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Cannabis News Archive

So What WAS in the News?

Substance abuse, whether legal or illegal, is so widespread in modern society that there are many stories about it in the news everyday.

This page contains stories which were, originally, placed on the Substance Abuse News page but which can no longer be called 'News'.

In addition to items specifically about this substance there are many items related to substance use and misuse in general. These general items can be found in the 'All Substances News Archive'.

Please go to the 'Phantastica' page to access stories related to specific substances.

DEA Administrator Says Cannabis has No Medical Use.
22nd July 2011

The USA's Drug Enforcement Administration Administrator, Michele M. Leonhart, has said that cannabis has no 'accepted' medical uses. For a discussion of what she might mean see my blog.

Is Cannabis a 'Gateway' Drug?
19th July 2011

A new paper from Australia claims that users of cannabis are more likely to move onto other drugs. But, what it doesn't do is demonstrate that the cannabis use is the cause of the migration. You can read more on my blog.

Proposition 19 Fails in US Mid-terms
4th November 2010

Proposition 19, the Californian proposal to make growing and possession of small amounts of cannabis for personal use failed to gain the required support when voted on as part of the mid-term elections.

It seems that a number of factors reduced support as the campaign developed. Proponents had focussed on the decrease in crime that would result from not bringing cannabis from Mexico illegally but a number of people analysed the data to show that the effect would be small since most Mexican cannabis passes through California on its way to other states where it would still be illegal. The amount to be gained from tax was also shown to be over-stated, that is to say more people believed the argument that there was not a large gain to be made.

It also seems that some users of cannabis did not support the proposal for the simple reason that California already turns a blind eye to a lot of small scale use so they didn't think Prop 19 went far enough.

Finally, it appears that areas where cannabis for medical use is grown voted against because of fears, probably justified, that Prop 19 would have reduced the 'medical' need for cannabis and affected incomes in those areas.

The general swing to the right seen throughout the USA may also have had an effect on this particular referendum.

The campaign, however, brought the debate about cannabis into the mainstream media and it is likely that further proposals will come forward, nationally and in other states.

Blarney Castle in Drugs Raid
22nd October 2010

Earlier this year, I provided some suggestions to the head gardener at Blarney Castle about the poison garden they were putting in to add to the attractions for visitors. I also gave permission for them to use material from this site on the information boards around the garden.

They wanted to include the plants which affect the brain more than anything else and planted five Papaver somniferum, opium poppy, and one Cannabis sativa. In the Republic of Ireland, growing either of these plants is illegal. The poppy ban is ineffective as most garden centres sell the seeds every spring.

Blarney Castle consulted the Irish police, the Garda, who raised some concerns and said they would be in touch about whether they would issue a licence for growing these plants. Now, in the UK, people would take no action until a licence had been issued but Blarney Castle took the view that silence betokens consent and, when they heard nothing more from the police, went ahead with the planting.

Everything was fine and the plants have been seen by the many visitors to Blarney through the summer. But then, on 15th October, a reporter rang the Garda for an official comment on the illegal growing of these plants. On Thursday 21st October, Garda officers visited Blarney castle and removed the poppies and the cannabis. The owner was told he could face prosecution under the Misuse of Drugs Act.

California Proposition 19 'Too Close to Call'
10th October 2010

The USA's electoral system allows states to vote on referenda on specific items of law and enables individual citizens to put forward 'propositions' if they can show sufficient support.

In California, use of cannabis for medical purposes is tolerated, almost to the point of being legal. In theory, the federal government could act against it but President Obama signalled that he felt that would be a waste of federal money.

At present, different local areas in California take different views on the subject with some trying to use planning laws to prevent 'dispensaries' from operating while others make little effort to ensure that those buying cannabis have a proper medical need.

In November's country-wide mid-term elections, Californians will vote on Proposition 19 which would make it legal for over 21s to grow cannabis and possess up to one ounce for personal use.

The full title of Proposition 19 is Regulate, Control and Tax Cannabis Act of 2010 and, under California law, it needs only a simple majority of those voting to become law immediately. The inclusion of 'tax' in the proposal seems to be key since, at a time when like, so many governments, California is facing massive budget cuts an additional source of revenue coupled with savings on unsuccessful enforcement efforts may sway many who have no interest in cannabis use.

As polling day nears, so the debate intensifies and the view of those closest to the issue is that it is not possible to predict the outcome.

There is little doubt that the present position is chaotic and does not allow for proper quality control of cannabis being supplied. The questions are whether Proposition 19, if it passes, will result in a properly regulated system or, if it fails, will lead to a backlash against the existing situation.

Exploring the Fault Lines in 'Joined-up Government' - Cannabis & Skiing.
10th October 2010

The UK government commissioned a report into the perception that the ''elf 'n' safety' culture that has spread though the UK in the past decade or so has had a corrosive effect on a range of activities from school sports to traditional village festivals which have run for hundreds of years.

The report's author, former Conservative minister Lord Young, set out his view that the common sense should be put back into safety policy and that attempts to create a completely risk-free world were ridiculous.

Lord Young was interviewed on BBC Radio 4's 'Today' programme and said ‘Frankly, if I want to do something stupid and break my leg or neck, that’s up to me.’ Pressed by Evan Davis to confirm that view, he went on 'haven’t you ever been skiing?'

Anxious to see if this would be principle the government would apply across all policy areas Davis asked, 'So if I want to smoke cannabis, that’s up to me as well, presumably?

‘What principle distinguishes between me doing something dangerous that can break my neck and having a spliff?’

Lord Young's only response was that smoking cannabis is illegal. So, it seems we have the UK government considering changing the law to enshrine the principle that people can decide for themselves what risks to take when it comes to physical activities but blaming the law for not allowing them to apply that same principle to the use of cannabis.

Simon Jenkins on Cannabis in California

One side effect of the travel chaos caused by the Icelandic volcano has been that stranded journalists have had the opportunity to take a closer look at subjects than their normal schedule permits.

The well-known writer and former newspaper editor, Simon Jenkins, took a close look at the 'medical marijuana' situation in California after finding himself stuck in Los Angeles.

His piece in the London Evening Standard (opens new window) finds that the current situation is somewhat confused since, in the right circumstances, use is now legal but supply remains an offence. There are also variations in what constitutes 'medical need'.

In November, California will vote on a proposal to make growth for personal use and possession of up to one ounce completely legal ending the facade of medical need. Ahead of that vote there is the inevitable backlash with moves, at local level, to reassert a more strict control regime.

Jenkins makes a point of stressing that he regards 'cannabis as a potentially dangerous substance for many young people' but concludes that the regime which California may vote for later this year makes a great deal more sense that which makes London home to 'the worst drugs problem in Europe'.   

UNODC Revises 'Cannabis Laws' Web Page 

Some time ago, I reported how UNODC had deleted a part of one of its own web pages which suggested that the total prohibition of cannabis was not effective. (Click here to read that entry.)

UNODC has now published a completely new 'Part 4' (opens new window) which follows the hard line on cannabis much more closely with great emphasis being placed on its illegal status and alleged harms. It also claims, against almost all available evidence, that cannabis's illegal status reduces its use.

For UNODC to recognise, as the previous version of this page did, that the current regime, based on prohibition, isn't working would be a bit like turkeys voting for Christmas so it is no surprise that it prefers to adhere to the strict reading of the single conventions. It is, nonetheless, a little disappointing.

Medical Marijuana and the Law

An interesting piece in The New England Journal of Medicine written by Diane E. Hoffmann, J.D., and Ellen Weber, J.D. looks at the, frankly chaotic, situation in the USA over the use of cannabis for medical purposes. The authors note that nothing in any of the state laws being passed to allow for the use of 'medical marijuana' lays down any standards for quality or potency and that many whilst allowing the use of cannabis still prohibit its growth and take no line on whether it may be sold to patients.

They also note that the recent announcement that the Federal Government will not pursue users if they conform to state laws is, simply, an informal guideline and could be reversed at any time.

My fear is that approaching the question of cannabis use for medicinal purposes in such a piecemeal way is likely to result in more harm than good.

New Study into Adolescent Cannabis Use

The Archives of General Psychiatry has published an Australian study examining the effects of cannabis use on later psychosis. The paper which is available free and in full by clicking here (opens new window) takes information from The Mater-University Study of Pregnancy which took 7,223 births in Brisbane between 1981 and 1984 and followed the offspring at 5, 14 and 21 years of age.

Though the study was supposed to be based on one child per mother, the long recruitment time meant that some second births were included. Of the 7,223 children originally recruited, 3,801 were studied at 21 years old, though due to funding shortages only 2,575 were fully assessed. Of these, there were 228 sibling pairs enabling the researchers to remove any confounding effects due to genetic or environmental factors.

The study found that there was a link between early cannabis use and later indications of psychosis. It also found that, in sibling pairs, psychotic indications were related to time since first cannabis use rather than family factors.

The study also found, however, that there was an association between reported visual or aural hallucinations at age 14 and later cannabis use. Those who reported having hallucinations by age 14 were found to be twice as likely to be daily cannabis users at age 21. This raises the possibility, reported in other studies, that propensity to mental health problems is linked with a tendency to use cannabis rather than the reverse.

It is important to note that the authors conclude that there is an 'association' between cannabis use and later mental health issues but not that the link is 'causal'.

This is not the first study which has suggested that early use of cannabis can be a problem and I doubt if anyone will be surprised by its findings. After all, we know that giving alcohol to young people is damaging so cannabis might be expected to have the same impact.

Though the authors set out to try and overcome some of the limitations of earlier studies, there are, inevitably, some problems. First, the number of subjects lost between recruitment (7,223) and full follow-up at 21 (2,575) may result in problems. It is impossible to know how many of those young people used cannabis and what effects it had. It could be that those who remained in the study were more likely to have had health issues making them more familiar with the workings of the healthcare profession.

The other, more serious, limitation is that there is no information on dose. Users are categorised purely on the frequency of use not on the dose administered at each use. It is important to know whether someone taking long pulls at a high-strength joint once a month is at more risk that someone puffing away, but barely inhaling, every day.

UNODC Censors Own Website

A couple of days ago, Transform Drug Policy Foundation stumbled across a page on the UNODC website about cannabis. The page forms part of a section called The Global Youth Network. It is described as a ' by UNODC to increase youth involvement with the international community in developing drug abuse prevention policies and programmes.'

A page entitled 'Cannabis: A Few Issues' contained four sections. Section 4 'The effect of cannabis laws' has paragraphs headed 'Reducing the severity of the penalty doesn't seem to lead to increased use', 'Laws don't seem to matter one way or another to young people' and 'Resources could be better placed elsewhere'. This was followed by the example of Canada where police are reluctant to use the full power of the law against young people found in possession of small amounts of cannabis.

The page, as a whole, does not call for cannabis to become legal but it does point out that excessive sanctions are counter-productive and that experiments with decriminalisation, in some countries and states of the USA, have shown that it does not have the detrimental effects some people predicted.

All of which is well understood by many people and the page has been on the UNODC site since 2006 without any upset. Just two days after TDPF found this page and commented on it of the Transform website, the fourth section of the page has disappeared.

It seems that it is still the case that the only 'facts' about illicit substances which are acceptable to the UN and its members are those which do not challenge prohibition in any way.

Perhaps UNODC has never heard of the Internet Archive Wayback Machine which has the original (click here). For comparison purposes,  the latest version of the UNODC page is here.

For further information on this story, visit the TDPF blog. (Clicking links to external websites opens a new window).

(Click here to return to the update on this.)

Cannabis and Schizophrenia

Contrary to the belief of many people, especially parts of the media, there has been no proof that cannabis use causes schizophrenia. There is some evidence that it may worsen the condition for existing sufferers and that, in some cases, it may bring about the first manifestation of the condition for those who are destined to suffer it in any event.

Equally, there has been no absolute proof that cannabis does not cause schizophrenia. In many ways, proving a negative is much harder than proving a positive so this should be no surprise. Two newly published pieces of work have looked at two aspects of the issue of cannabis and mental health.

In a paper published in the November issue of 'Addiction', Hickman et al assume that there is a causal link between cannabis and schizophrenia and estimate how many people would need to stop their use of cannabis to be sure of avoiding just one case. They found that many thousands of people would have to cease cannabis use for one less person to suffer schizophrenia. Remember that this is assuming there is a causal link.

Their conclusion is that the resources necessary to possibly reduce the number of schizophrenia sufferers by one is out of proportion to any benefit derived and they argue that future work should focus on broader issues or psychosis rather than concentrating on schizophrenia. Efforts to reduce cannabis use should, they say, centre on all psychotic outcomes.

The second piece of work was the publication of the text of a lecture given earlier in 2009 by Professor David Nutt. Prof Nutt argued against the reclassification of cannabis to Class B and, in his lecture, he stands by that position and suggests that raising the class of a substance may increase its attraction.

Certainly, there was a notable reduction in cannabis use after it was downgraded to Class C but it cannot be said with certainty that the reclassification was the cause. It may just have been a change in fashion amongst young people.

Prof Nutt also points out that, in spite of the growth in cannabis use over the past thirty years and the fact that higher strength cannabis has been in more widespread use for ten years, there has been no massive upturn in the number of cases of schizophrenia. In fact, the reverse is seen with the incidence of schizophrenia in the general population declining.

Looking at the wider range of psychotic incidents, Prof Nutt quotes research suggesting that a cannabis user is 2.6 times more likely to have a psychotic episode than a non-user. As a measure of relative risk, however, he points out that smokers are 20 times more likely to get lung cancer.

Study Links Lying to Increased Cannabis Use

NIDA, the National Institute on Drug Abuse, which is part of the National Institutes of Health (NIH) , a component of the U.S. Department of Health and Human Services, reported in September 2009 on a paper published in December 2008 in 'Psychology of Addictive Behaviors', the journal of the American Psychological Association.

The paper entitled 'Expectancy Change and Adolescents’ Intentions to Use Marijuana' (opens new window) was written by researchers at the School of Behavioral and Organizational Sciences, Claremont Graduate University. They found that exaggerating the effects of cannabis makes young people more likely to continue using it when their first experience fails to live up the picture painted by anti-drug campaigns.

The researchers concluded that 'At a minimum, these results warn against overstating marijuana harms in prevention'. 

This study supports our belief that one way in which cannabis may be a gateway drug is because young people find it is does not cause the problems they have been told about and conclude that all the drug education they have received is flawed.

Researchers find no Link between Cannabis and Schizophrenia

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.

Their findings accord with a number of other studies but one, a small study in Zurich, did find an apparent link. Reasons for this result remain unknown.

The researchers note the limitations to their study, particularly that they looked at overall populations and did not look specifically at cannabis users, but concludes 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.

Argentine Supreme Court Rules on Personal Possession of Cannabis

In a case involving five young men arrested for being in possession of 'a few marijuana cigarettes', the Supreme Court in Argentina has ruled that it is unconstitutional to punish people who have cannabis for personal use.

The court said that "Each adult is free to make lifestyle decisions without the intervention of the state". Commenting on the judgement, Supreme Court President Ricardo Lorenzetti said private behaviour was legal, "The state cannot establish morality".

The Court stopped short of advocating complete decriminalisation, a move thought to be aimed at placating conservatives and the church.

The government has indicated its support for the Supreme Court ruling and is expected to put amendments to the existing drug laws before Congress.

This news from Argentina follows similar rulings in Venezuela, Ecuador and Colombia. Mexico recently changed its laws on all drugs to follow the Portuguese example of treating drug use as a health issue.

These moves by South American countries indicate a significant move away from 'the decades-old US-backed policy of running repressive military-style wars on the drug trade', according to the BBC website.

Mexican Forum on Cannabis Decriminalisation

For over one hundred years, Mexico's official policy on cannabis has been even harsher than the USA but, faced with over 6,000 murders a year due to drug trafficking, there are signs that the situation may be beginning to change.

In April 2009, the Mexican Congress convened a forum to discuss possible reform of the law on cannabis. A recent poll showed only 14% of Mexicans in favour of reform, against 40% in the USA, but the forum indicates a growing recognition that a great many of the harms caused by drug use are the result of drug policy rather than the substances themselves.

Cannabis and Treatment - Missing the Obvious

On 14th April both the Daily Mail and the Daily Telegraph ran stories based on a written reply to a parliamentary question. (Click on the names to view the articles in a new window.)

The answer concerned confirmed that the number of people seeking help with cannabis dependence doubled in the three years that cannabis was a Class B substance rather than Class C. For young people the increase was one third.

Both papers huff and puff about these increases being the result of the lowered classification and repeat the usual canards about higher strength, cannabis 'causes' schizophrenia, etc. The Mail quotes Mary Brett of Europe Against Drugs as saying 'When you relax penal policy against a drug like this, levels of use increase'. This is quite simply untrue because reclassification coincided with a significant fall in cannabis use.

It would, of course, be as wrong to state that reclassification resulted in lower usage as it is to state that the increase in treatment demand is the result of the Class C status.

What seems possible is that the lower classification meant that more people who were having problems with their use of cannabis felt able to come forward for treatment without the fear of having their lives and families destroyed by draconian legal sanctions.

If anything, and the sad thing is that there is little chance of proper research into this proposition, the reclassification as Class C was beneficial since many of those seeking treatment would have had a successful outcome.

Cannabis and Testicular Cancer

Researchers from the Fred Hutchinson Cancer Research Centre, the University of Washington and the Vanderbilt University Medical Center in the USA say that men who have ever used cannabis may be more likely to develop testicular cancer.

The research was the first stage in testing the hypothesis that the known presence of cannabinoid receptors in the testes might mean that cannabis use could affect their biochemistry.

The research was a case-control study matching 369 men with testicular cancer to 979 men without the disease. The research found a small but significant link between any cannabis use and testicular cancer. Ongoing, current use was said to show a much greater significance.

There was an observed higher level of close family members also having testicular cancer amongst the patient group compared to the controls and it is not clear to what extent this confounder was eliminated in the analysis.

The researchers, themselves, conclude that their work does not establish a causal link. Rather, this simply indicates that the hypothesis has not been disproved and much more work is necessary to test it further. This has not, of course, prevented the mainstream media from leaping onto the tentative results and presenting them as firm evidence.

Cannabis 'The Evil Weed' - 'Horizon' BBC TV

On 3rd February 2009, 'Horizon', the BBC2 science programme featured addiction specialist Dr John Marsden looking into the science behind cannabis.

Overall, the programme did its best to avoid the emotive issues surrounding cannabis use but it did give more time to the very small number of people who have mental health problems which may, or may not, result from cannabis use.

The most interesting research was an indication that any impairment in brain function may arise from early use of cannabis, say before the age of fifteen, but that use after that time does not seem to cause any lasting effect on memory.

Sadly, the science based stance of the programme was completely destroyed in the last fifteen seconds when Dr Marsden stated that his main concern was that 'the most significant damage caused by cannabis is subtle...It's the thousands of regular smokers whose lives are held back. It's the apathy, the sitting around smoking and not getting things done. The valuable, precise opportunities of life are lost.' In this way, without offering one piece of scientific evidence to support it, he repeated the canard about 'amotivational syndrome', the invention of Henry Anslinger.

But, of course, Horizon and the BBC could not be seen to be suggesting that the legal status of cannabis is wrong so, it was inevitable that the programme would come out against cannabis regardless of the science.

'Cannabis' Milkman gets Suspended Sentence

A 72 year old milkman from Burnley in Lancashire received a suspended sentence after admitting that he provided small amounts of cannabis to some of his elderly customers who found it useful to help ease their aches and pains.

In July, 2008, police became aware of his activities and raided his home and searched his van. They found cannabis with a total value of £450.

Cannabis Reclassification Completed

On 26th January 2009, the reclassification, under UK law, of cannabis as a Class B substance rather than Class C took effect.

By implementing this change, the UK government went against the advice of its own advisory body the Advisory Council on the Misuse of Drugs (ACMD). The ACMD produced a report with 21 recommendations, the main one being that having cannabis as a Class C substance was the best course of action.

The government's response trumpeted its acceptance of 20 of those recommendations, the only one being rejected was the reclassification issue.

The government has said that, whilst it accepts that cannabis use is declining, it is concerned about the increase in commercial growing in the UK. It seems possible, however, that the reclassification will have the reverse effect.

An unknowable number of people, currently growing a few plants for their own medicinal or recreational use, may decide that having cannabis permanently around the house is too great a risk for a Class B substance and decide to purchase 'street' cannabis in quantities just enough for their immediate use. If that occurs, the market for commercially grown cannabis will be increased not diminished by this action.

In effect, the government have created a Class B- with cannabis as the only substance in that class. This is because it is intended that first offenders, as far as possession is concerned, should receive a caution as happens now. On second offence a £80 on the spot fine would be imposed (once the government can get parliament approval for this measure). Only on a third offence of possession would the offender be treated in the same way as other people in possession of Class B substances.

It would seem that the reclassification is aimed at quieting critics of the pragmatic Class C status without overburdening the police with the need to apply the full rigour called for with Class B substances.

Is Cannabis Good for the Brain?

In what's called a 'poster' presentation to the annual meeting of the Society for Neuroscience on 19th November, 2008, scientists from the University of Ohio reported on trials on rats which suggest that THC, the active ingredient in cannabis, may reduce inflammation in the brain which is known to be a feature of Alzheimer's disease.

Gary Wenk, professor of psychology at Ohio State and principal investigator on the research said, “Could people smoke marijuana to prevent Alzheimer’s disease if the disease is in their family? We’re not saying that, but it might actually work."

Wenk stressed, however, that the work is not aimed at finding a cannabis based drug to treat Alzheimer's but is rather using the artificial THC like drug to find out more about the mechanism of the disease.

More details are available on the Ohio State University website. (Opens new window.)

Should Cannabis be Regulated?

In 1998, the United Nations established a ten year strategy for dealing with illegal drugs. That strategy is to be reviewed next year and a number of organisations have already made submissions to the UN for consideration.

The latest is the Beckley Foundation which, according to its website 'is a charitable trust that promotes the investigation of consciousness and its modulation from a multidisciplinary perspective.' At a two day seminar held on the 2nd and 3rd of October in the House of Lords the foundation launched its report 'Where can we go with Cannabis Policy?'

The report concludes that making cannabis available via a well regulated system with controls on potency and age restrictions for buyers would result in must less harm that the present situation where large numbers of people are criminalised only because of their use or supply of cannabis.

It argues that the harm caused by cannabis, with only two deaths ever being ascribed purely to the use of the substance, is much less than that of alcohol or tobacco.

Most commentators on the report, however, conclude that, with the British government intent on reclassifying cannabis from class 'C' to Class 'B', in spite of the advice of its own advisors, there is little chance of the foundation's recommendations receiving official support.

Click here to go to the Beckley Foundation website. (A new window will open.)

'Safe' Use of Cannabis

Proponents of the use of cannabis for medicinal purposes have to overcome the argument that the act of smoking cannabis is itself unhealthy. For many of these people the development of commercially available vaporisers seemed to solve this problem. These vaporisers heat cannabis enough for it to give off its active ingredients without causing combustion.

New research, conducted at Keele University in Stoke-on-Trent has identified a new, potentially very serious, problem with vaporisers. The researchers measured the vaporisation products from samples of confiscated cannabis, provided by the Home Office, and compared them with the products from 'standardised' cannabis supplied by the USA's National Institute on Drug Abuse (NIDA) and the products of smoking cannabis.

The results showed high levels of ammonia in the street cannabis samples which were not present in the NIDA samples. It also showed that, when smoked, most of the ammonia produced is in the sidestream smoke, that is the smoke from the burning tip which is not inhaled.

Ammonia, when it reaches the brain via the bloodstream, is the cause of the brain damage in horses arising from eating hay contaminated with Senecio jacobaea, ragwort. There is little known about the effects of ammonia inhalation in humans except that an accidental release, producing airborne levels of ammonia similar to those found in the research, caused neurobehavioral impairment lasting up to 22 months.

The researchers were unable to say whether the ammonia resulted from contamination or adulteration of the street cannabis samples or whether the lower levels seen with the NIDA samples were the result of the lower THC level in the NIDA sample.

It seems that the proper way for people to be able to have the medicinal benefits of cannabis is for it to be prepared in quality controlled conditions with a known THC level. Sadly, that is not possible whilst cannabis remains a proscribed substance.

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.

19 Year Old 'Shopped' by Father Gets 3 Years

When Neil Metcalfe found bullets in his son, Paul's, bedroom he called the police not knowing that they would find a firearm hidden under the bed.

Paul was sentenced to three years jail rather than the normal five years for firearms' offences because of his guilty plea and his father's action.

The court was told that Paul was looking after the gun and bullets for a contact he had made as a result of buying cannabis.

The story gives another clear example of the contention that much of the harm caused by cannabis results from its illegal status and not from the substance itself. If Paul Metcalfe had not gone to a criminal to obtain cannabis, he would not be facing a life-changing jail term.