July 20, 2006

UK advocacy group urges Govt. to Educate Public about Mental Health risks of Cannabis / Marijuana

Rethink - the UK mental health advocacy group (equivalent to NAMI in the US) today strongly urged the UK Government to act on its promises of launching a long-term public health campaign to raise awareness of the link between cannabis and schizophrenia / mental illness. The call from Rethink comes six months, to the day after the Home Office decided against reclassification and pledged to launch a “massive campaign” to raise awareness of the link between cannabis and mental illness. As we've noted before, schizophrenia researchers have said they believe that between 8 and 13 percent of schizophrenia cases are likely to have been triggered by marijuana / cannabis use., which equates to approximately 200,000 to 350,000 people in the USA.

Recently, British Psychiatrist Professor Robin Murray blasted the government for not giving sufficient warning to the public over the mental health risks associated with Cannabis. Professor Murray who treats people with Schizophrenia has observed over the years that many of his patients recovering from Schizophrenia were regular users of cannabis. According to Professor Murray, a single active ingredient found in Cannabis, tetrahydrocannabinol is mainly responsible for long-term psychological effects on many of his patients.

At the annual Royal College of Psychiatrists’ meeting in Glasgow, Murray told fellow psychiatrists that the government should honour its earlier promise made by former Home Secretary Charles Clarke to publicise the links between mental health problems and the use of cannabis. Describing his on view towards Cannabis use as agnostic, Murray stated that "What I think is much more important is that the public should know that cannabis is actually a drug."

Paul Corry, Rethink Director of Public Affairs said:” Rethink is concerned by the lack of progress concerning this critical public health issue. We know that early-age users, long-term users and people with a family history of mental illness are at a high risk of developing psychosis from smoking cannabis – the problem is that they don’t know it because the government has failed to act on its promise.”

As a result Rethink has launched a cannabis survey to find out people’s knowledge and attitude towards cannabis. Currently, there is no consistent evidence on the public’s knowledge of the mental health risks of cannabis. Rethink hopes that this survey will provide a baseline to help future awareness projects.

Mr Corry added: “In France, millions of euros are being spent on taking mental health warnings to young people. If the Government wants to be taken seriously campaign it will need to invest accordingly. This is a huge public health issue with potentially serious consequences for many thousands of the four million regular cannabis users in this country.”

Rethink has been at the forefront of campaigning about cannabis and its links to psychosis and was the first mental health charity to start a campaign to highlight these risks to the general public. For years, Rethink has been calling for: -

• a long-term public health campaign to raise awareness of the link between cannabis and mental illness

• more research to fully understand the effects of cannabis use on mental health

• drugs education in schools on cannabis and mental health

What is the link between cannabis use and mental illness?

Worsening symptoms
There is a general consensus that long-term cannabis use, and sometimes short-term cannabis use, worsens psychotic symptoms (paranoia, hallucinations and delusions) among people with schizophrenia. This is also true for people with bipolar affective disorder (manic depression) experiencing psychotic symptoms.

‘Trigger’ effect
There is strong evidence from a wide range of sources that long term and short-term use of cannabis can “trigger” a psychotic episode of psychosis in people who are at high risk of developing psychosis – for instance, people who have close family members who have schizophrenia.

Causal link
There is a growing body of evidence that suggests cannabis may be a causal factor in the development of psychosis. This does not mean that cannabis is a necessary or sufficient cause of psychosis - it is clear that many people use cannabis and do not develop psychotic symptoms; conversely, many people who have psychotic symptoms have never used cannabis.

However, cannabis may be a causal factor. For example, flamingos only become pink if they eat shrimps; other animals, though, do not become pink when they eat shrimps. Shrimps play a causal role in pinkness, but they alone cannot cause pinkness.

There is emerging epidemiological evidence that long-term use of cannabis, particularly if commencing in teenage years, can lead to increasing numbers of people developing the illness. A study by Jim Van Os (2004) of 2,500 adolescents found that among those who had no vulnerability to psychosis, cannabis had a marginal effect, increasing the chances of psychotic symptoms by 6.3%. However, among those who had a predisposition to psychotic symptoms, cannabis use increased almost doubled their chance of developing these symptoms (the risk went from 26.2% to 50%).

A different study (Fergusson et al, 2004) suggested that people who used cannabis daily increased their chances of psychotic symptoms by 1.6-1.8 times. A sophisticated technique called structural equation modelling was used to investigate the possibility that cannabis use was increased by psychotic symptoms, rather than the other way round. The findings of this study suggest that this is not the case and that the level of psychotic symptoms is to be explained by cannabis use.

This population research has been underwritten by research on the effects of cannabis on brain chemistry and functioning.

Some preliminary work has been done on the possibility of using one active ingredient of cannabis in the treatment of psychosis. In one study, people with schizophrenia who received a dose of cannabidiol experienced fewer side effects, less weight gain and prolaction compared with a similar group of people using amisulpride. Both groups experienced a similar decrease in psychotic symptoms. This is promising, but there needs to be a great deal more research before we can make any claims about the therapeutic benefit of cannabidiol. In any case, cannabidiol is only one of the sixty active ingredients in cannabis. Even if cannabidiol does prove to have a therapeutic effect on psychotic symptoms, this does not change the evidence on cannabis itself.

What is the Government saying and doing about this?
The Government seems to be taking the possibility of cannabis playing a causal role more seriously. A spokesman from the Department of Health acknowledged in January 2005 that:

"There is medical clinical evidence now that there is an important causal factor between cannabis use and schizophrenia - not the only factor, but an important causal factor. That is the common consensus among the medical fraternity."

In March 2005, the Home Secretary asked the Advisory Council on the Misuse of Drugs to consider the evidence on cannabis and mental illness and the question of classification of cannabis. Rethink staff and a service user gave evidence to the Council in September 2005 and they are expected to issue a report by the end of the year.

The Home Office and Department of Health are developing information materials about cannabis for people who have mental illness. However this project only has a budget of £230,000 so it is unlikely that materials will reach everyone who needs this information.

What more should be done about this?
Rethink believes that many young people view cannabis as a risk-free drug; often it is viewed as less harmful than tobacco. Reclassification to class C has created a confusing picture about the risks of cannabis. However, Rethink does not believe that a further reclassification to class B would resolve this issue – that will create more confusion and further undermine the Government’s credibility on the issue. What is needed is better public education, better information for people with mental illness and more research.

A long-term, well-funded public information campaign aimed at publicising the mental health risks associated with cannabis is essential to counter the “risk-free” message. It is particularly important that people aware of vulnerability to psychotic illnesses in their family are informed of the potential dangers of cannabis use.

It is also essential that people who have already developed mental illness become aware of the potential dangers of cannabis use. The project to deliver information to people with severe mental illness needs better, more long-term funding.

More research is essential to clarify the effect of cannabis on mental health and pre-existing mental illness.

More Information: Schizophrenia and Cannabis Summary


If i had not smoked marijuana i would not have fallen ill. I was normal up to the point i tried that funny little cigarette.I never felt paranoia until

Posted by: nightflyer at July 23, 2006 01:04 PM

I believe cannabis plays a big part in the "trigger effect" forementioned. But i do think that you are worming your way around the subject and looking for a simple answer to a complex problem. I have friends who believe they are scizophrenic. They also believe that alcohol is the biggest problem that brings it on. Professer Murrey wants us to know that cannabis is actually a drug. Maybe he should realise that we know it is a drug and some people smoke it not to be a rebel but because they are much safer smoking it than drinking alcohol. May i remind you that there has never been a single recorded death due to cannabis. As for the article about the suicides due to the illness maybe they were depressed because they felt different and giving their problem a name wont make them feel more in control. I think its time you treat this like the problem it is. I want fact no rumours.

Posted by: blacksheep at July 24, 2006 04:14 AM

Actaully, from what I've read on the subject there is just as must evidence to suggest that there is no link as there is to suggest there is a link. I have no bias one way or another. But I think that Dr.'s that do believe a certain person developed the illness from pot wouldn't say so for 2 reasons. 1.) there is no real evidence. 2.) that is a serious burden that develop this illness and have to live the rest of your life knowing you did it to yourself.

I have no problem believing the trigger effect, that would explain my case ( of course I stopped smoking pot when my first break occured over 8 years ago ). I really don't feel any better about my illness thinking that I brought it on myself. But I know the potential was always there, simply by observing my teenage years, I am schizoaffective and am quite sure I have mood disorder as a teen. I was also using heavily when I first broke. But I also know life stress conditions may have contributed equally to my illness and I know that many many studies have found NO link between pot and schizophrenia.

Also, it should be considered that people that develope schizophreia ( just like people that develope mood disorder ) have a 50% rate of drug abuse, so certainly if half of the people who develope the illness use drugs there would appear to be a link. The actual goings on ni the brain are still not agreed as fact by the overall mental health community.

Still, everyone shold just say no, it's just not worth it. I often think i would prefer to lose a limb or be stuck in a wheel chair that live with this hell.

Posted by: Richard at July 24, 2006 04:55 AM

growing up as an only child i felt differnet much of the time. i had a lotta
playmates and stuff. did acting in movies and tv from 8-14. but so much
especially at night, i felt odd, different, internally. i watched tv a lot
and read thousands of books. i did allright in school, b average. at 16, i
began to almost crack. we took a trip to europe for 7 months then, for
my parents sabbatical, a working vacation, we would have to make an investigate
report on europe as part of the sabbatical arrangement. i started getting
surrealistic, derealization. it is slighty possible, that these chemical
agents are in the atmosphere, because of ongoing warfare between the soviet
countries and the capitalist countries, hallucinogens etc. then why wasn't
everyone else affected? i was mildly alcoholic already by age 16. upon
returning to u.s.a. summer 1967, the whole nation was on lsd, so i did it
too about 100 times. all those guys, became lawyers, doctors, construction
contractors and stuff. by the time of the moon landing in 1969, i had
totally cracked. partly because of a high school marriage, a baby given
away to her cousin, and her radical infidelity and my loyalty, and the hassles
of growing up in los angeles, ca a very fast-paced scary environment.
it wasn't like growing up in a fishing village in nova scotia, i'll tell
you that. eclectic psychiatrists help. i don't like mental health being
summed as just the brain and all that. life events affect the brain too.
life is dangerous to your health. lol. its too nazi, materialism, all
we are is protoplasm, really crass. people are not just protoplasm.
actually, the whole etiology of schizophrenia is unknown. it may be caused
by lasers from another galaxy as far as medical science knows. lolol.

Posted by: jeanlafittepirate at July 24, 2006 09:44 PM

i don't feel pot causes schizophrenia. however, after studying what pot does in the brain, i can see very clearly that it would make symptoms of schizophrenia worse. In some cases, much worse.

People are often experimenting with pot about the same time they become ill, but I don't think it is the root cause of schizophrenia. The brain changes that are found in schizophrenia started long before the person was even born.

Pot is not 'the safe alternative to drinking'. It is just as much a drug as alcohol is. People who like it may have some very elaborate reasons why it's safe or great or not harmful, but after carefully studying the chemistry of it, I am convinced that it is a VERY bad idea for people with schizophrenia or about to become schizophrenic, to smoke it.

Posted by: slc2 at July 27, 2006 10:08 AM

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