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“Think cannabis is harmless?” No. Does anyone? But what about propagating drug hysteria? Is that harmless?


24th October 2013

A week ago, the Daily Mail published a story entitled "Think cannabis is harmless? It drove this grammar school boy insane – then killed him". This is not the first time that the Mail and other newspapers have used personal tragedies to generate panic about cannabis, particularly related to psychosis, and particularly aimed at concerned parents. In the past, the ISCD and other voices who challenge drug misinformation have hesitated from getting involved, as it seems rather distasteful to engage in a debate about evidence over the body of a young man. However, this has allowed the Mail and others to go unchallenged in their willingness to exploit their readers, grieving families and the deceased themselves. They sell wild speculation and morbid sensationalism dressed up as a heroic crusade against enemies in our midst. The headline alone takes aim at two insidious foes for readers to fear and hate; the army of straw men who think that cannabis is harmless, and the drug itself, which becomes personified as a killer.

You do not need telling that newspapers are not scientific journals, nor that many journalists are talented in creating eye-popping nonsense. That's not news. What we want to point out is that these stories are not just a diversion from the real issues; they may themselves be harmful. Whilst posing righteously as exposing the threat of cannabis-induced psychosis, the Mail may in fact be contributing to the problem, through their effects on public understanding and political tides. To explain how, we need to explore the evidence of links between cannabis and psychosis.

Cannabis is associated with psychosis (a symptom) and schizophrenia (an illness where this symptom is persistent) in complex, contradictory and mysterious ways. The evidence does demonstrate various links that we all should all be aware of, especially cannabis users and parents. However, the evidence doesnot support anything like the level of fear propagated in the media.

Whilst someone is actually 'stoned', the principal psychoactive component of cannabis, THC, can sometimes have unwanted psychosis-like effects, such as anxiety and paranoid delusions. This is a reason that many people try the drug and don't like it; but transient paranoia isn't the same as schizophrenia. Persistent drug use of any kind may seriously complicate and worsen pre-existing mental health problems, and the use of cannabis seems able to exacerbate symptoms in a person with an illness like schizophrenia, or latent vulnerabilities.

On the other hand, the second key component in cannabis, cannabidiol (CBD), has powerful antipsychotic and anti-anxiety properties, so people with schizophrenia, or teens predisposed to psychotic symptoms may feel relief from consuming cannabis. Paradoxically, this self-medication is very likely to be counterproductive in the long-run because of the THC content, and so vulnerable young cannabis users should be given this explanation, and positive support to minimise or stop their use. The paradox of short-term relief versus long-term exacerbation shows the need for great sensitivity to the experiences of young cannabis users with mental health problems; they may not be being delusional and selfish by using the drug as the Mail implies, but simply doing what, in their experience, helps.

Several studies have suggested that regular, long-term cannabis use is one of a number of environmental factors that, in combination with certain genetic predisposing factors, may significantly increase a young individual's chance of experiencing psychosis and developing schizophrenia. However, numbers of people being diagnosed with schizophrenia remained stable over time during which the number of cannabis users increased and average strength rose significantly. There are clearly nuances that remain to be understood, but despite this uncertainty, we can entirely rule out the possibility that cannabis causes a level of risk of schizophrenia that would warrant the media coverage of the issue.

Cannabis use is fairly common (around 1 in 3 have tried it), and use typically begins in teenage years and young adulthood. Schizophrenia is fairly rare, (about 1 in 200 will be diagnosed at some point in their lives) and also typically begins in teenage years and young adulthood. It should be noted that when a condition is rare, less concern is warranted by an increase in risk, compared to if a condition is common. For example, a doubling in the risk of cancer or heart disease, very common conditions, should really worry us. A doubling of the risk of being struck by lightning shouldn't really scare us at all.

A doubling in the risk of psychosis, Robin Murray's rough estimate for the maximum increased risk of heavy cannabis smoking, lies somewhere in between; far from meaningless, but certainly not a major public health catastrophe. Based on a similar estimate of risk, it has been calculated that very roughly, the chance of a 20 to 24 year old man (the group at the very highest risk) developing schizophrenia this year will be raised from about 1 in 3,100 to 1 in 1,900 if he is a heavy cannabis smoker. This is not, in our view, even the most serious risk of cannabis. Roughly one in ten cannabis users are addicted; they have lost some degree of control over their use. Heavy cannabis use before adulthood can interfere with education and intellectual development, impacting on learning and employment opportunities.

The other major negative impact of cannabis use is that of getting a criminal conviction for possession or other minor cannabis offences. These have a profound impact on future employment and travel opportunities, disproportionately affect the UK minority ethnic population, particularly black young men, and may preclude them from serving as police officers, teachers, nurses and politicians. Those, in our view, are far far more significant problems, but perhaps they are less suited to creating sensation than the fear of one's children becoming "insane.

In comparison with this uncertain 2-fold increase in psychosis risk from heavy persistent cannabis use, the risk of lung cancer from heavy and persistent cigarette smoking is increased by about 25 times. Now that is a public health catastrophe. Cannabis smoke can irritate lungs, but is not definitively linked to lung cancer. Cigarettes are moreover a particular catastrophe for people with schizophrenia, who smoke at vastly higher rates than the general population, a major reason they live shorter lives on average. But the association between legal tobacco and psychotic illnesses, or indeed suicide, is not of much interest to the media.

If cannabis use does increase the risk of schizophrenia, this means that cannabis use is causing some 'extra' cases that wouldn't occur if cannabis didn't exist. However, unless cannabis turned out to be causing a much higher risk increase than the most alarming scientific estimates, it remains true that the majority of the young people who smoked cannabis and developed schizophrenia would have developed the illness in any case. By analogy, consuming even low amounts of alcohol is causally linked to an increased risk of breast cancer, but most women who develop the cancer and also drink alcohol would have developed the cancer anyway. The implication of this key fact is that when any particular case of schizophrenia is definitively blamed on the cannabis use of that individual, such as in the Mail's article, this is always misleading speculation (and thus, on the face of it, always in breach of the codes of press standards to which the Mail is committed).

A cannabis-using young person experiencing psychotic symptoms, or diagnosed with schizophrenia, should be told that cannabis is likely to worsen their condition, may have been a factor in causing it, and be strongly encouraged and supported to give up the drug. To instead dishonestly affirm that their choice to use cannabis brought about their own illness is cruel victim-blaming. The Mail has a long history of promoting the health benefits of daily alcohol consumption; but we are unaware of any article published by the Mail that categorically blames a woman's daily drinking for her death from breast cancer.

So is this myth-making about cannabis and psychosis a harmless form of tabloid titillation? We think not. When parents and even doctors become hysterical about a vulnerable individual using cannabis, attribute blame and have lots of arguments with them, for all their good intentions it may be making the situation worse. As we have seen, cannabis use is at worst one risk factor amongst many, and that cannabis containing CBD may in the short-term offer relief from psychotic symptoms and anxiety, even whilst it might make things worse in the long-term.

We are not saying that parents should just 'chill out' about their children using cannabis and especially not if they have a pre-disposition to mental health problems. However, people with schizophrenia struggle with a gap between their reality and the consensus reality, and often don't know who to trust. So to treat as delusional that person's valid experiences that cannabis helps ease their symptoms is not going to help. Research shows that the stress of criticism and stigma within the family and in the wider social environment worsens the course of schizophrenia, and can lead to suicide, whereas a stable, warm environment can improve the prognosis and protect against suicide.

Secondly, the media frenzy over cannabis and psychosis has had harmful and counterproductive political consequences. When he was Home Secretary, David Blunkett was brave enough to listen to what experts had been saying for decades, ignore hostility in the press, and downgrade cannabis to Class C. Following this move, cannabis use continued to decline steadily, (legal classification having no significant impact on cannabis use), the Home Office celebrated saving 199,000 hours of police time, whilst fewer people suffered the harms of criminalisation. However, from the announcement of reclassification onwards, the Mail and several other newspapers produced a stream of spurious articles about skunk cannabis and schizophrenia, alleging that Blunkett's move to "soften the law” was putting young people's mental health at risk. Predictably, the pressure was too much and in 2008 Jacqui Smith announced that she would put cannabis up to Class B again, a decision she now regrets.

Since then, the Mail has persisted in misleading their readership, even in 2011 asserting in a headline that "Just ONE cannabis joint can bring on schizophrenia”. To once again stress the gulf between this claim and reality, based on estimates discussed above it has been estimated that to prevent one case of schizophrenia in men aged 20 to 24, about 5,000 men would have to be prevented from ever smoking cannabis.

This year, a fascinating analysis was published of hospital admissions recorded for 'cannabis psychosis' over the brief period when cannabis was in Class C. Admissions fell when cannabis was made Class C and rose again when it became Class B. The lead author of this research, Ian Hamilton, points out that a causal link cannot be definitively made. Even so, after this finding, how can the Mail and others maintain their position that it is their heartfelt concern for the mental health of our children that justifies tough penalties for cannabis possession, and that those who argue against criminalisation recklessly endanger young people's minds? Whilst they dedicate pages to emotive anecdotes of cannabis victims, wildly misrepresent research on mice and report unpublished research when it can be distorted to fit their view, they unsurprisingly did not cover this peer-reviewed analysis.

t is bitterly ironic that those who set themselves up as a bastion against insanity-inducing cannabis may have some responsibility for the current situation, where vulnerable cannabis users only have access to the types of cannabis which pose the highest risks to mental health. The UK cannabis market has evolved under the pressures of tough enforcement. Instead of importing hashish and outdoor-grown cannabis, products high in cannabidiol (CBD), most is now grown indoors here, and contains far less CBD and much more of the psychosis-promoting THC. If the Mail wishes to crusade in the interests of families impacted by schizophrenia, they could instead support research into the potential use of CBD as an antipsychotic, one with none of the nasty side-effects of currently available options.

Tragically, it seems likely that the harmful consequences of promoting criminalisation, instead of education, to 'send messages' on drugs fall disproportionately on the very same people most vulnerable to any increased risk of psychosis that cannabis may produce. They are not the demographic of cannabis victims which the Mail focuses their sympathies on. A cannabis-using young person who is black, male, an immigrant or child of immigrants, lives in an urban area, and has an unstable home life has many of the risk factors for psychosis, and is precisely the demographic most likely to be arrested for cannabis possession. The disproportionate laws for which the Mail has lobbied, supposedly to reduce the harms of cannabis, just compound the harm falling on the most vulnerable.

DrugScience will critique, debunk and praise more drug-related stories in the media. We hope you will come back and read, and perhaps we'll see fewer nonsensical drug-related articles like this being published, and journalists using their talents to inform rather than mislead.

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