It is dangerous to build cannabis policy on paranoia
A few years ago Franjo Grotenhermen published an excellent article on the diagnosis of a new form of mental disorder, the cannabis induced psychological distress syndrome (CIPDS) in politicans. UNODC recently posted an article on the dangers of cannabis (Why should we care about cannabis?) on its website, which shows the symptoms of this sickness. It claims cannabis has become “more potent” than ever before, it can lead to acute “panic attacks, paranoia, psychotic symptoms and other negative acute effects”, can “precipitate psychosis in vulnerable individuals” and in smoked form it “puts users to increased risk of lung cancer”. They claim marijuana is more addictive than most users think: “treatment demand” for cannabis dependence is increasing in the US and Europe. It always amuses us how easy is to forge causal links where there is only correlation, to use arguments with obviously flawed logic or exagarate risks that are no more likely than a bolt from the blue. At the same time, the same people are blind when it comes to the obvious harms casued by the criminalization and stigmatization of millions of people in the name of health and security. So we decided to review the evidence behind these statements and put them into a rational policy context.
1) Cannabis potency
Indeed we can find many claims in the tabloid media that the potency of cannabis is increasing and “superskunk” is replacing weaker forms of pot. However, according to a 2004 study of the European Monitoring Center on Drugs and Drug Addiction, the overall potency of cannabis did not significantly increase in Europe, even if strong skunk has growing availability in the black market. According to a report of the UK Ministry of Home Affairs, “the mean/median potency of cannabis resin and imported herbal cannabis has remained largely unchanged over many years.” The proportion of home grown marijuana is increasing in the UK, but there is no sign that the potency of sinsemilla has been skyerocketing recently. There is no evidence that strong skunk is something new, we know that it has been available even decades ago. We have no evidence that the use of stronger cannabis induces different health risks than weaker forms of pot, or that users are not able to adjust the quantity to the expected effects. If there is a growing availability of stronger cannabis, it is a consequence of prohibition. Richard Cowan called this phenomenon the “iron law of prohibition”: traffickers try to distribute drugs in more concentrated and powerful forms in order to increase extraprofits and reduce the risks of arrest. During Alcohol Prohibition in the US, beer and wine was replaced by distilled liquors. The same is happening now with cannabis, cultivation becomes more and more hidden with advanced indoor technologies, home growers are able to produce more potent marijuana, so homegrown pot is replacing imported outdoor cannabis. There is no consumer protection, no standards for the quality of marijuana, so it is often polluted with chemicals. German researchers reported that street cannabis has been tainted with lead in the city of Leipzig recently, resulting in several hospital emergencies. Unfortunately UNODC is not concerned about people hospitalized with lead poisoning due to the lack of legal control mechanisms.
2) Cannabis and psychosis
Again, the claim that cannabis can induce schizophrenia is a half-truth in itself. Indeed, according to some researchers it can increase the risk of developing schizophrenia in vulnerable teens, but how can we draw political conclusions from this statement without telling the level and nature of this risk? Last year an article was published in The Lancet, the authors made a metha-analysis of available scientific literature on this subject and found 7 cohort studies containing original information. After carefully reviewing these articles and their metha-analysis, we can make the following conclusions. First, cannabis is neither necessary nor sufficient to cause schizophrenia in itself. According to our recent knowledge, schizophrenia is caused by the combined effect of genetical and environmental contributory factors, and cannabis may be one of the environmental contributors, but not enough in itself to cause schizophrenia. Similar correlation was discovered between alcohol and tobacco use and schizophrenia. There are environmental factors that increase the probability of schizophrenia much more, for example urban environment (according to a Swedish study, based on interviews with 4,4 million people, young people growing up in urban environment have 68-77% more chance to develop schizophrenia than young people living in villages – we also know that cannabis use is much higher in urban centers). Second, schizophrenia as a mental illnes evolves in the life age when many teenagers also start to experience with pot, so it is hard to decide what was first: marijuana use or the appearance of the first symptoms of schizophrenia. We know that many people who live with schizophrenia smoke pot because they believe (maybe wrongly) that it reduces the negative symptoms of their illness.
Third, if there is a certain causal relationship between schizophrenia and cannabis use, this relation does not seem to be statistically significant, because in a period when the level of cannabis use grew rapidly among teenagers, the prevalence of schizophrenia did not increase, what is more, even decreased according to some researchers. According to the Lancet article 800 schizophrenia cases could be prevented every year by eliminating marijuana use among teens in the UK. Even if we accept this controversial estimation, actually there are 6,2 million persons using cannabis every year in the country, so the risk of developing schizophrenia for a single user is 0,00125%. Fourth, if we accept that there is a relatively small risk of developing schizphrenia among a small group of vulnerable teens, it does not lead to the conclusion that we have to apply strict criminal sanctions against users. There is no evidence that criminal restrictions reduce the availability and use of the drug, or that the limited, controlled availability of cannabis for adults result in more use among high school students (a good example is the Netherlands).
In addition, it is especially dangerous to put teens who are vulnerable to schizophrenia into an authoritative, punitive environment, because that is also a risk factor of developing schizophrenia! So people who urge governments to restrict cannabis legislation based on the alleged shizophrenia-inducing effects of the plant actually reduce the chances of teens to avoid mental problems. Even the researchers whose studies are often cited by proponents of punitive drug policies do not think that criminalization is the solution. Dr. Zammit, author of the Lancet article said “It is not very helpful to mix the debate about the legal classification with the study findings”. According to Dr. David Fergusson, author of the New Zealand study, 95% of vulnerable teens in his research sample did not change or even increased use levels after being arrested, so criminalization had no deterrant effect (but probably caused significant harms). What is more, Dr. Jim van Os, author of an often cited Dutch study told the Guardian that the fact that cannabis could trigger psychosis in a small minority of people was a good reason to legalise it, not ban it. Indeed, it does not make sense to punish millions of adults to generate the illusion of keeping away a small group of vulnerable teens from using cannabis.
3) Cannabis and lung cancer:
It is true that the smoke of cannabis contains tars and other carcinogens, but there is no evidence that cannabis smoke causes lung cancer in the same way as tobacco smoking does. In vitro studies found pre-cancerous cells in the respiratory system after cannabis exposure, but only longitudinal human studies can establish the carcinogenic effects of cannabis smoking. According to Dr. Donald Tashkin, who conducted a research among 1209 cancer patients in California, cannabis smoking was not a contributing factor to develop cancer in itself, only if combined with tobacco smoking. Robert Melamede, a researcher of the University of Colorado published an interesting article on this subject in the Harm Reduction Journal, concluding that “both tobacco and cannabis smoke have similar properties chemically, their pharmacological activities differ greatly”, so this explains why tobacco smoke is more carcinogenic than cannabis smoke. In addition, currently available advanced vaporizer technologies can minimize the risks of different kinds of respiratory damage. According to some studies, cannabis may even play an important role in preventing and curing cancer in the future (more research is needed to prove its therapeutic applications).
4) Demand for cannabis treatment
The annual report of the EMCDDA claims that the treatment demand for cannabis related problems is on the rise in Europe. If we look at the growing global demand for cannabis, no wonder that more people need treatment if more people use pot, because a small percentage (around 10%) of those people who use cannabis develop dependence and/or other related problems, just like with other drugs. However, the so called Treatment Demand Indicator (TDI) of the EMCDDA can be misleading if we would like to learn more about the real need for treatment. Why? Because we don’t know how many people enter treatment voluntarily and how many of the “patients” are forced into treatment by the criminal justice system, the family, the school or the workplace. In fact we can suspect that the latter group contributed significantly to the reported increase of cannabis treatment demand. According to the EMCDDA report, 82% of people treated for opiate-related problems were daily users, but only 36% of people entering treatment for cannabis use as a primary problem used the drug in a daily basis. It is very suspicious that so great number of occasional marijuana users need treatment for cannabis problems, the only feasible explanation is that most of them enter treatment in order to avoid legal sanctions or other negative consequences. In the Netherlands, where police does not arrest cannabis users, 80% of patients treated with cannabis problems were daily smokers – we can assume that this is a more realistic indicator of treatment demand. Accordingly, there were only 6% increase in cannabis treatment demand in the Netherlands from 1996 to 2001, while there were 31% increase in Germany in the same period for instance, where possession for personal use is a criminal offence and there is no coffee shop system.
Altough we do not have exact data on the proportion of patients in voluntary and quasi-forced forms of treatment in Europe, we have data from some individual member states, for example from Hungary. According to current Hungarian drug legislation, offenders who possess small amounts of drugs for personal use can enter a 6 months treatment or prevention program as an alternative of criminal prosecution. We know from the annual report of the National Focal Point that approximately 90% of drug offenders are arrested for simple possession or acquisition in Hungary, so it is not surprising that more than 90% of people referred to treatment by the criminal justice system are occasional marijuana smokers. A recent study published in the Medical Weekly reported that more than half of the clients treated from 2001 to 2005 in a major Hungarian drug treatment center “had no treatment demand” – this means most of them were occasional marijuana users referred to treatment by the criminal justice system. At the same time, the government does not provide adequate funds for treating opiate addicts and prevent the spread of HIV and HCV among IDUs.
If we would like to make the international drug control system "fit for purpose" (this expression was used by a UNODC paper recently), first we should learn to rely on evidence and not on moral panic generated by the tabloid media.
Posted by Peter Sarosi