For the past few  weeks UKCIA and CLEAR have been promoting a study being carried out by Manchester metropolitan University (MMU): A study into cannabis and mental illness. See the introduction to the study here

It was just about 10 years ago now the campaign of “Reefer Madness V2” hit the news, during which it was claimed cannabis caused severe mental illness – Psychosis and schizophrenia. That was a very serious claim to make and a very disturbing one; mental illness is one of the last taboos and it scares people, which is why the prohibition lobby were so keen to promote the scare stories. Much of the claims were eventually shown to be overstated but were used by to attack the then recent downgrading of cannabis to class C under the misuse of drugs act. This wasn’t the first time this had happened of course, with Reefer Madness being an important part of the original campaign against cannabis (if you haven’t seen the film, do watch it),  hence the term “Reefer Madness V2”.

Reefer Madness V2 was a destructive and damaging campaign for many reasons, not least because it played on fears of mental illness but also because it was touted by the prohibition lobby it was seen for what it was by many cannabis users, who understandably perhaps treated all discussion of the issue as prohibition rubbish.

Now some time has passed and most of the alarmist claims about cannabis as a cause of mental illness have been shown to indeed be hype, we have come to accept a link between cannabis use and mental illness in some people. The nature of this link is far from clear and isn’t anything like the simple causal link the prohibition lobby were claiming, but it does seem that the people at risk of mental illness do react badly to cannabis and yet for some reason often tend to use it heavily, which makes the situation worse.

As we know cannabis isn’t s simple “drug” in the sense that it is the raw product of a herb and as such “cannabis the drug” is actually the combined effect of several active chemicals produced by the plant, most importantly (but by no means only) THC and CBD.  It may well be that plants low in CBD pose a higher risk to this section of society at risk of developing mental illness.

It also seems logical to assume that cannabis use by children isn’t a good thing as the brain is still developing. Brains grow as they learn, a process called “plasticity” and drugs (and also some things that aren’t drugs) may well interfere with this growing/learning process. So keeping kids away form drugs of all kinds, not just cannabis, is a pretty obvious thing to do.

So rather than “reefer madness V2”, the mental health campaign of the last decade should have taught us was that proper controls are needed over the cannabis supply industry. Far from being an issue that supported the prohibition argument, this is one for law reformers, indeed it’s one of the most powerful arguments in favour of cannabis legalisation.

It does seem that a very small number of people might be at risk from using cannabis, if not of actually of developing an illness they wouldn’t otherwise have had, then of becoming more seriously ill and for longer. At this time, there’s no way of knowing who might be in this high risk category. That’s the thing about serious mental illness; there is no way to spot it in advance, there never has been.

The researchers at MMU put it this way:

However, a relatively small proportion of users, with a so-called ‘high schizotypy’ personality profile (characterised by a willingness to adopt irrational beliefs, susceptibility to perceptual disturbances and poor interpersonal social skills) are at increased risk of experiencing proportionately fewer positive and more negative effects of the drug. We believe that such individuals may, through continued use of cannabis, be putting themselves at increased risk of later mental illness.

Is it possible then to spot the people at risk of developing psychosis through their cannabis use before it happens, before they actually get ill? Are there any tell-tale signs they show when using cannabis which are actually warning signs that would set them apart from most other users? If some kind of “symptom” could be identified then it would be possible to target advice about cannabis to these people to help them make a well-informed decision about their cannabis use. That is the aim of this study.

Essentially, we want to see if people with ongoing problems, who have also used (and may continue to use) cannabis, have the same or similar reactions to the drug as people without a history of mental health problems, and if not, how their responses differ.

A very important outcome of our proposed research is the identification of cannabis-induced experiences that could predict increased proneness to subsequent psychosis in currently ‘healthy’ individuals, and your involvement in our study could help us achieve this goal!

Scientists have a strange language for describing this sort of thing, they call it a “pre morbid” indication. “Morbid” in this sense means

Relating to or caused by disease; pathological or diseased

So “pre morbid” means something related to or caused by the disease that happens before the illness shows. Although there are no clear-cut signs of an emerging mental illness, there are “pre morbid indications” that really only become evident with the benefit of hindsight, they’re usually the sort of mood swings most teenagers go through to some extent or other.

The reason this study caught my eye though was through hearing the stories which made the news a few years ago which were presented as “evidence” that cannabis caused psychosis. A common theme ran through most if not all of the stories; all the young people described had been very heavy cannabis users.

Now most people who discover cannabis enjoy the occasional “session” where everyone gets very stoned, but this was something different. Many of the stories told featured kids who had taken to cannabis like a duck to water, toking away every day and getting through vast amounts. Now a simple conclusion to draw from that is that heavy use caused the illness, but it is also more than possible that the illness caused the heavy use. Is it possible that this heavy use was one of these pre morbid indications? In which case, did these kids experience something more or different to the average “normal” user? This is the sort of thing, with luck, this study might answer.

So if you have a history of mental health issues – of any kind – and you have used or do use cannabis (including if you do so because you find it helps your condition), please take part in this study, you can see how to do so here

Serious mental illness strikes out of the blue and in all the years scientists have been looking at it no advance warning has ever been identified. Psychosis is a nasty illness, it always has been a nasty illness, it has always existed at about the same level as it does today and it has always affected the same section of society; mostly male, mostly in late teenage/early 20’s – young people whose lives are often wrecked by this devastating illness

A few years ago in 2008 a large study in Denmark (familial predisposition for psychiatric disorder – read it here) made this observation:

Psychotic symptoms after cannabis use should be taken extremely seriously. It is recommended that individuals with a cannabis-induced psychosis  …  be treated as though the condition is a first sign of schizophrenia, regardless of predisposition to a psychiatric disorder.

So possibly a cannabis induced psychosis might be an early warning of an impending illness, but ideally it would be far better to find an indication way before that happened. So looking far beyond the scope of this study, is there an interesting possibility that could flow from this line of thinking? If it could be demonstrated that people at high risk of developing a psychotic illness really did react in an identifiably “different” way to cannabis, could this in some way provide an advance warning of a developing illness? Having advance warning of an illness like schizophrenia would be dynamite and a potentially wonderful thing. It would be beyond irony, given the prohibitionist hype, if cannabis were to provide that long looked for advanced warning.