NEWS: News.com.au - 27/07/07 'Cannabis increases psychosis risk - study'

[lil angel15]

Cannabis increases psychosis risk - study
By Michael Kahn in London
July 27, 2007 09:54am

USING marijuana increases the risk of one day developing a psychotic illness such as schizophrenia, according to a study that provides some of the strongest evidence yet linking the drug to a mental disorder.

Marijuana is one the most commonly used illegal substances in many countries with up to 20 percent of young people in places like Britain reporting either some use or heavy use, British researchers said, citing government statistics.

Many consider it on par with alcohol or tobacco but the results shows marijuana poses a danger many smokers underestimate, said Stanley Zammit, a psychiatrist at Cardiff University and the University of Bristol, who worked on the study.

The researchers found that marijuana users had a 41 percent increased chance of developing psychosis marked by symptoms of hallucinations or delusions later in life than those who never used the drug. The risk rose with heavier consumption.

"If you compare other substances like alcohol or tobacco it may not be as harmful, but what we are saying is neither is it completely safe," Dr Zammit said in an interview.

Other findings have highlighted the link between marijuana use and the risk of schizophrenia-like symptoms such as paranoia, hearing voices and seeing things that are not there.

But this study marks one of the most comprehensive, thorough and reliable reviews of its kind and should serve as a warning, two Danish researchers wrote in an accompanying comment in the Lancet medical journal, which published the study today.

They said the results mean an estimated 800 cases of schizophrenia in the United Kingdom could be prevented each year by ending marijuana consumption.

"We therefore agree with the authors' conclusion that there is now sufficient evidence to warn young people that cannabis use will increase their risk of psychosis later in life," they wrote.

The team did not look directly at people who used marijuana but instead conducted what is called a meta-analysis by reviewing 35 studies in search of a potential connection between psychotic illness and using marijuana.

They reviewed evidence from studies ranging from one year to 27 years and looked only at research that did not include people already showing signs of psychotic illness.

The researchers also adjusted for factors - like depression or a susceptibility to harder drugs - that could one day lead to a mental disorder to focus more directly on the links between marijuana and psychosis, Dr Zammit said.

"We have described a consistent association between cannabis use and psychotic symptoms, including disabling psychotic disorders," the team wrote.

But both Dr Zammit and the Danish researchers said ultimate proof to show a direct relationship would be have to come through a randomised trial of healthy young people and long-term follow-up.

Such a study, however, was unlikely given marijuana is illegal in most countries and the ethical questions given the drug's known harmful effects, they said.

News.com.au

 

[AnewMan]

"Scientists agree the use of oxygen and pizza will increase their risk of psychosis later in life." they wrote.

 

[lil angel15]

Cannabis smokers risk psychosis
Nigel Hawkes
July 27, 2007

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 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.”

The Australian

 

[lil angel15]

UK scientists reiterate cannabis link to psychosis

Scientists in Britain have produced further evidence linking cannabis use to the possible development of psychosis later in life.

Scientists in Britain have produced further evidence linking cannabis use to the possible development of psychosis later in life.

The research, published in the medical journal The Lancet, indicates that although the risk remains low, users of cannabis are 40 per cent more likely to develop conditions such as schizophrenia.

This review of existing data found what the researchers say is a consistent association between cannabis use and psychotic symptoms, such as hallucinations and delusions.

The researchers report an increased risk of up to 200 per cent for people who use cannabis most frequently.

The authors say the risk to any individual of getting schizophrenia remains low overall, but because cannabis use is so common, they estimate it could be a factor in 14 per cent of psychotic problems among young adults in the United Kingdom.

Bristol University's Professor Glyn Lewis is one of the report's authors, and says the research shows a link, but cannot prove that cannabis causes psychosis.

"It's very plausible that cannabis could have effects on schizophrenia and other illnesses like that," he said.

"There are receptors in the brain which actually respond to cannabis, and those receptors effect the kind of neurotransmitters which in turn have been implicated in illnesses such as schizophrenia."

ABC Online

 

[infectedmushroom]

I've got a strong line of schizophrenia in my bloodline...fuck...luckily i bailed out of smoking weed before it was to late...still, it sucks not being able to toke. Some people just don't realize how lucky they truly are.

 

[kapow]

But none of the studies they looked at covered long term use, did they? Except for one 27 year study?

I've hardly seen any unbiased or flawed studies into marijuana so reviewing them all isn't going to be much use IMO.

"We therefore agree with the authors' conclusion that there is now sufficient evidence to warn young people that cannabis use will increase their risk of psychosis later in life," they wrote.

But both Dr Zammit and the Danish researchers said ultimate proof to show a direct relationship would be have to come through a randomised trial of healthy young people and long-term follow-up.

I think that says it all. Why did they waste there time on this?

 

[juice_soldier]

fuck weed... its shit.,. why would u wanna do it.. lol...

 

[kapow]

^^ f*ck <insert name of drug you don't like here>... its shit.,. why would u wanna do it.. lol...

No one wants to read that kind crap. say something constructive/relevant or not at all.

Anyway.. even according to there research it's 14% of an already small subset of people. What makes up the rest? I want to know if researchers have conducted studies on more common chemicals in the foods we eat every day and other pharmaceuticals that are prescribed all the time. I'm sure we could find even greater links to all sorts of things that we consume every day if the same amount of time was invested into the research as is to weed.

A guy I know who has been prescribed valium since he was about 18 (he's now in his late 30's) is quite positively going schizophrenic and thinks members of his family in another state are conducting mind control experiments and influencing factors of his life remotely... No joke. It's bizzare stuff really, and he's never touched weed in his life. And it's not some temporary type of psychosis like most of the 14% of these people are getting, he's been like this for a long time and he doesn't realize how f*cked up he is.

"There are receptors in the brain which actually respond to cannabis, and those receptors effect the kind of neurotransmitters which in turn have been implicated in illnesses such as schizophrenia."

schizophrenia is not just associated with cannabinoid receptors, is it?

 

[juice_soldier]

^ My comments stem only from my best friend and parents... and of course personal experience...

 

[lil angel15]

Cannabis doubles chance of psychosis
Bellinda Kontominas Medical Reporter
July 28, 2007

PEOPLE who smoke cannabis regularly more than double their risk of developing psychotic illness later in life, according to research that calls for increased awareness of the dangers of the drug.

Researchers found that among all cannabis users, including social and habitual users, the lifetime risk of psychotic illness increased by 41 per cent.

More than one third of Australians over 14 years of age have smoked cannabis, or marijuana, at least once in their life and one in 20 have used the drug in the past week, according to figures on drug use from the Australian Institute of Health and Welfare. Of the 1.8 million Australians who have recently used cannabis, one in six use it every day and a further one in five use it every week.

The study found the increased risk for psychotic illness was relative to the dose. Those who smoked cannabis regularly were at an increased risk of between 50 per cent and 200 per cent of developing schizophrenia and disorders with symptoms including hallucinations or delusions.

This also suggested that stopping cannabis use would decrease the risk, said the lead author, Dr Stanley Zammit, a psychiatrist from Cardiff University and Bristol University in Britain.

Previous studies have had trouble unravelling the link between cannabis use and psychotic disorder. Smoking the drug could be a symptom of psychotic illness, rather than a cause, the research found. The researchers re-examined data from 35 international studies on psychotic illness and cannabis use involving more than 100,000 participants. Factors such as pre-existing mental illness, the use of other illicit drugs, IQ and social class were filtered out of the sample to try to isolate the effect of cannabis.

Dr Zammit said there was now sufficient evidence to warn young people that using cannabis could increase their risk of developing psychotic illness later in life, despite a lack of evidence to confirm a cause-and-effect relationship.

The risk was relatively low but significant, he said.

One in 100 people had a chance of developing severe psychotic illness. That risk increased to 1.4 in 100 if they had ever smoked cannabis.

In an accompanying comment, Merete Nordentoft and Carsten Hjorthoej, of the department of Psychiatry at the Copenhagen University Hospital, said cannabis had long been considered a harmless drug and its potential long-term effects on psychosis had been overlooked. "There is a need to warn the public of these dangers, as well as establish treatment to help young, frequent cannabis users," they wrote.

Cannabis accounted for 45 per cent of hospital admissions due to drug-induced psychosis in 2003-04, according to a study published in the Australian Medical Journal. John Saunders, Professor of Alcohol and Drug studies at the University of Queensland, said the latest research strengthened the need for increased education on the dangers of cannabis.

Brisbane Times

 

[swilow]

Um, what does this mean?

"If you compare other substances like alcohol or tobacco it may not be as harmful, but what we are saying is neither is it completely safe," Dr Zammit said in an interview.

If I'm reading it right, thats the first time I've heard it said that Tobacco and alchhol are more harmful then weed. Finally, some recognition.

 

[lil angel15]

Dope far worse than fags
July 31, 2007 12:00am

SMOKING a single marijuana joint has the same impact on breathing capacity as up to five cigarettes, says a New Zealand study published today in Thorax, a specialist British journal.

It follows a study published in the British journal The Lancet on Saturday that said there was now clear evidence of a link between cannabis smoking and mental ill-health.

In the study now reported in Thorax, Medical Research Institute of New Zealand doctors recruited 339 volunteers, who were divided into four categories - those who smoked only cannabis, those who smoked only tobacco, those who smoked both, and those who smoked neither.

Cannabis-only smokers were defined as those who had smoked the equivalent of at least one joint a day for five years; tobacco-only smokers were those who had smoked the equivalent of a packet of cigarettes a day for at least a year.

All were scanned by computed tomography (CT) to get a high-definition image of their lungs and were given tests to assess their airflow, the term for their respiratory efficiency.

The most serious damage was found in tobacco smokers - both tobacco-only and combined users - who were the only volunteers to have emphysema, a degenerative and crippling lung disease.

Cannabis smokers had lighter symptoms, such as wheeze, cough, chest tightness and phlegm, which tobacco smokers also had.

But the CT scan also revealed that, among cannabis smokers, fine damage had occurred to their lungs. This had happened in small fine airways that are important for bringing in oxygen and taking away waste gases. As a result, their lungs had to work harder.

The extent of the damage rose in proportion to the number of joints that had been smoked.

In statistical terms, each joint that was smoked was the equivalent of smoking between two and a half and five cigarettes in one go for impairing lung efficiency.

The researchers, led by Richard Beasley, said the discovery of this hazard is "of major public health significance" given that cannabis is the most widely-used illegal drug worldwide.

According to the 2006 report by the UN Office on Drugs and Crime, an estimated 160 million people use cannabis, also called marijuana.

Beasley suggests that the reason for cannabis' heavy toll on the lungs stems is that joints are usually smoked without a filter and are smoked down as far as possible, which means the smoke is hotter when it arrives in the lungs.

In addition, cannabis users tend to inhale smoke more deeply and then hold their breath to get a bigger "high".

Daily Telegraph

 

[Splatt]

What about bongs??

 

[Prince Planet]

Just to give this questionable Meta study a bit of context:

Taken from The Guardian

http://www.guardian.co.uk/science/2007/jul/28/drugs.drugsandalcohol

Bad science

Cannabis data comes to the crunch
• Ben Goldacre
• The Guardian
• Saturday July 28 2007
You know when cannabis hits the news you're in for a bit of fun, and this week's story about cannabis causing psychosis was no exception. The paper was a systematic review and then a "meta-analysis" of the data which has already been collected, looking at whether people who smoke cannabis are subsequently more likely to have symptoms of "psychosis" or diagnoses of schizophrenia. Meta-analysis is, simply, where you gather together all of the numbers from all the studies you can find into one big spreadsheet, and do one big calculation on all of them at once, to get the most statistically powerful result possible.
Now I don't like to carp, but it's interesting that the Daily Mail got even these basics wrong, under their headline "Smoking just one cannabis joint raises danger of mental illness by 40%". Firstly "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%."
In fact they identified 175 studies which might have been relevant, but on reading them, it turned out that there were just 11 relevant papers, describing seven actual datasets. The Mail made this figure up to "35 studies" by including 24 separate papers which the authors also found on cannabis and depression, although the Mail didn't mention depression at all.
They also said that "previous studies have shown a clear link between cannabis use in the teenage years and mental illness in later life". They then described some of these previous studies. These were the very studies that are summarised in the new Lancet paper.
But what was left out is as interesting as what was added in. The authors were clear - as they always are - that there were problems with a black-and-white interpretation of their data, and that cause and effect could not be stated simply. For ongoing daily users, as an example, it's difficult to be clear that cannabis is causing people to have a mental illness, because their symptoms may simply be due to being high on cannabis all the time. Perhaps they'd be fine if they were clean.
It was also interesting to see how the risk was numerically reported. The most dramatic figure is always the "relative risk increase", or rather: "cannabis doubles the risk of psychosis", "cannabis increases the risk by 40%". Because schizophrenia is comparatively rare, translated this into real numbers this works out - if the figures in the paper are correct, and causality is accepted - that about 800 yearly cases of schizophrenia are attributable to cannabis. This is not belittling the risk, merely expressing it clearly.
But what's really important, of course, is what you do with this data. Firstly, you can mispresent it, and scare people. Obviously it feels great to be so self-righteous, but people will stop taking you seriously. After all, you're talking to a population of young people who have worked out that you routinely exaggerate the dangers of drugs, not least of all with the ridiculous "modern cannabis is 25 times stronger" fabrication so beloved by the media and politicians.
And craziest of all is the fantasy that reclassifying cannabis will stop six million people smoking it, and so eradicate those 800 extra cases of psychosis. If anything, for all drugs, increased prohibition may create market conditions where more concentrated and dangerous forms are more commercially viable. We're talking about communities, and markets, with people in them, after all: not molecules and neuroreceptors.

Also:

Taken from the same Lancet report one of the authors says,

"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."

The same applies here in Australia, there has not been a significant increase in schizophrenia rates even though cannabis use has increased from the 1960s through to the late 1990s. If there was a causal link one would assume there would be an increase in schizophrenia rates to correlate with the increase in smoking rates. Once again common sense prevails.