Cannabis users are 40 per cent more likely to develop a psychotic illness than
non-users, a study has found.
Heavy users are more than twice as likely to suffer mental illness, according
to a group of British academics, who calculate that about one in seven cases
of conditions such as schizophrenia is caused by cannabis.
The warnings come as the Prime Minister and the Home Secretary signalled that
the “softly softly” era for cannabis may be coming to an end.
Gordon Brown said last week that the Home Office would be consulting on
whether it had been right to downgrade cannabis from a Class B to a Class C
drug in 2004. Jacqui Smith, the Home Secretary, is to ask the Advisory
Council on the Misuse of Drugs to review the evidence.
The paper, published in The Lancet, is written by a group of seven
psychiatrists and psychologists from Bristol, Cardiff, London and Cambridge.
They have pooled the findings from 35 studies in a number of countries,
including the United States, Germany, the Netherlands, Sweden and Britain,
and concluded that there is “a consistent association between cannabis use
and psychotic symptoms, including disabling psychotic disorders”.
They admit that they cannot be certain that the association means that there
is a simple cause and effect, but say that policymakers “need to provide the
public with advice about this widely used drug”. They go on: “We believe
there is now enough evidence to inform people that using cannabis could
increase their risk of developing a psychotic illness later in life.”
As well as looking at psychotic illness, they looked for evidence that
cannabis could cause affective disorders such as depression, anxiety and
suicidal thoughts. Almost all the studies point towards an increased
incidence of such disorders. The evidence is less strong, the writers say,
but is still of concern.
The study was welcomed by many experts, but others counselled caution. Leslie
Iverson, of the University of Oxford, a member of the advisory council,
said: “Despite a thorough review the authors admit that there is no
conclusive evidence that cannabis use causes psychotic illness. Their
prediction that 14 per cent of psychotic outcomes in young adults in the UK
may be due to cannabis use is not supported by the fact that the incidence
of schizophrenia has not shown any significant change in the past 30 years.”
But Robin Murray, of the Institute of Psychiatry at King’s College London,
called it “a very competent and conservative assessment of what research
studies tell us about the relationship between cannabis and psychiatric
disorders”.
He said that the risk could be even higher then the authors had estimated,
because the cannabis available today was stronger than in the past. “This
report cannot tell us whether the risk is higher with the use of the
skunk-like preparations which are now widely available, and which contain a
higher percentage of tetrahydrocannabinol,” he said. “My own experience
suggests to me that the risk with skunk is higher. Therefore, their estimate
that 14 per cent of cases of schizophrenia in the UK are due to cannabis is
now probably an understatement.”
Martin Barnes, chief executive of Drugscope and also a member of the council,
said: “Cannabis is not harmless, and although it has been known for some
time that the drug can worsen existing mental health problems, it may also
trigger the onset of problems in some people.”
“The challenge is to ensure that information on cannabis use and the
associated risks is understood by teachers and health professionals working
with young people and conveyed in ways that young people will listen to.
Since reclassification, cannabis use has continued to fall. We need to make
sure this trend continues.”
Marjorie Wallace, chief executive of the mental health charity SANE, said:
“The Lancet report justifies SANE’s campaign that downgrading
a substance with such known dangers masked the mounting evidence of direct
links between the use of cannabis and later psychotic illness. The debate
about classification should not founder on statistics but take into account
the potential damage to hundreds of people who without cannabis would not
develop mental illness.
“While the majority can take the drug with no mind-altering effects, it is
estimated that 10 per cent are at risk. You only need to see one person
whose mind has been altered and life irreparably damaged, or talk to their
family, to realise that the headlines are not scaremongering but reflect a
daily, and preventable, tragedy.”
Martin Blakeborough, director of the Kaleidescope Project and a member of the
council, said that it would be a waste of public money for the same panel,
with the same evidence, to review the issue again. “There is significant
danger in reviewing cannabis again, as it takes experts’ minds off more
important issues. Classification itself, although important, is not as
urgent as the increasing epidemic of hepatitis B and C among drug users and
the wider community, or the increase of stimulant drugs in our community.”
<<>> "Cannabis should be Legal. Just because politicians don't use it, it doesn't mean the rest of us don't." <<>>
/
Paul, Grimsby, England
Im a 29 year old male who has smoked cannabis for 15 years the past 7/8 years ive been smoking it from the minute i wake up to the time i go to bed, all day I am high. i feel the effects of it recemtly, i blank out and have missing hours in my day, i cant function without it, i dont feel normal unless ive had a few bong hits then I can start my day. I know its not good but can stop now. my mind is lost, Im looking thru empty eyes and its so hard to get help from some one who understands. people say its just pot....you can just stop smoking it but its not that easy....trust me. I wish I could show people the real effects of this plant.
Dean Williams, colchester, essex
What was the question again?
will, Reggio Emilia, Italy
I read that approximatly 1/1000 people will develope phycosis in their life. This means that a 40% increase (given from excessive cannabis use) only makes the number of people up to 1.4/1000. Thats a 0.14% chance of becoming mentally ill for a heavy user. 0.14% certainly isnt 40%; the government and news twist statistics like this to 'prove' points to further their own agenda.
Richard Hayes, Wolverhampton,
The Lancet UK medical journal's studies said that 90% of schitzophrenia sufferers are tobacco smokers, so why isnt tobacco being treated as a possible factor?
oh yes, thats right, because the government tax us for tobacco.
Billy, Essex,
I think its important to put this in perspective. Some studies have indicated significantly higher levels of risk exist for alcohol (in causing schizophrenia). People should be informed of the risk they are taking. But any sane analysis of the risks would result in cannabis being legalised.
Sure cannabis can be addictive, it can cause cancer, it can destabilize one mentally. But in all of these faults it is completely out done by tobacco and alcohol.
Barnaby Dawson, London, UK
The Egg or the Chicken first? Did the drug cause the problems or were they underlying and the drug used unconsciously in an attempt to feel better at very early stages, which it probably didn't and actually led to even less control?Regarding Ben's point, isn't it also true that alcoholism generally also reflects some wider problems? Or , for that matter, eating disorders in general? Which are proven to cause a type of Diabetes? Where is the difference?
I wish all the addictive trends were analysed together and summarized once and for all.
It is not a problem of one or two particular drugs at the bottom of the issue, but of Human Nature.
Elise, Oxford,
The tragedy is that a lot of well-meaning people, some of them so-called 'experts' have staked their reputations on a short-term judgment of the risks of cannabis, without taking account of the long-term view, because the long-term was still an unknown future in the early and mid-nineties. Many of these people will now continue to argue that the dangers of cannabis are no worse than alcohol or cigarettes. The irony is that at a time when the state has imposed draconian restrictions on smoking in public places, it appears so impotent in cracking down on drug abuse by the young. Pace all the sophisticates and their liberal views on drugs, I ask what will this mean for today's teenage dopers when they are old?
the elderly.
Maggie, Crouch End,
I completely agree with this article, and I am tired of people saying cannabis is not addictive. I have seen the effect that cannabis has on people's lives when smoked reguarly, and it doesn't just affect the user but the people who care about the user as well. Stop the soft approach towards cannabis, there should be tougher laws. For starters there is no breath test for people driving under the influence of the drug as there is with alcohol and I think this is dangerous.
e, london,
Drink a quart of milk every day, use butter liberally, eat cheese as much as you want, eat lots of red meat, always have a couple of glasses of wine with your meals.
And don't forget to book an appointment with a cardiologist!
The moral being that too much of ANYTHING will be bad for you over the long run.
Alain, Montreal, Canada
i'm a cannabis user, have been smoking it for over ten years. while i am not naive enough to stand here and say it is not addictive and harmless, it is far less addictive and harmless than alcohol, which our government not only allow us to consume, but profit greatly from. sure, there are long term effects of using it. but at least my liver and kidneys are fine. when the government stop burning fossil fuels and polluting my breathing air, then maybe they can patronise me about the dangers of what i do.
matt, kidderminster, uk
As far as I'm aware, there has been one reported death linked to Cannabis, this was when a bud/seed exploded and entered the users eyeball.
Alcohol kills thousands, but due to the revenue government reap from that.......Nothing.
I was once told by a Highly ranked police officer, that they would rather raid a party with 100 smokers, than a Pub with 4 drinkers.
Just something to think about.
The Ledge, London, UK
Geoff M - have you ever been to the Caribbean? Cannabis use there is not as rife as you might think.
As for your opinion that cannabis-users are losers or have an inability to cope, I could quite easily say the same of people who share your opinion, but of course that would be purely subjective.
There are many people (particularly Times readers) such as Chris in Perpignan who look down from their high horses, when in fact they have no experience of the drug, or any other drug (except the legal ones). The only reason cannabis is illegal is because of the oil industry, as it recognised many many years ago how many products made from hemp it could replace, and so began a coordinated campaign to demonise cannabis, which comes from the same plant.
As ever, it is the most ignorant who are the most opinionated.
As the author notes, there is no evidence of a cause and effect relationship, and it could well just be correlation.
Mary Jane, Birmingham,
cann a bis in my view is not a cause of mental illness its with a certain amount of people a symptom.
The mental state of people depends on many things not just one aspect such as cannabis use or whatever .Drugs do mess with your body education not prohibition works and maybe everybody should have free or very cheap access to good psychologists so they understand why they do the things they do and can be more self governing instead of being fed sxxt by a group of egoistical politicians who will use all types of scaremongering or other tactics to control the masses and win empty meaningless applause .Alcohol kills and tobbacco if the government wants to do something usefull help the people become free thinking and free living then they might be happier and use drugs moderately and realise governments have other motives other than seeming to be interested in your health they wouldnt follaw that way as autonomy isnt easily controlled.
adrian, marseille, france
I'm not surprised by these findings. Many of my friends have been smoking cannabis since their late teens. Their excuse was that it was not addictive and less harmful than a cigarette. We are now in our early thirties and my friends still smoke the stuff, which makes me question if it is addictive? They have also developed the Doh factor. Bright guys ten years ago but it now takes them twice as long to process information or a simple question.
Whilst there were no symptoms in the early years I'm glad I didn't touch the stuff.
Paul, London,
Come it's simple. Anything God made is not a drug . Drugs have undregone chemicall synthsis.
jerone, kosciusko,
this government allows us to take 'man made drugs' that lead to a lot more damage than cannabis causes - see article below regarding the diabetes drugs that cause heart failure. cannabis should be in the same category as alcohol - end of story.
rachel, Cambridge, UK
I would have thought that Brit's, as Europeans, were less provincial than Americans, and hopefully more able to spot propaganda posing as scientific research. Orwell shudders in his crypt.
The most damaging aspect of propaganda and bad laws is that the young, always quick to spot a red herring, then presume the opposite must be true. In this case they see dishonest or misinformed authorities state that cannabis and the like is "horribly dangerous", and then conclude these drugs must be completely safe and perhaps even beneficial. Thus the "scientific studies" showing that government anti-drug programs in schools effectively promote drug use in the young. As The Bard put it: "methinks he doth protest too much."
Did British society learn nothing from the Beatles?
Levi Gomez, Denver, Colorado, USA
Why do the "facts" regarding cannabis use & its effects change every week?
each time theres a higher & higher risk of developing a mental illness, its like if their first claim doesnt get a reaction, just keep making the stats higher and higher until it does.
fact is, 99.9% of cannabis users have never had any ill-effects or even know of anybody who has, so most cannabis users simply cannot relate or even believe these outlandish claims.
surely you would think Amsterdam would be the measuring stick regarding cannabis use? nope, because Amsterdam doesnt have a higher percentage of people suffering from mental illness, and that wouldnt fit into the Government's propaganda agenda
Billy, Essex,
Where two events are statistically connected, in this case Cannabis use and schizophrenia, logically there are three causal possibilities:-
A causes B
B causes A
A and B are caused by another common factor.
The research data published above clearly discounts the first that cannabis CAUSES mental illness as, while cannabis use and dosages have increased substantially, schizophrenia has not.
It remains possible that schizophrenics (and potential schizophrenics) are particularly prone to abuse cannabis in the first place, and therefore that B causes A
In any way the third option is still the overwhelming favourite unless any increase in proportion to dosage is demonstrated.
Your headline is clearly false and is the opposite of the findings. It should read "Those with psychotic illnesses are at great risk of abusing cannabis"
Brian Vallance, LEFKIMMI, Greece
"If this were true, which I don't believe it personally"
In my experience it's true. I know two people who have become complete nutcases through heavy canabis use. But it's no worse than heavy smoking or heavy drinking or, as alex says, eating too much. It all has negative side-effects.
starling, Lancaster,
As a sufferer of a psychotic illness I can say that cannabis worsened my symptoms when I was going through a particularly bad patch, but what is often forgotten is that there exists another drug in cannabis, cannabinol, which produces a calming effect similar to the many antipsychotic drugs available, with less side effects and none of the paranoia and high associated with the THC. Why is there no research being done on this substance, it could save the taxpayer millions.
Mr. Smith, Kilkenny, Ireland
How many people that want to smioke canabis refrain from doing so because of it's legal classification?
Legalise and you can study it properly. The statistics in here tell us nothing.. 10 per cent are at risk? 10 per cent of what - heavy users? occasional users? weekend users? long term / short term users?
I imagine it is saying that 10 per cent of heavy users run the risk. Which is a little like saying x% of alcoholics damage their liver i think.
Everything in moderation and all that!
Adam, Edinburgh, UK
When I was younger I used a veritable cocktail of drugs and believe this may have something to do with my present psychological state. I believe that I hear my name everyday on the televisionand radio and that people in the street, on the trams, in the shops and at work are all making derogatory comments to and about me, fuelled by comments from the media.
I am intelligent and aware enough to know that this is not only impossible and illogical, but is also the first sign of paranoid-schizophrenia.
Every day is like a living hell full of 'criticisms, put-downs and ridicule' that my self-esteem and belief in self worth has taken a severe battering.
I pride myself on the fact that I try not to let all this get me down and try to lead a 'normal' life, but it is very difficult and tiring, and a few times I have felt close to breakdown, but I always pull through.
Let this be a warning to anyone using drugs these days, they can have far-reaching consequences.They were fun at the time though!
Elliott, Cheltenham,
In answer to Ben of Walligford's question. I wouls estimate that the number of people who use alcohol and develop alcoholism, is greater than those who do not use alcohol. Of that I am fairly confident.
Carl Teper, Rome, Italy
Maybe people who are prone to developing conditions such as depression are more likely to use cannabis to make them feel better? The link cannot be described as cause and effect, as smoking cannabis can relax you and make you not worrying about your real problems...
Smokey McPot, Essex, Uk
I would say after 40 years of medical experience that the argument could be inverted ... maybe canabbis allows people, sensitive people in particular, to cope with an increasingly violent, heated up world.
Jean Paul Lenoir MD, Buenos Aires, Argentina
Surely this whole article is rendered almost meaningless by the statement that the study "is not supported by the fact that the incidence of schizophrenia has not shown any significant change in the past 30 years.†Given that the level of cannabis consumption in the UK is some 2-300% higher than it was 30 years ago, being far more widespread, and that a great part of the cannabis now consumed appears to be the more potent "skunk" form, any numerate epidemiologist can see that there is a flaw.
It is fascinating to note that a respected psychologist has experimented, as Robin Murray admits: “My own experience suggests to me that the risk with skunk is higher...." However if he is partaking, I am disinclined to accept his pronouncements as lacking the academic rigour that confers authority.
Marjorie Wallace says: "The debate about classification should not founder on statistics...." Should we disregard science and evidence and base policy on hysteria and vested interest then?
Kidd Garrett, Bristol, UK
There is something obscene about a Government of ex=pot smokers trying to re-classify cannabis, whilst at the same time letting us all drown in a sea of alcohol
Vin Adamswood, Scartho, Lincs
Is this sudden fuss about cannabis anything to do with the fact that Sativex is about to become available from the NHS?
RW , Yorkshire,
Opinions contained within the article are divided, more research is clearly needed.
The use of cannabis is likely to be even more widespread than currently understood - I think that this would create a much greater mental health 'spike'?
Statistics are enormously misleading - 'Hundreds more people have died from wrongly precribed drugs, compared to those from smoking cannabis' - for example
Reasons why more people might be depressed - fool governments who engage in war against people that don't deserve it, a million people take to the streets in protest who are then ignored, governments that pile on mountains of legislation, to the point where I need to consult my solicitor before taking the 'health risk' of getting out of bed, governments that can't prioritise what isssues are really important.
From the other side of the coin, Gordon and his mob are on another planet - do as I say, not as I do(pe)
Bill Bird, Wallasey, Wirral
THis is a much more complex issue than it at first seems I notice there was no headlines when a study in may showed another chemical component to cannabis, cannabidinol (CBD), actually inhibits and suppresses psychotic symptoms in people suffering from them. CBD is so good at suppressing psychotic symptoms that it proved to be more effective than any of the major anti-psychotics currently prescribed by doctors.
Professor Jim van Os suggests a solution: legal cannabis could be easily grown and marketed with high CBD levels, ending the psychotic effect. Indeed, such a drug would actually be helpful for psychotics to smoke. Obviously, it's impossible to do this while cannabis remains in the hands of organised crime syndicates - a certainty under prohibition. So it is actually more accurate to say cannabis prohibition causes cannabis psychosis, and legalisation would end it.
John, Sheffield, UK
This information doesn't seem to bother a lot of MPs. They have either smoked it themselves or have stated that it should not be re-classified. I heard one Labour MP on the radio earlier who said that these statistics don't mean much in the wider scheme of things. Now it might be me but 800,000 people exhibiting psychotic behaviour, with Doctors now saying that a lot of them may be having problems because of cannabis consumption, doesn't seem like a minor problem to me. Then again, who am I to be bothered about someone hearing voices attacking me in the street?
judy, Liverpool, england
According to a US study I read, 4.7 percent of adults report having some problem with alcohol abuse and 3.8 percent were alcohol-dependent. But how is that relevant? It wouldn't feasible to attempt to ban alcohol because 90%+ of the population use it, so whyshould that be a benchmark against which to determine whether any other substance should be made legal? We know cannabis is dangerous (as shown again by this further research) - the vast majority of people don't generally use the stuff - so let's keep up the pressure and while we'll probably never entirely eradicate it, at least we can obstruct the supply and thereby minimise the harm it does. A programme of youth education as to its harm as well as reclassifying it as a Class B would be a good start.
Bisonex, S Yorks, UK
what percentage of people who drink become violent? It is a common to see drunks fighting in any city centre on a friday night..
A psychoactive drug is bad for people with mental health issues? Also in this weeks news, fatty food makes you fat.
alex c, bristol,
A key paragraph from this article needs highlighting
“Despite a thorough review the authors admit that there is no conclusive evidence that cannabis use causes psychotic illness. Their prediction that 14 per cent of psychotic outcomes in young adults in the UK may be due to cannabis use is not supported by the fact that the incidence of schizophrenia has not shown any significant change in the past 30 years.â€
AO, Southampton,
If this were true, which I don't believe it personally, then Legalisation ,would help those few people who may have trouble with cannabis.
Hard drugs seem to have taken a back seat since our change of PM. not a good start, or is it just spin, so we don't notice our binge drinking culture, that could use healthier competition in the form of cannabis cafes.
Cigarettes are our biggest killer , they can talk about reclassification of cannabis , however maybe we should talk of classifying alcohol and nicotine, to save our youths developing brains.
Winston Matthews, Horley ,, Surrey
This is not news - these facts have been around for a long time.
Why do you think that Afro-Caribeans are about four times more likely to suffer paranoia and schitzophrenia than indiginous Brits?
Everyone I know who smokes the stuff is either a complete loser or experiences problems coping with work and life.
Geoff M, Bromsgrove, England
Ben,
Probably around 1% in UK by a rough calculation. We have about 300,000 alcoholics, and the vast majority of the adult UK population take alcohol. One other point about regular cannabis smoking is that it may also be far more likely to cause cancers in young people than tobacco. It may also exacerbate the effects of tobacco smoking, as can heavy alcohol usage. There is limited evidence on this because people do not always admit to using cannabis.
Trevor, London, UK
Cannabis is the chav drug of choice, and instead of ridding this country of the social ills that produce an unemployed underclass, Brown wants to tackle a cosmetic feature--the use of cannabis--because it will make the middle classes feel better. At the same time, he wants to LOWER the minimum wage in the poorest parts of the UK!
Michael, Nottingham, Nottinghamshire
THIS IS NOT NEWS!! Aren't people getting bored of this story being churned out every couple of months? Yes, cannabis smokers are taking huge risk of psychotic illness. Question is, what is this incompentant Governamne t going to do about it.
Alex, London,
So, there is no eveidence but the 'experts' have drawn the same conclusions as they have in the past. Just as the government start to discuss reclassifcation (again).
This is a typcial of the establishment making conclusions that fit their model (and their paymasters curent requirement )and not the facts. No, it is not good for you (unless you are in pain), but is it any worse for you than alcohol, nicotine or an anti depressant?
There are many evil things that exist in this world, cannabis sits way down the list of such things and to pretend any different is naive scaremongering.
The drug is used by hundreds of thousands without problem. That is a fact.
Catim, London,
Why does no-one ever look at the diseases and problems that alcohol causes, what about alcohol addiction? That problem is absolutely rife, but because it's legal - it's perfectly ok. Will it ever be a class B drug like it should be? No, because too many politicians get slaughtered everynight. The adverts on this very page all refer to drug addictions, surely alcohol addiction is just as bad, if not worse.
Which is worse really alcohol or cannabis? Or are they both as bad?
Amanda Walker, Leeds, West Yorkshire
40% more likely than ......... ? Another unpardonable journalistic solecism. Everyone knows cannabis, or any such substance is bad for the developing brain (ie up to about age 21), so why not concentrate our efforts on preventing the young from getting hold of them, (life imprisonment for supplying to the young) and let adults make up their own minds (as with alcohol).
John Ledbury, Kings Lynn, England
Once one has read beyond the headline, it is clear the issue is multifaceted and more complex. Why do researchers not look into the question of whether those predisposed to try drugs in the first place are not more likely to develop psychiatric problems compared to those who have the resolve / strength of character to avoid such experiments?
Chris, Perpignan, France
How can we expect any sense from the Advisory Council on the Misuse of Drugs when it is packed with people who are soft on cannabis? There are strong suspicions that these people are themselves, or have been, cannabis users. It's like expecting turkeys to vote for Christmas.
Terry Hamblin, Bournemouth, UK
If alcohol and tobacco were to be classified under current drug banding they would both be class A or B.
Rupert, Launceston, Cornwall
Is cannabis use falling. Really? There are grounds for thinking that cannabis use in Britain has widened & deepened. By that I mean "first use" is typically earlier, use is typically more frequent and use typically goes on for longer. There are more ,regular & older users than was the case 15 years ago. Martin Barnes is in my opinion selectively quoting and spinning the evidence to defend the historical position of DrugScope. Martin Barnes and his predeccesor , together with associates involved with the European drug legalisation movement, have been substantially (amazingly!) funded from public funds. Parents & tax payers concerned about Britain's worsening drug using culture, surely deserve better.
David Raynes, Radstock, UK
What percentage of people who use alcohol develop alcoholism?
Ben, Wallingford, UK
So - what most of us know, that if you take away the illegality factor, it is then less 'cool', has been proven true (and use has consequently dropped). So - I know what we'll do - let's reverse that, let's make it cool again and get more people using it. Yeah, let's play into the hands of the criminals, ignore the lessons of prohibition and let's invest in crime again (because that's what it means in reality).
Gordon's looking for some quick wins, so let's pretend the we're going to make a difference by locking up a few more people - no matter if cred & use go up again!
If the government really wanted to make a difference, they would be fighting the harm caused by alcohol. What percentage of the young population drink? And of those what percentage will end up with health problems, kill others through drink/driving, or will inflict violence on others? How many "daily preventable tragedies there Marjorie? Not so soft a target is it? Too many vested interests to fight on that one!
CW, Warwick, UK