well understood that some people 'didn't have the head for it' and should, therefore, avoid cannabis use.

A paper in Biological Psychiatry published in April, 2005 found a possible genetic link meaning one in four people are predisposed to be harmed by cannabis. Further research, however, found no basis for this conclusion so there is still no explanation of cannabis' different effect on people even if the same dose, e.g. by passing a joint around a group of people, is being administered.

A 'bucket' bong

Diagram showing the principal
of a 'bucket' bong

The second way in which cannabis seems to cause harm is when very high doses are taken by young people whose central nervous system is not fully developed. The reason for the recent increased concern over the effects of cannabis results from the way in which young people maximise the dose they obtain. Use of a technique called 'Pulling a Bucket' can result in a very high dose of cannabis being inhaled in a very short time.

To try and illustrate the difference between smoking a joint, in the way many middle-aged people did and still do, and Pulling a Bucket, I make a comparison between sipping a gin and tonic and pouring a whole bottle of gin down the throat.

I have spoken to police officers and drug workers about their experiences of dealing with preteens suffering severe mental health effects as a result of this very high dosage use of cannabis as well as seeing a number of videos showing very young children using cannabis in this way.

The third way in which cannabis can harm and that harm be completely unpredictable concerns the way cannabis is produced. Cannabis may be accidentally contaminated during the production process, perhaps by excessive handling with dirty hands, or deliberately adulterated to increase its profitability to the dealer.

It is sometimes suggested that other substances like strychnine are added to cannabis to increase the high.  Though there appears to have been no detailed study, it does seem that cheaper grades of cannabis resin may well be contaminated with a variety of unpleasant substances as a result of poor handling techniques rather than deliberate adulteration.
There is, also, another possible explanation for these stories of adulteration.  Robert Connell Clarke, in ‘Hashish!’, explains that hand-rubbed cannabis resin may contain more moisture than is desirable and may also be contaminated by the simple fact of its being produced by hand-rubbing.  This can lead to the formation of mould, often in the form of white threads, which becomes visible when a block of resin is broken open.  Dealers, faced with the prospect of having to discard stock which has degraded in this way are thought to tell gullible buyers that the threads are composed of opium or other substances which have been deliberately added to increase the effect of the cannabis.

There are many ways in which cannabis may be deliberately adulterated to increase its bulk or to change its appearance to make it seem stronger and, hence, more valuable. The most harmful of these is the production of 'grit weed' detailed further down this page.

The fourth thing which makes cannabis harmful is being illegal. As an illegal substance, many users are forced to become involved with criminals unless they are able to grow and produce their own supplies. This involvement in criminal activities may erode respect for society leading to an erosion of citizenship even if a user goes uncaught. But, for those who end up being brought into the criminal justice system, their use of cannabis may, at least, blight their lives and, at worst, lead them to becoming involved in other criminal activities not directly related to the use of cannabis.

Grit Weed

First reports of ‘grit weed’ began appearing on the Internet in February 2006 but it was 2007 that it became more widely available.

It would seem that the clampdown on cannabis production towards the end of 2006 may have made the situation worse because a reduction in availability has led regular users to turn to different suppliers with whom they do not have a relationship based on trust.

Cannabis sativa, a thriving plant

A thriving Cannabis sativa

Smoking ‘grit weed’ can lead to coughing and sore throats and may, in the longer term, result in silicosis, a potentially fatal lung condition.

Whilst there is evidence of cannabis being contaminated with a variety of substances to bulk it up and increase the dealers’ profits, it would appear the true ‘grit weed’ is a more sophisticated scam.

To produce ‘grit weed’, growers are spraying plants with an industrial spray used to produce frosted glass about seven to ten days before harvesting.  This deposits small glass beads on the buds of the plant and allows time for further cannabis resin to form around them.  When harvested, the beads are fully incorporated in the resin and can glint in light in a similar way to the glint produced by crystals of THC, the main active ingredient in cannabis.  Thus, ‘grit weed’ looks, on simple examination, to be high THC resin.

So, as well as being bulkier which means that an ounce of resin may appear to be up to 25% heavier, true ‘grit weed’ can be sold at a higher price per ounce because it appears to be higher quality.

It is said to have originated in the Netherlands and is only sold to the UK as only UK users are ‘stupid’ enough to accept it.  Other reports, however, suggest that it is produced in two Welsh cities by two well known gangs.

Smoking ‘grit weed’ has already caused problems of coughing and throat irritation but it is the longer term effect which is the more worrying. Silicosis is a severe lung disease caused by inhalation of silica particles.  It caused many deaths amongst mine-workers and stone cutters as many rocks contain silica particles and silicates.  Speaking on ITV Wales Eggsy, a member of the rap group ‘Goldie Lookin Chain’, said that two puffs of a joint made with ‘grit weed’ had given him a sore throat and a friend of his had lost his voice for a time.

Many stories about adulterated drugs which appear in the mainstream press turn out to be distortions or exaggerations and present a picture which is far scarier than the reality.  In the case of ‘grit weed’, however, it seems that its potential harm cannot be overstated.

On Internet blogs associated with the use of cannabis and other drugs there are numerous postings warning of the dangers and pleading with users to be on guard against being offered ‘grit weed’.  There are also suggestions that some people are turning to other substances instead of cannabis without considering the harm those substances do.

There have been suggestions that some producers of 'grit weed' have turned to using contaminants with a much smaller particle size making detection much more difficult.

There are some voices which say that, as cannabis use is illegal, any harm done to users by ‘grit weed’ ‘serves them right’.  My attitude is that abusing any substance which risks damaging your health is a foolish thing to do and it doesn’t matter whether the substance is legal or not.  The production and sale of ‘grit weed’ is just another example of how unscrupulous suppliers are willing to exploit their customers for the sake of increased profit.

For more information on grit weed visit

Cannabis and Mental Health

Clearly, that cannabis changes brain function during the period of intoxication is undisputed but there is a long-running debate about whether use of cannabis can result in mental health problems in later life.

There a plenty of cases where patients who develop schizophrenia or psychosis of some form report using cannabis earlier in life and this leads people to conclude that the cannabis use is the cause of the mental illness. It is often said that correlation is not causation but, with cannabis, even the correlation is weak. For many millions of cannabis users there are no later medical conditions which may be related to cannabis use.

Much research has been done, and is ongoing, to see if a link between cannabis and mental illness can be conclusively demonstrated. Conducting such studies is complex because it is difficult to allow for all possible factors which might result in illness in later life. Also, when done retrospectively, as most such studies are, there may be problems with the recording of things like past cannabis use

In a paper published in the September 2009 edition of 'Schizophrenia Research', scientists from Keele University and its Medical School report that they found no evidence of a causal link between cannabis and mental health in a study of 600,000 patients per year for the ten years from 1996 and 2005.

The researchers studied the UK General Practice Research Database (GPRD) and determined the rate of cases of schizophrenia and psychoses in each of the ten years. This period coincides with substantial increases in cannabis use twenty years previously.

They found a significant decrease in the prevalence of schizophrenia over the period and a decrease in psychoses for the period 1999 to 2005 though there was no significant change over the full ten years for psychoses. To ensure that this was not part of a general trend of decreased consultation with GPs, the researchers looked closely at a sample of 35,000 patients and found that the rate of consulting a GP for any condition increased over the period.

The researchers note the limitations to their study, particularly that they looked at overall populations and did not look specifically at cannabis users, but conclude that, at the very least, the study shows that the hypothesis that there is a causal link between cannabis and schizophrenia/psychoses is not supported by the evidence.

Results from this study are in line with a number of other studies but a much smaller study, in Zurich, did find an apparent link.

A possibly important piece of research is currently underway. In this study, researchers have looked at the incidence of cannabis use in England and projected the number of schizophrenia cases which should arise in 2010 if there is a causal link. By conducting what is called a prospective study, that is looking forward, the researchers can eliminate any tendency to look for ways to make the data match their hypothesis.

What none of these studies has been able to consider, however, is the quality of the cannabis consumed. In the October 2008 issue of 'Addiction' researchers reported on the amount of ammonia given off by heating cannabis in a vaporiser. The research was intended to examine the contention that vaporisers were a safer method of using cannabis than smoking. As part of the work, however, they discovered that, on average, 'street' cannabis produced ammonia levels twenty times higher than those from cannabis grown under controlled conditions specifically for research purposes.

Thus, we are left not only unsure whether cannabis use causes mental health problems but also unsure as to whether any such problems are the result of the cannabis or contaminants introduced during its manufacture.

Cannabis - the Gateway Drug

There are those who claim that cannabis use leads on to the use of 'hard' drugs. Faced with someone who has lost a family member to heroin and is convinced that it was cannabis which started them on the road to self destruction, it would be easy to agree. But, there is no way of proving that the person who died from a heroin overdose would not have become a heroin addict even if no such thing as cannabis existed.

In the United Kingdom, approximately 3.5 million adults use cannabis at least once a year and there are around 300,000 problem heroin users so clearly there is no inevitable progression from one to the other.

There are studies which show that a high proportion of addicted drug users began by using cannabis and this is used to argue that cannabis leads on to more harmful drugs. The problem with that argument is that it may be an example of the principle of post hoc ergo proptor hoc, a later event happened because of an earlier event, whereas there is no evidence for a causal link.

The United Nations Office for Drugs and Crime puts forward another view. In its 2006 World Drugs Report it quotes research which ‘concludes that associations between early cannabis use and later drug use and abuse/dependence cannot solely be explained by common predisposing genetic or shared environmental factors. [The research] argue[s] that association may arise from the effects of the peer and social context within which cannabis is used and obtained. In particular, early access to and use of cannabis may reduce perceived barriers against the use of other illegal drugs and provide access to these drugs.’

In other words, because cannabis is illegal people who use it become acquainted with a criminal world in which ‘harder’ drugs are also available and lose their inhibitions about buying illegal substances.

My own view is that telling lies about cannabis may be the mechanism which makes it a ‘gateway’ drug. If young people are told that cannabis is extremely harmful and that use will lead to idleness, aggressiveness and mental health problems they are highly likely to find their own experience of it to be markedly different. If they are now told that heroin is an addictive substance which leads to many deaths each year due to overdose, they may look at the situation regarding cannabis where they were lied to about its effects and assume that what is being said about heroin, or any of the other ‘hard’ drugs, is also lies.

This view seems to be supported by a study, published in December 2008, entitled 'Expectancy Change and Adolescents’ Intentions to Use Marijuana' (opens new window) which found that young people were more likely to continue to use cannabis if their initial experience of it did not live up to the harmful expectations which they had as a result of exaggerated drug education messages.

Should Cannabis be Illegal?

There is evidence that cannabis use is decreasing but it is not, yet, clear whether that decrease is related to the reclassification of cannabis as a Class C substance or simply that substances undoubtedly do go out of fashion. If cannabis use is decreasing as a result of its reclassification then that is one argument for going further and removing its classification altogether.

In looking at the status of cannabis it is necessary to consider why it became illegal in the first place. Much has been written about Henry Anslinger, the first head of the US Bureau of Narcotics, and what motivated him to pursue cannabis in the way that he did. There are also those who suggest that William Randolph Hearst made his newspapers support Anslinger’s lies because he was fearful of the effect on his investment in pulp paper mills that use of cannabis fibre to make paper would have. Whatever the truth about why these, and other, people were so keen to see cannabis outlawed, there is no doubt that most of the evidence against cannabis was falsified.

The undeniable fact that cannabis became illegal because lawmakers were deliberately misled is another argument in favour of re-examining its status in the light of current knowledge. Sadly, that is not going to happen since, in the UK, Prime Minister, Gordon Brown, has ignored the advice of his own experts and decided to reclassify cannabis as a Class B substance. Yet again, political expediency has been put above real efforts to reduce harm.

Then there is the question of whether the law is having any effect at all. There is no survey data available to answer the question; if cannabis were legal would a substantial number of non-users become users? That is to say, are there people for whom it is only the illegal status of cannabis which stops them using it? In my own case, I have never used cannabis and I have no desire to; Tesco could give cannabis away instead of Clubcard points and I would not be interested. So, for me, the question of whether cannabis is legal or illegal makes no difference and that is certainly the case for those who do use cannabis and may be the case for many of those who do not.

There is anecdotal evidence from The Netherlands and Australia that decriminalising cannabis does not lead to an explosion in usage. The Netherlands, which tolerates the use of cannabis in its famous 'coffee shops', has an annual prevalence rate around the middle of the European league table. Some Australian provinces tolerate individual cultivation and consumption of cannabis but their prevalence rates are not statistically different from those of provinces where the law is strictly enforced.

It could be argued that, if cannabis use is unaffected by its legal status, what does it matter if it remains illegal? But, if respect for the law, in general, is to be fostered then there is a duty on governments not to maintain unnecessary legislation on the statute books.

But the compelling argument for changing the law in relation to cannabis is a simple one; at a time when there is increasing regulation of herbal remedies, homeopathic potions and food additives of all sorts, is any government which tolerates the use, by a large proportion of its population, of a substance manufactured with no quality controls of any sort anything other than criminally negligent?

I am not, for one moment, saying that cannabis should be wholly legal and freely available to anyone but I do believe that its use should be subject to regulation and that cannabis, up to a certain strength, and properly tested for its quality, should be licensed for sale to over 18s. At the same time, penalties for supplying cannabis above the approved strength, or to minors, should be substantially increased.