(Combined) Does Smoking Cannabis Increase Mental Illness Danger by 40%?

By BackToBasics · Jul 27, 2007 · ·
  1. BackToBasics
    [h1]Smoking just one cannabis joint raises danger of mental illness by 40%[/h1]
    By FIONA MACRAE and EMILY ANDREWS - Last updated at 23:57pm on 26th July 2007
    [​IMG] Comments
    potREX2103_228x339.jpg There are great risks in smoking cannabis, a new report has revealed

    A single joint of cannabis raises the risk of schizophrenia by more than 40 per cent, a disturbing study warns.

    The Government-commissioned report has also found that taking the drug regularly more than doubles the risk of serious mental illness.
    Overall, cannabis could be to blame for one in seven cases of schizophrenia and other life-shattering mental illness, the Lancet reports.

    The grim statistics - the latest to link teenage cannabis use with mental illness in later life - come only days after Gordon Brown ordered a review of the decision to downgrade cannabis to class C, the least serious category.

    The Prime Minister is said to have a 'personal instinct' that the change should be reversed, with more arrests and stiffer penalties for users.

    Cannabis has been implicated in a string of vicious killings, including the recent stabbing of fashion designer Lucy Braham.
    The authors of the latest study, the most comprehensive of its kind and commissioned by the Department of Health, said: 'Policymakers need to provide the public with advice about this widely-used drug.
    '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.'

    The analysis does not look at the age at which schizophrenia is likely to develop. However, previous studies have shown that smoking the drug as a teenager raises the risk of developing schizophrenia in one's twenties or thirties.

    The researchers, from four British universities, analysed the results of 35 studies into cannabis use from around the world. This suggested that trying cannabis only once was enough to raise the risk of schizophrenia by 41 per cent.

    At greatest risk, however, were heavy users, with those who took cannabis over 100 times having more than double the risk of those who never touched the drug.

    With up to 40 per cent of teenagers and young adults in the UK believed to have tried cannabis, the researchers estimate that the drug could be behind 14 per cent of cases of schizophrenia and other psychotic illnesses.
    'Although individual lifetime risk of chronic psychotic disorders such as schizophrenia, even in people who use cannabis regularly, is likely to be low - less than three per cent - cannabis use can be expected to have a substantial effect on psychotic disorders at a population level because exposure to this drug is so common.'

    Cardiff University researcher Dr Stanley Zammit added: 'Even if cannabis does cause an increased risk of developing psychosis, most people who use cannabis will not develop such an illness.
    'Nevertheless, we would still advise people to avoid or limit their use of this drug, especially if they start to develop any mental health symptoms, or if they have relatives with psychotic illnesses.'
    In an accompanying editorial in the Lancet, Dutch psychiatrists said the focus on heroin, cocaine and other Class A drugs meant the dangers of cannabis had been overlooked.

    'In the public debate, cannabis has been considered a more or less harmless drug compared with alcohol, central stimulants and opioids.
    'However, the potential long-term hazardous effects of cannabis with regard to psychosis seem to have been overlooked, and there is a need to warn the public of these dangers, as well as to establish a treatment to help young frequent cannabis users.'
    Previous studies have shown a clear link between cannabis use in the teenage years and mental illness in later life.
    Research completed by leading psychiatrist Professor Robin Murray in 2005 showed that those who smoked the drug regularly at 18 were 1.6 times more likely to suffer serious psychiatric problems, including schizophrenia, by their mid-20s.

    For those who were regular users at 15, the stakes were even higher, with their risk of mental illness by the age of 26 being 4.5 times greater than normal.
    It is thought that, used during teenage years, the drug can cause permanent damage to the developing brain.

    Professor Robin Murray, of the Institute of Psychiatry in London, warned yesterday that the risks were likely to be heightened by the increasing use of powerful skunk cannabis.
    'My own experience suggest 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.'
    Marjorie Wallace, chief executive of the mental health charity SANE, said: 'This analysis should act as a serious warning of the dangers of regular or heavy cannabis use, doubling the risk of developing schizophrenia - a condition in which a person may hear voices and experience strange thoughts and paranoid delusions.

    '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.'
    However, others questioned the link, pointing out there has been little change in rates of schizophrenia in recent years despite the rise in cannabis use and the increasing strength of the drug. _____________________________________________________________________ Three heavy drug users and their horrific killings:
    jaggsDM2707_228x288.jpg Prolific cannabis user and killer: William Jaggs

    William Jaggs, a 23-year-old Oxford University student and prolific cannabis user, stabbed fashion designer Lucy Braham 66 times at her home near Harrow, the public school in North-West London.

    The paranoid schizophrenic was found covered in blood beside Lucy's body, having plunged the knife into his own chest last September.
    The former Harrow pupil, whose father is a teacher at the school, started using drugs when he was 14, moving on from cannabis to cocaine.
    He was sent to Broadmoor secure hospital this month for an unlimited period after admitting manslaughter on the grounds of diminished responsibility.

    cazalyDM2707_228x288.jpg Drug-crazed killer: Richard Cazaly

    Drug-crazed drifter Richard Cazaly is believed to have stabbed pregnant Abigail Witchalls in Surrey, in April 2005.

    Cazaly, 23, who killed himself five days after the stabbing, had a history of heavy drug use dating back at least four years.
    His girlfriend, Vanessa MacKenzie, told police both she and Cazaly were regular cannabis users, smoking 'a couple of joints a day'.
    Surrey police said Cazaly became psychotic and violent as a result of long-term abuse of drugs and the alcohol he had consumed on the day of the random stabbing.
    Miraculously, Mrs Witchalls and her unborn baby survived the attack. Her young son - who she was pushing in a pram when she was set upon by Cazaly - was unhurt.

    PalmerDM2707_228x288.jpg Mind warped by smoking skunk: Thomas Palmer

    Son of a nurse at Broadmoor Thomas Palmer butchered two of his friends during a woodland walk after his mind was warped by smoking skunk - a particularly potent form of cannabis.
    Then aged 18, he virtually beheaded 16-year-old Steven Bayliss and repeatedly stabbed Nuttawut Nadauld, 14, near their homes in Wokingham, Berkshire in September 2005.
    Palmer had started using the drug at 14. He told doctors he had not been smoking on the day of the killings but admitted to using skunk regularly in the weeks before the brutal attack. In March this year, he was given a minimum 20 years in prison for the double murder.

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  1. Coconut
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    This is silly. Everyone knows psychoactive drugs such as cannabis can trigger inert, underlying psychosis. It's easily for the government/media propaganda machine to put the blame on cannabis for this, when in fact they were probably psychotic all along. If you're fucked up in the head, even if you don't know it, dosing yourself with THC is just going to make it worse.
  2. Nagognog2
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    How about caffeine? They won't give you a cup of coffee in the nuthouse. It's said to trigger, or aggravate, psychotic symptoms. I wonder what percentage of schizophrenics drank coffee. Even once.
  3. Lunar Loops
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    Typical Daily Mail style journalism. Find a few cases where killers have smoked cannabis and then link the two, et voila here we have a great story and right wing propoganda piece all rolled (pardon the pun) into one ridiculous story. Psychotic individuals murder regardless of what they have or have not been taking, they may have all been drinking in weeks prior to the killing, should we blame alcohol for their actions?

    This story appears prominently in nearly every UK newspaper today and SWIS heard it on the radio over here in Ireland today on the way to work. The propoganda war is nearly over and reclassification in the UK is virtually assured. One point they seem to fail to realise is that it will not make a blind bit of difference. Just as SWIS was underwhelmed by the move to downgrade (made little difference to those who used the drug), he is similarly underwhelmed by this new move to reclassify. People who wish to use the drug still will. In fact studies show that cannabis use in the UK has actually dropped since downgrading. Of course those in power have to be seen to be doing something to appease the middle England voter (not to mention those with whom they have a 'special relationship' across the Atlantic).

    What annoys SWIS is the fact that it also influences the views of those who know absolutely nothing about the drug and many of those will believe the type of gutter journalism shown by the Daily Mail. Cannabis smokers turn into crazed killers.....reefer madness indeed.

    Just as an aside, here is the abstract from The Lancet. Please read carefully.....note that it does not make anything like as compelling reading as the stories that appear in the press. Take a study and apply some spin indeed.......

    Cannabis use and risk of psychotic or affective mental health outcomes: a systematic review

    Background Whether cannabis can cause psychotic or affective symptoms that persist beyond transient intoxication is unclear. We systematically reviewed the evidence pertaining to cannabis use and occurrence of psychotic or affective mental health outcomes.

    Methods We searched Medline, Embase, CINAHL, PsycINFO, ISI Web of Knowledge, ISI Proceedings, ZETOC, BIOSIS, LILACS, and MEDCARIB from their inception to September, 2006, searched reference lists of studies selected for inclusion, and contacted experts. Studies were included if longitudinal and population based. 35 studies from 4804 references were included. Data extraction and quality assessment were done independently and in duplicate.

    Findings There was an increased risk of any psychotic outcome in individuals who had ever used cannabis (pooled adjusted odds ratio=1·41, 95% CI 1·20–1·65). Findings were consistent with a dose-response effect, with greater risk in people who used cannabis most frequently (2·09, 1·54–2·84). Results of analyses restricted to studies of more clinically relevant psychotic disorders were similar. Depression, suicidal thoughts, and anxiety outcomes were examined separately. Findings for these outcomes were less consistent, and fewer attempts were made to address non-causal explanations, than for psychosis. A substantial confounding effect was present for both psychotic and affective outcomes.

    Interpretation The evidence is consistent with the view that cannabis increases risk of psychotic outcomes independently of confounding and transient intoxication effects, although evidence for affective outcomes is less strong. The uncertainty about whether cannabis causes psychosis is unlikely to be resolved by further longitudinal studies such as those reviewed here. However, we conclude that there is now sufficient evidence to warn young people that using cannabis could increase their risk of developing a psychotic illness later in life.
  4. Zentaurus41
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    Come on who believes this bullshit, smoke skunk and your going to go on a killing spree !!
    I find it just typical of the government and the media to try and demonise a mostly harmless plant.
    People with mental problems are going to gravitate towards drugs to self medicate, its not the drugs
    that are the problem as these people are already nuts even before they start smoking.

    But it seems we are all now going back to the days of reefer madness has much really changed ?

  5. Lunar Loops
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    SWIY would be surprised. Many do, well at least the psychosis bit. The story of the man that killed his eighty year old parents and then turned the gun on himself proves that. The Irish Daily Mail (yes same rag effectively) ran the story that he had been in trouble with the gardia for drugs offences the week before and the Mail made the quantum leap to the conclusion that he killed due to an argument about this. Complete conjecture, but it was reported on the radio over here too. No other paper ran the story and there had been nothing heard of it since in the media, but the damage is already done. SWIS has heard MANY people talking about this incident and ALWAYS the conversation is accompanied by the statement that "he was on drugs". Job done, the drugs have killed again, it must be true else why would the papers print it.

    You have to remember we all live in a bubble on this forum where all are of a similar mind, but far from everyone thinks this way. The majority of people that the yak has contact with in rural Ireland have nothing to do with drugs other than alcohol and tobacco, but they are quick to seize on stories such as this to explain what they see as otherwise inexplicable events. Sometimes I see the yak in a state of severe despair (probably the drugs eh) as he has yet again failed to convince folk of their folly. He has long since given up trying with some, as it has been to his detriment in the past.

    Be under no illusion, THIS PROPOGANDA WORKS. It's about to appear on the national news on TV over here and SWIS guarantees that the yak will receive grief from some of those who know some of his activities. Excuse me while SWIS covers his ears to let the yak expel his frustration in sonic form.
  6. Rio Fantastic
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    In the U.K it appears to be literally Reefer Madness all over again. I thought we'd recovered from the crazy propaganda of "cannbis makes you a crazy murdering psychopath", but now it's happening all over again. As soon as we make progress by downgrading Cananbis from Class B to Class C, it looks to be going straight back to Class B with all this propaganda.
  7. Zentaurus41
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    Well do you think the government would ever allow you to take drugs ?

    Even if you had a spacecraft and headed for the stars, if the government knew you where growing pot they would still hound you all over the universe till you where either in prison or dead.

    This is how bad I think things are, the only thing we can do is hit back with publicity campaign, adverts, radio spots and so on. Though the irony is we need people who don't actually smoke to put up a good argument without looking like a complete stoner.

    The other problem is these things cost money, if I ever had it I would put up an advert on billboards across the uk. I would pay for full page adverts in all the newspapers/magazines. i would even go as far as paying for an advert to go on prime time tv to help our cause and I probably wouldnt stop until I was almost broke.

    That's the kind of dedication we need here, we need to try and stop people putting 1 and 1 together and getting 7, the masses need to be educated.
  8. p$2
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    @evilgir .. sorrymani hateto disagree with you but there was a debate going on a couple of years ago as part of the then-popular campaign to have cannbis legalised. remember the mass media is run by the establishment and they are now fronting the backlash, as i will explain...
    @shroomonger i can relate to what you're saying. there is a phraze much used in south london "hold it down". sometimes one needs to do so with ones opinions,to avoid self-incrimination ("how come you know so much about drugs? only the ignorant are trustworthy!") off topic a bit perhaps but... if a fellow jumps out of a window because he's drunk wine and took mushrooms, why doesn't the republik ban the drink!?

    ...and this is entirely delibirate.
    note:this is not just the daily mail. right now it is the entire uk media. a few months before this current hype the so-called-liberal independant(!) newspaper renounced its campaign to have the herb decriminalised on the basis of this so-called new evidence.
    someone who may or may not be me (SWMOMNBY??) spent a lot of time in brixton, south london, which has a big crack and heroin problem. the authorities in london have made the problem worse, in my view, by trying to ruthlessly gentrify the area around Kings Cross in time for the opening of the new international passenger rail terminal at St. Pancras. this has meant that the problem has been shifted to neiboring less-well-off residential areas but more so, 20 minutes tube journey south down the victoria line to brixton.
    a few years ago brixton was in many ways the epicentre of cannabis activism because people were trying to get the "dutch approach" of a clear separation between "sof(er)" and "hard(er)" drugs. the commander of police in the area actually prompted the change in the law with his adoption locally of an "experimental" official policy of not busting people for small quantities of cannabis. those who have been keeping their eyes on current affairs in this part of the world (perhaps thru this forum) will no doubt be aware of al of the above so i shall not elaborate.

    the shocking "new" evidence about the herb's link to mental illness is not in any way new. the creation of a current hype is for strategic political reasons. "respected" corrupt institutions such as the British Medical Associaton and the Royal College of Psyciatrists have their dirty hands all over this.

    what really sickens SWMOMNBM is that this country, word but certainly the locality of brixton and environs has a particular problem with crack. SWMOMNBM has seen bare-faced running and dealing in his own neiborhood... and those involved keep getting younger. there have always been shootings in brixton and it has (nearly) always been "business related" in the broader sense, meaning the people with guns had guns because of their involvement in appropriate criminal activity i.e. "hard drugs". in the opinion of SWMOMNBM the drug cocaine is in itsself likely to cause agression and violence (one could of course say the same of alcohol but i will link this in shortly)...
    in the opinion of SWMOMNBM the drug cocaine is on a level of social acceptability right now virtually on the level with cannabis. if you can smoke a spliff then why not have a line? and if dealing coke is more profitable than skunk then why not? the myth (untrue and now no longer common) which was popular a few years ago that cannabis containing over a certain level of thc is class A feeds into this complex. cocaine is the ideal drug for todays' consumer culture... also the quintessential contemporary british "after work" drinking culture... it makes a night out with work colleages (and competitors) which one more than likely does not actually like, bearable.

    anyway SWI p$!|0c!B€_$!m!|anc€ata does not wish to judgementally hit people with his own preferences of substance, he laughs at the hypocrisy of others who do so; but this is a piece of social commentry and politics because it is not right that the media is reporting the shooting of another youngster (17yo!) in an incident that is 99% likely connected with "business" while the media talks about reefer madness while failing to mention in the same report the prevelance of cocaine (including crack) use, its social acceptability and the mental and broader social problems which it causes.
    all entirely deliberate and conspratorial. imo of course. rant over, to be continued.

    SWMOMNBY is not SWIM! SWMOMNBY may or may not have a friend called SWIM and another called SWIM_II ...
  9. p$2
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    er,newbie can't edit :s posts...
    meant to say here there has always been dealing and related shootings, but the people doing it now are basically teenagers and this makes things more dangerous. an older criminal at least has a bit more sense and experience to think before pulling a gun. but not always.
  10. p$2
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    yes, i should proof-reed my posts beforehitting 'submit'. please accept my apologies in advance. this is a very informative forum and for a long time i though there are so many wise things being said, ps perhaps need not contribute......
  11. Twiglet
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    Who gives a FxxK what the Daily Mail says?
    oh yeah, loads of people, shit!

    ( I Think that's where I got my signature from) :)
  12. p$2
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    again to stress, the daily mail is well known for its crusading right-wing campaingns. this is not one of them. this is a govornment sponsored study which the mail is reporting on along with the entire uk media. the mail obviously loves this kind of thing but i have read similar in many other papers not especailly known for being right-wing....... and on tv as well.
  13. Twiglet
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    theres another thread that mentions this along with opposing the reclassification.
  14. TMM
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    This'd be hilarious if so many people didn't mindlessly go along with it. As it is, it's hilarious in a different, sort of scary way...
  15. Purest
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    This is all just media propoganda, theres a lot of talk about drugs at the moment due to the possible reclassification of several drugs in the UK, because of this they're reporting more and more about negative sides of drugs so that politicians have more "eivdence" to back their claims.
    Why are the government so stupid as to prohibit drugs, if they regulated the drugs instead then it would cut down so much crime and put money in their back pockets.
  16. Nature Boy
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    These statistics completely contradict themselves. Let's see. Smoking cannabis once increases the risk of becoming schizophrenic by 40%. Oh...kay, wherever they got that from, let's just go with it for a second.

    Right then, someone who's used cannabis over 100 times, they're at double the risk. That clearly means, by their statistics, that anyone whose ever smoked cannabis regularly is at an 80% chance of becoming schizophrenic as a result. Riight.

    So 40% of teens/young adults have smoked cannabis and guessing that up to half of those have probably smoked 100 times, this should mean that one-fifth of Britain's young population is at that 80% risk. But one fifth is too high, they have 14% of all headcases down as potheads. I guess they can allow 6% for every other possibility (including acquiring hereditary forms of the illness and other actually proven and not speculated causes) so that they can come up with their number.

    And then some eerie pictures of psychopaths who happened to enjoy a bit of pot, strangely enough none of them being under the direct influence of cannabis at the time of any of the afore-mentioned deaths. But I'm sure those evil cannabinoids swimming around in their systems controlled their minds and caused them to stab and stab again.

    Hmm, 40% of Britain's youth have tried it. Only three cannabis killers? If The Daily Mail's claims are that accurate, shouldn't nearly half of murders in Britain involving young people be cannabis' fault seeing as you don't even need to be high now to be a cannabis-feulled killer by their twisted logic.

    SWIM needs to blaze up after reading this tripe. Then he might go shine his hunting knife.
  17. Joe Duffy
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    SWIM has been smoking skunk, playing Grand Theft Auto and
    listening to Marilyn Manson today, SWIM thinks grandma’s body has
    been taken over by a wolf, inside her skin, and Mr. Wolf has to die!
  18. Heretic.Ape.
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    The actual Lancet meta-analysis that these stories are based on are now available for your own viewing pleasure (I'd love to see some constructive criticism between the study and what comes from reported sordid little mouths ;) ). It can be found here:

    Just a little fodder for further discussion :)

    (Admin: may want to merge with this thread)
  19. Jatelka
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    4804 references were identified by the authors search terms, 175 (3.6%) were judged to be "potentially relevant", 143 of those 175 were excluded.

    Not such a "Meta" analysis after all. An awful lot of research simply wasn't looked at.
  20. Heretic.Ape.
    Re: Smoking One Joint raises mental illness danger by 40% says Daily Mail

    ^ Must have had that second cup of coffee, nice catch ;)
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