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Cannabis and mental health

Certain studies suggest that cannabis can worsen some mental health disorders, or have linked episodes of schizophrenia with the onset of heavy cannabis use. The Department of Health stated in January 2005 that cannabis was 'an important causal factor' for schizophrenia. But it's also been found that one active ingredient of cannabis could be used in treating psychosis. What's clear is that there is still a lot of research to be done.

DrugScope says, 'It is reasonable to say that those with a history of mental illness may be vulnerable to cannabis-induced psychosis. However, there is no convincing evidence of cannabis use causing psychosis in people who do not already have mental health problems.' In other words, it is unlikely that cannabis could cause schizophrenia or other mental illness in someone not already predisposed to it.

Also, it's suggested that people with mental disorders often self-medicate using cannabis, rather than cannabis use causing the disorder itself.

Rethink, the mental health charity, agree that cannabis alone is unlikely to cause serious mental health problems. But they feel strongly that it is a causal factor, especially where young people are concerned, and have collected evidence to show this. They're worried that cannabis is presented as a harm-free drug, and have called for further government research and education work so that young people are more aware of the mental-health risks. A Rethink statement released in January 2006 also stated: 'It is particularly important that people aware of vulnerability to psychotic illnesses in their family are informed of the potential dangers of cannabis use.'

The following statement has been written for Channel 4 by Rethink www.rethink.org.

Rethink statement

Cannabis – everyone's got a different name for it, and everyone's got a different view about it.

Some think it's a cure-all substance, others want to cut people's hands off for using it. And that's why it's been really difficult to get people to look at the real facts about cannabis.

But there's no doubt that smoking a lot, especially if you're in your teens, can cause you a lot of problems. That's not to say that everyone who smokes a lot will develop a mental illness.

It's a bit like peanuts: for most people, they're a bar snack; but for some people, they're a disaster.

That's why Rethink has been campaigning to make sure that young people get the real facts about cannabis.

We want people to know that:

• If you smoke when you're under 18, you're doubling or tripling your chances of getting psychotic symptoms.
• If you smoke heavily for a long-time, you're also increasing your chances of psychosis.
• If you've already got a mental illness, using cannabis is going to make things much worse in the long run.

Cannabis causes some people more problems than others.

You might know people who have smoked all through their lives and seem fine, but that doesn't mean that you will be. Why this is, we don't know yet – it might be genetic, but it might be because of other factors. But those who are affected badly by cannabis are affected really badly.

Getting psychosis is no joke, though often we talk about people being 'nuts' and 'loony' as though it is funny. A lot of people recover from psychotic illnesses like schizophrenia, but even then they often have trouble with things like getting a job and hassle from their neighbours.

We don't want more people locked up for using cannabis, though. We don't want cannabis to go back to Class B. Changing the law in such a small way won't make any difference to how many people use cannabis. How many people do you know who would have a different attitude to cannabis if it were Class B again?

We do want the Government to put money into health education – not preachy, patronising campaigns from the Government, but real information for people, better education for schoolchildren and more help and support for people with mental illnesses who want help with their cannabis use. Real health education that's not patronising has worked to cut smoking. We need to do the same kind of thing for cannabis.

And we want more help for people trying to cut down or stop using cannabis. At the moment, drugs services give help to people with problems using Class A drugs, but it's harder to get help if you've got a problem with cannabis. That needs to change.

So are there any advantages of cannabis? Well, we don't have a problem with medical research on cannabis – in fact, we want it to continue. But what a lot of people don't realise is that cannabis-based medicines are actually quite different from the cannabis you buy on the street.

You see, cannabis is a pretty complicated plant – it contains about 60 different active substances. One of these, called THC, gives you a 'trippy' effect. Another one, CBD, seems to work as a pain reliever. The stuff you buy in the street has a lot of THC in it – it's grown that way, so it gets you more stoned. But medicines include much more CBD. So there is a big difference between taking cannabis as a medicine and smoking stuff from your local dealer.

It's these kind of facts that Rethink and other mental health charities want to get into the open. We want young people to make informed decisions about using cannabis, based on facts and evidence, not on myths. We trust young people to do that, but we need the Government to help us give people the facts.

If you want more information about cannabis and mental illness, go to: www.rethink.org.