Together we will beat cancer

Cannabis sativa

Cannabis cannot cure cancer

Earlier this week the Daily Mail reported that a young US boy’s brain tumour had been “cured” after his father secretly gave him cannabis oil through his feeding tube.

The bold headline hides a more important truth: the boy was also receiving high-dose chemotherapy, and it is this – rather than the cannabis oil – that is likely to have treated his cancer.

We were saddened to hear that the child in this story lost his life to cancer in November 2012, aged just four. [Updated 25/07/14 KA]  

Despite the headline, the story points out that the cannabis oil may well have helped to relieve some of the symptoms of the cancer, and treatment side-effects such as pain, nausea and appetite loss. But this isn’t the impression that you get from reading the headline, which arguably implies that cannabis cured the boy’s disease.

We felt it was important to emphasise this distinction. The role of cannabis and its derivatives in treating cancer is the subject of persistent internet myth and rumour, and we’re concerned that this headline may unduly fan these flames.

Cannabis and cancer – the state of play

One strand of the online rumours about cannabis and cancer is that there is some form of conspiracy to prevent research progressing into this area. This is not the case. In fact, we’ve previously written about how cannabinoids – the biologically active chemicals in cannabis – can slow the growth of tumours in lab tests.

But the fact remains that this work is still at an early stage. On top of this, there’s no robust scientific evidence to show that cannabis or cannabis oil can successfully treat cancer. And it’s possible that smoking cannabis can increase the risk of lung cancer.

At the moment, cannabis is illegal in the UK, although the medical use of cannabis and cannabis-derived chemicals is being investigated and debated.

Cannabinoids do have the potential to be useful for cancer and other diseases, but this needs to be explored in rigorous and safe studies. And accurate headlines about cases such as this one would help too.


Find out more


Anon October 3, 2011

there is a good side tho, more ppl are hearing about this cure for cancer.
As the U.S Health Service has started to patent various synthetic cannabinoids as cures for cancer the news will only spread further, and then cancer research business will die.

Jan O'Donnell September 12, 2011

I have watched the video on you tube ‘Run From The Cure’, I think it is atrocious that this treatment is being kept from cancer patients and chemo and radiation is being used instead, despite the devastation these treatments cause. Is THC treatment legally allowed in Britain at all or is the country as small minded as the States? If something helps a cancer patient they should have the right to try it and possibly be cured by it.

mike September 3, 2011

Why was my skin cancer cure time lapse video removed when the other video above was not? just curious. If people want to see it, youtube, cannabis cures skin cancer,blessings

Laura Davis September 1, 2011

Thanks for your response Kat and Peter. You have provided lot’s of information and I will try to work my way through it.

I was a little disappointed to hear that Cancer Research don’t instigate trials themselves as it is less accessible for members of the public to lobby researchers as we don’t know who they are!

If it was legal over here I would definately try making some as the anecdotal evidence seems so compelling but as it’s not and my dad wouldn’t entertain breaking the law, we’ll have to hope for a breakthrough in traditional medicine in the next few years. The problem is at 70 my dad’s unlikely to be eligible for trials as it seems they rarely invite his age group to participate.There seems to be a reluctance at a certain age to spend NHS money on expensive treatments which is understandable I suppose when you have a restricted budget. I was inspired by the modified T-cell research done by Dr Carl June which looks as though it could be promising for lymphoma but again I don’t think it would be available in time as my dad would probably be considered too old by the time it was ready, if he’s still with us. Anyway I’m going off topic but I hope that Cancer Research will support any applications from researchers if they receive any to test hemp oil and will lobby the governement to remove their restrictions for research purposes.

Mike September 1, 2011

Since there is photographic proof it cures skin cancer along with a copy of diagnosis online for all to see,why do you not accept it as proof?Yes,lack controlled studies ,i know but the time lapse does not lie! If you really cared you would get a small group of say5 people and do a underground controlled study on skin cancer and if it works, you would start to try it on other types.You say testimonials are not acceptable yet that is how side effect list for meds are generated.please respond

Peter Reynolds August 31, 2011

“To the best of our knowledge, we have not been approached by any researchers in the UK wishing to conduct trials of hemp oil for treating cancer.”

Kat, the Home Office has received multiple applications for licences to cultivate/import cannabis for medical research but dismisses them all out of hand. Unless your name is GW Pharmaceuticals you have no chance.

Such corruption and unlawful conduct is about to be challenged in the courts. What is astonishing to me and to many other commenters on this and other posts on your blog is that CRUK is not itself pushing harder for research into this area. Because it is politically incorrect you seem so easily deflected. There is an enormous body of evidence, anecdotal but also peer reviewed invitro and animal studies that demonstrate huge potential.

The power of cannabis is in modulating the endocannabinoid system which means its potential is in symptom relief as well as actually treating cancer.

CRUK should be standing up against the government and its obstructive position. It is pressure from the US DEA that is behind this and CRUK should act with a more independent and patient-centred approach.

Kat Arney August 31, 2011

Hi Laura,

We’re sorry to hear about your father. You may find it helpful to contact our Cancer Information nurses on freephone 0808 800 4040 (9am-5pm Monday to Friday), or by email ( They are happy to answer any questions you or your father may have about cancer and its treatment.

There is no reliable scientific evidence that hemp oil can cure lymphoma. The internet contains numerous anecdotal reports that cannabis or hemp oil can cure cancer – however, none of this data has been published in academic journals or made available for peer review (the accepted standard for scientific studies). As such, it is difficult to believe that there is solid evidence for the claims that are made.

Some studies have been done testing purified cannabinoids to treat a very small number of people with brain tumours, but their cancers were not cured (, ).

As we’re discussed at some length here and in this other thread (, there is evidence that specific cannabinoid chemicals may have an influence on cancer cells growing in the lab. And we have funded lab research into the effects of cannabinoids on bowel cancer cells.

There is no doubt that cannabinoids – both natural and synthetic – are fascinating biological molecules. Many scientists around the world are looking at cannabinoids with the aim of using them to treat cancer – if you are interested, a search of the scientific literature using the terms “Cannabi* cancer” pulls up more than 800 research papers:*%20cancer

However, because of issues with purity, safety, dosing, variations in chemical composition – not to mention the psychoactive properties of cannabis and its legal status in the UK – cannabis and hemp oil themselves cannot be considered to be suitable treatments for cancer.

As we’ve already mentioned (, how would you make sure that people were getting a reliable dose of the drug? And what about all the other contaminants from the plant matter? Much of the research into naturally-based drugs (for example, aspirin, resveratrol and curcumin) relies on purified chemicals, without the risk of confounding – and potentially toxic – contaminants. And chemists can research and tweak the structures of natural molecules to find something even more effective than the naturally-occurring chemical. This means that the dose can be controlled, and also the active substance can be given in much higher doses than might be possible from the natural product itself, to provide safe, reliable and effective treatments for patients.

The natural world has given us many useful chemicals which are showing great potential in the fight against cancer. Cannabinoids are likely to be another – but in the same way we wouldn’t suggest chewing vast quantities of yew bark to get a suitable dose of the chemotherapy drug paclitaxel ( we don’t suggest that cannabis can treat cancer.

Because of the way our funding system works, we do not commission specific clinical trials – rather, researchers come to us with project proposals, and those that of a suitably high scientific standard are funded (assuming there is enough money available). You can read more about how our funding process works here:

To the best of our knowledge, we have not been approached by any researchers in the UK wishing to conduct trials of hemp oil for treating cancer. As mentioned before, a trial of the cannabis extract Sativex is currently under way to test whether it can relieve cancer-related pain. There is no suggestion that it can cure the disease.

You may also be interested to read this post:’s-no-conspiracy-sometimes-it-just-doesn’t-work/

Best wishes,

Kat Arney, Science Information Manager, on behalf of Cancer Research UK

Matthew Sands August 31, 2011

Everyone agrees that Cancer Research UK should be looking into Cannabis Oil and testing it’s effectiveness. Everyone exept Cancer Research UK. To ignore this but to support synthetic cannabinoids research shows a disgraceful loyalty to pharmacuetical companies and disregard to cancer patients. Cancer Research UK claims there’s not enough “robust” evidence to support cannabis as a cancer cure, but i challenge Cancer Research UK to name me a currently approved cancer treatment that has as much evidence supporting it’s anti cancer effect. Cancer Research UK has contradicted itself with most of what it’s said, both denying and confirming an anti cancer effect of Cannabis. Plus Cancer Research UK have also admitted the useful sympton relief cannabis provides, yet will not support it’s use in anyway. Even if there’s debate over wether this boy (Cash) was cured by cannabis or Chemo, one thing is not in debate is that the Cannabis helped him through the chemo, yet Cancer Research UK will not even support it’s use as an anti nausea medicine. Shame on you, Cancer Research UK.

Peter Reynolds August 31, 2011

What an eloquent and heartfelt plea Laura. Any reasonable human being would support you 100%. I regret though that neither government, nor a politically correct institution like Cancer Research is likely to take any notice. Their focus is less on patients and more on preserving their own power base and certainly, definitely NOT pursuing anything that might undermine Big Pharma’s profits.

Cannabis oil is already proven to cure skin cancer but both US and UK governments maintain it has “no medicinal value”. “Proven” you ask? Well, physician doumented records satisfy me as proof although Big Pharma and government think otherwise.

Cannabis is already proven to minimise spasticity in MS and help with chronic and neuropathic pain.but only when it is marketed by GW Pharmaceuticals at 10 times the price that organised crime charges on the streets. If you have MS or cancer pain and grow your own for virtually nothing then again it has “no medicinal value” and, what’s more, you can go to jail for it.

The UK and US governments, GW Pharmaceuticals and a number of formerly eminent doctors and scientists are engaged in a conspiracy to misinform, mislead and deceive the public about cannabis and about GW’s Sativex which is nothing but cannabis but at a fantastically high price.

This “no medicinal value” story is a lie as hundreds of peer reviewed scientific studies prove. Big Pharma’s profits are sacrosanct though and government will alter and change the law and regulations as it wishes in order to keep the cash rolling in and prevent widespread use of this incredible medicine. Remember, mankind has used cannabis safely and effectively for over 5000 years. It is only in the last century or so that it has been prohibited.

As a last example of the evil hypocrisy and self-serving dishonesty of government and medical establishment, remember again that “no medicinal value” claim. Yet In 2003, the US government registered US patent no. 6630507 for cannabinoids as antioxidants and neuroprotectants for limiting neurological damage following stroke or physical trauma, or in the treatment of neurodegenerative diseases, such as Alzheimer’s, Parkinson’s and dementia.

These are the charlatans that we are governed by.

It would be fantastic if Cancer Research would leverage its influence to get proper trials on hemp oil (There are one or two people in Britain making it) but they will be told not to by the government and they will dutifully turn away.

If you want to do something to fight against this terrible evil, join Cannabis Law Reform (CLEAR), the UK political party that is fighting to make the truth about cannabis clear.

Laura Davis August 31, 2011

I am not pro or anti cannabis but am a daughter who’s father has just been diagnosed with SLL, non-hodgkins lymphoma. He is stage 4, there is no cure and he has been put on watch and wait. I am also a long time supporter of cancer research. For families like mine reading testimonials of people who have taken Hemp Oil and claim their tumours are shrinking and cancers are going in to remission, are very enticing when you have no hope of a cure through traditional medicine, particularly when the people promoting it are not asking a penny for their advice, so there is no scam involved. But I don’t want to persuade my father to give up six months of his possibly short life, going to live in another country, where we can legally produce this oil for him to try, if there is actually little chance of it being effective.
I feel that as an independent organisation it would be really helpful to families like mine, if cancer research would conduct a proper trial of hemp oil using the methods being promoted on the internet not to necessarily prove it’s effectiveness but maybe to disprove it. I really think there are many people who would be eager to try this oil, but won’t because it’s illegal so there would be no shortage of volunteers for the trial. It would be really inexpensive to fund this research as no expensive drugs are involved and if cancer research’s suspicions are correct, that hemp oil does not cure cancer then this trial would be conclusive and help many people make better choices for the last few months or years of their lives. If however the results were positive then this would provide great evidence that more resources should be put into developing safe and regulated methods of producing the oil.
I do feel as an organisation largely funded by donations from the public, Cancer Research should feel obliged through their research to formally discredit or encourage further research into Hemp Oil depending on their findings. It’s just not good enough to say that there isn’t enough ‘robust scientific evidence’ when that’s what your supporters expect you to be providing.
Please help those families vulnerable to these claims become better informed. I don’t trust your assumptions that hemp oil is ineffective as much as I don’t really trust their claims that it can cure cancer. You have the power and resources to prove or disprove these claims. Please take this opportunity. What have you got to lose?
As they claim that cancer can be cured with Hemp Oil within 2 -3 months surely a trial could be completed within a year.
Thank you.

Pax-Delta-Pan June 27, 2011

Again, sorry. Should be, “As much as mitigate Alcohol over consumption, which as CR UK knows damn well, Alcohol is a *cause* of cancers” not case.

Proofread, proofread, proofread, always do it, not proofread properly, doh. : )

Leon June 27, 2011

I would be most interested to see any comments from qualified medical practitioners about a certain Doctor Jurkovic
He published a paper entitled


Pax-Delta-Pan June 27, 2011

Sorry, “more and more are realising the era of prohibition allowed what are actually charlatans were allowed to prosper in career, reputation and status among the scientific community because they reinforced prohibition propaganda and were not questioned, such was the pitifully low amount of permitted research into Cannabis which would be corroborated as published papers in the scientific/research community.

Should have “, is now at an end” at end of paragraph.

Pax-Delta-Pan June 27, 2011

Indeed the BS never ends, opinions don’t count for crap when facts prove otherwise, but opinions seem to be presented as ‘professional’ and ‘expert’ judgements contradicting facts in research and actual cases which prove case in fact regards cannabis being anticarcinogenic and deemed more valid than what are facts.

Look below the surface, and i bet those attempting to contradict, are associated with those in the scientific community who have earned significant amounts by publishing books and consultancy for judicial proceedings and many very important reports for many organisations etc which their work hijacked and misled etc, who have engaged in falsified research funded by pharma corp’s and Alcohol industry so they continue to have wealth through monopoly etc, who have demonised Cannabis as medicament as much as a recreational substance much safer than Alcohol and know their reputations are suffering because the truth about cannabis is becoming common knowledge, so when research and cases representing what are truths and fact regards cannabis such as it being a potent anti carcinogen and can retard and even eradicate tumours etc, they come out of the woodwork and try to re-establish their erroneous BS as facts, because more and more are realising the era of prohibition allowed what are actually charlatans were allowed to prosper in career, reputation and status among the scientific community because they reinforced prohibition propaganda and were not questioned, such was the pitifully low amount of permitted research into Cannabis which would be corroborated as published papers in the scientific/research community.

Now that has changed, thanks to the United Nations, and a lot of cannabis research is steaming ahead, proving many who have written for the prohibitionists to be so wrong it’s ridiculous, which is slowly tearing reputations of those charlatans apart, this is one way they try to maintain or re-establish reputation and futile attempts to refute truth and facts.

They were happy enough to gain from prohibition BS, now time to pay the piper as science proves just how wrong they were and are and they are seen for what they are, intelligent people, yes, but charlatans who profited by creating prohibitionist scientific convention and consensus based on nonsense, not actual science and research, all a manipulation to reinforce political prohibition policy regards cannabis.

The game is up for them, they don’t like it, and we see releases such as this via the science platforms for papers and studies etc, and indeed on this Cancer Research UK website, which as we know, is full of inaccuracies prompted by the same aforementioned situation, as in truth and facts, cutting edge research now the U.N. shift in paradigm has allowed proper research, which incontrovertibly contradicts their anti cannabis positions, and more importantly, political prohibition policy in the UK, as all those people are now being proved completely wrong, moreso every month which passes, so it is no stretch to consider Cancer Research UK is being politically manipulated to corroborate political policy and position, as much as idiots in the field who have supported bunkum for donkeys years and do not like looking stupid as facts which contradict them come from the now abundant research happening these days regards cannabis and the anti carcinogenic properties of cannabinoids.

They will no doubt be considering, they should have progressed with more integrity in decades past, indeed, yes, too late now though, they’ve established their careers on utter nonsense, now truth with enforce a balance, their own faults and i’ve no sympathy whatsoever!!!

Humans are not Mice, no, but Tumour retardation and eradication in mice and curent research suggest those trailed in several medical treatment centres around the world have had successes treating cancers and Tunours with cannabinoids, has been proven via cannabinoid treatments, and it is no stretch whatsoever, that the little boy derived more benefit from the cannabis than the Chemo’, however much it cannot actually be proved either way in this specific case, it has been proven elsewhere around the world.

I can’t be bothered to find the papers and citations etc at the moment, but it’s published on the Internet, Cancer Research UK should really get their facts right and do some actual research themselves instead of relying on old positions they consider to still be valid, because they aren’t, things have changed and are still changing with increasing momentum regards cannabis, they are just making themselves look unprofessional and as much charlatans as bunkum prohibitionists ‘scientists’ whose research they rely on, who are Not some fringe, metascientific new age non recognised scientists as some would prefer to believe, but formally recognised eminent scientists and research bodies, now proving the case for cannabis and cannabinoids in cancer treatments!

PaxDeltaPan aka, Paul Lawrenson.

Sarah June 27, 2011

Ok. The whole point of this article was to clarify that we “don’t know” what cannabis did for the boy’s cancer. Yet you clearly state under the photo that cannabis can NOT cure cancer. But you don’t really know that, do you? I am also concerned that this article tries to encourage people to believe the myth that smoking cannabis can cause lung cancer. This has been proved through Dr. Tashkin’s studies at UCLA to be false. In fact, none of his subject who smoked ONLY marijuana developed cancer. The ones who smoked marijuana in conjunction with cigarettes were actually LESS LIKELY to develop the cancer that we know tobacco use can cause. This boy’s tumors have ceased to grow. I have met this child. He is healthy, interactive, and can play now. He is a normal toddler. He has not lost his ability to live normally due to debilitating chemo. He is not so ill that he cannot lift his little head from the pillow. Cannabis DOES induce PCD, or programmed cell death. It has been proven. Why is the UK choosing to ignore this evidence too? I would also agree that this is more about the patents than the patients. Please read this article from the Journal of Molecular Therapeutics on how cannabis has been shown to cause/enhance cell death:

Marijuana Compound Induces Cell Death In Hard-To-Treat Brain Cancer

January 20, 2011 – Madrid, Spain

Madrid, Spain: The combined administration of THC and the pharmaceutical agent temozolomide (TMZ) demonstrates strong anti-cancer activity in brain tumors resistant to conventional anti-cancer treatments, according to preclinical data published online in the journal Molecular Cancer Therapeutics.

Investigators at Complutense University in Spain assessed the anti-tumor activity of the cannabinoids THC and CBD (cannabidiol) in glioma xenografts (tissue grafts).

Authors reported that the administration of THC in combination with TMZ (the benchmark agent for the management of glioblastoma) “enhanced autophagy” (programmed cell death) in malignant tissue. The combined administration of THC, CBD, and TMZ “remarkably reduce[d] the growth of glioma xenografts … [and] produced a strong antitumoral action in both TMZ-sensitive and TMZ-resistant tumors.”

They concluded, “Altogether, our findings support that the combined administration of TMZ and cannabinoids could be therapeutically exploited for the management of GBM (gliobastoma multiforme).”

A 2006 pilot study published in the British Journal of Cancer reported that the intratumoral administration of THC was associated with reduced tumor cell proliferation in two of nine human subjects with GBM, which is highly resistant to conventional anti-cancer treatments.

Separate preclinical studies assessing the anti-cancer activity of cannabinoids and endocannabinoids indicate that the substances can inhibit the proliferation of various types of cancerous cells, including breast carcinoma, prostate carcinoma, colorectal carcinoma, gastric adenocarcinoma, skin carcinoma, leukemia cells, neuroblastoma, lung carcinoma, uterus carcinoma, thyroid epithelioma, pancreatic adenocarcinoma, cervical carcinoma, oral cancerbiliary tract cancer (cholangiocarcinoma), and lymphoma.

For more information, please contact Paul Armentano, NORML Deputy Director, at: Full text of the study, “A Combined Preclinical Therapy of Cannabinoids and Temozolomide against Glioma,” appears in the journal Molecular Cancer Therapeutics.

Enrique Doubleglazias June 20, 2011

Come on Cancer Research – you are badly loosing this debate, it is painful to watch and you guys are ment to be against people suffering……….

Lindsay Butler May 28, 2011

Just want to apologise for the totally stupid math I displayed above, not really sure how I worked that out.

Interesting to see the level of opinion on this. The trouble with research is there is always some other research to say the something different.

What is clear though is the fact that Cancer Research does not think Cannabis as a realistic cure, and that no robust (even though they did some) evidence supports the case for cannabis as a cure.

Arguments on pure, or modified or legal status are just a smokescreen to avoid the issue. But what deeply worries me is why is Cancer Research trying to avoid a potential cure? A cure that could be grown at home, that could empower people and free the state of a sizeable medical bill.

Peter Reynolds May 28, 2011

Famously, when the US National Cancer Institute recently added cannabis as a treatment for cancer on its website, a few days later it was taken down.

Now, Freedom Of Information requests have shown that this was under pressure from the federal government.

I’m not a conspiracy theorist but it is manifestly true that the establishment wishes to suppress the truth about cannabis as a cure for cancer.

Matthew Sands May 24, 2011

Cancer research UK admit that science has proven that cannabis kills cancer cells and does so with out damage to healthy cells, they admit that it could be a treatment (but only support it’s use in synthetic form). But if cannabis kills cancer (as is now proven) then doesn’t that qualify it as atleast a potential cure? Also why haven’t cancer Research UK responded regarding Sativex, which as Peter Reynolds pointed out, is natural cannabis sold at a massively inflated price.

Matthew Sands May 24, 2011

Although I think it is clear Cancer Research UK is intentionally under stating the anti cancer effect of cannabis. If cannabis kills cancer (which is now proven) then why are Cancer Research UK not atleast championing cannabis as a medicine for “treatment” of cancer, even if Cancer Research UK won’t except Cannabis as a potential cure (despite the increasing evidence showing that it is a potential cure). By your own admission, cannabis is proven to kill cancer without causing any harm to healthy cells. By supporting synthetic cannabinoid research but ignoring natural cannabis, Cancer Research UK is showing a disgraceful disregard for cancer patients.

Kat Arney May 24, 2011

Hi Jim,
You’ll see from our posts this is exactly what we’ve been pointing out. Cannabinoid chemicals have indeed shown potential to be useful for treating cancer, when used in a purified and controlled way. For example,Cancer Research UK has funded scientists investigating cannabinoids for bowel cancer.

However, we must point out that there is no solid scientific evidence that using unprocessed herbal cannabis, resin or cannabis oil can itself treat the disease. This is quite aside from the huge variability in the concentration of cannabinoids in such products, the presence of other chemicals, the potential side effects, and the legal issues.


Jim May 23, 2011

… “there’s no robust scientific evidence to show that cannabis or cannabis oil can successfully treat cancer”.

Funny, as I’ve read dozens of scientific papers showing that cannabinoids encourage apoptosis in cancerous cells. Cure cancer? No. TREAT cancer? Yes. Absolutely.

Matthew Sands May 13, 2011

cannabis is anti pshycotic and there is no genuine evidence linking cannabis use to mental illness. As Peter said, the best they can give is associative “evidence” which actually shows greater corelation between tobbacco smoking (and alcohol consumption for that matter). Experts on mental illness agree that there is no real evidence to suggest cannabis causes things like schizophrenia, infact most researchers will tell you there is much more evidence to suggest cannabis can be helpful for people who suffer such conditions.
So much lies are said about cannabis. It has been accussed of causing cancer when the truth is it can cure it. It has been accussed of causing mental illness when the truth is that it’s far more likely a useful medicine for such conditions.
The media and Cancer Research UK should be made accountable for their false statements

Lindsay Butler May 12, 2011

There lack of research in to cannabis as a cure is what I am unhappy about. This post is related to cannabis so what do you expect? Comments complimenting cancer research for being a £300 million (it is nearer £400) a year charity that does what it should. (If doing low budget research in to possible NEW cures is what Cancer Research should do)

Consider that around 300,000 people were diagnosed with cancer in 2008, Cancer research probably made around made a £300 million “profit”. £1 million worth of research per person. Amazing.

Peter Reynolds May 12, 2011

By the latest research, the risk of developing psychosis or schizophrenia as a result of using cannabis is at least one in 7500 and perhaps as little as one in 30000.

Professor Glyn Lewis of the University Of Bristol reviewed all the published evidence on the subject in 2009 and says that 96% of people can use cannabis without any risk of psychosis at all and in the remaining 4% the risk is statistically tiny. Even if direct causation of schizophrenia by cannabis was accepted (which is clearly not proven) then on Prof. Lewis’ figures that would amount to approximately 800 additional cases per annum. Based on the Home Office’s figure of six million regular cannabis users that amounts to a risk of one in 7500. In fact, while there is evidence of some correlation between cannabis use and mental health problems there is none of causation. There is, in fact, much stronger evidence of correlation between tobacco smoking and mental health (more than 90% of those diagnosed with schizophrenia smoke tobacco) but no one is claiming that tobacco causes schizophrenia.

As well as the University of Bristol study referred to above, studies published in US journal “Schizophrenia Research” in 2010 indicate that “…marijuana is unlikely to instigate incidences of schizophrenia in the general population, that cannabis use among patients with the disease is associated with higher cognitive function, and that at least some schizophrenics find subjective relief from symptoms of the illness by using pot”.

Furthermore, in Britain in 2009, the ACMD commissioned a study by Keele University into the trends in schizophrenia specifically to test the claims in the media of a link between it and cannabis. It looked at almost 600,000 patients and concluded that “..the incidence and prevalence of schizophrenia and psychoses were either stable or declining” despite alleged increased use of allegedly more potent cannabis.