Dutch study finds mathematics results suffer most from dope consumption \u2013 findings sure to fuel debate over steps towards legalisation If you want to do well in your exams, especially maths, don\u2019t smoke dope.<\/p>\n
This is the finding of a unique study that is likely to be fiercely debated by those in favour of and those against the liberalisation of cannabis laws.<\/p>\n
Economists Olivier Marie of Maastricht University and Ulf Z\u00f6litz of IZA Bonn examined what happened in Maastricht in 2011 when the Dutch city allowed only Dutch, German and Belgian passport-holders access to the 13 coffee shops where cannabis was sold.<\/p>\n
The temporary restrictions were introduced because of fears that nationals from other countries, chiefly France and Luxembourg, were visiting the city simply to smoke drugs, which would tarnish its genteel image.<\/p>\n
After studying data on more than 54,000 course grades achieved by students from around the world who were enrolled at Maastricht University<\/b><\/a> before and after the restrictions were introduced, the economists came to a striking conclusion.<\/p>\n In a paper recently presented at the Royal Economic Society conference in Manchester they revealed that those who could no longer legally buy cannabis did better in their studies.\u00a0 The restrictions, the economists conclude, constrained consumption for some users, whose cognitive functioning improved as a result.<\/p>\n \u201cThe effects we find are large, consistent and statistically very significant,\u201d Marie told the Observer<\/i>.\u00a0 \u201cFor example, we estimate that students who were no longer able to buy cannabis legally were 5% more likely to pass courses.<\/p>\n The grade improvement this represents is about the same as having a qualified teacher and, more relevantly, similar to decreases in grades observed from reaching legal drinking age in the US.\u201d<\/p>\n For low performers, there was a larger effect on grades. They had a 7.6% better chance of passing their courses.\u00a0 Interestingly, Marie and Z\u00f6litz found the effects were even more pronounced when it came to particular disciplines.<\/p>\n \u201cThe policy effect is five times larger for courses requiring numerical\/mathematical skills,\u201d the pair write.This, they argue, is not that surprising.\u00a0 \u201cIn line with how THC consumption affects cognitive functioning, we find that performance gains are larger for courses that require more numerical\/mathematical skills,\u201d Marie said.\u00a0 THC \u2013 tetrahydrocannabinol \u2013 is the active ingredient in skunk cannabis<\/b><\/a>, which some studies have linked with psychosis.<\/p>\n The ground breaking research comes at a significant moment.\u00a0 The clamour for liberalisation of cannabis laws is growing.<\/p>\n In Germany, Berlin is considering opening the country\u2019s first legal cannabis shop. Uruguay plans to be the first nation in the world to fully legalise<\/a> all aspects of the cannabis trade. In the US, more than 20 states now allow medical marijuana use, while recreational consumption has become legal in Alaska<\/b><\/a>, Oregon, Washington and Colorado<\/b><\/a>.<\/p>\n But, as Marie and Z\u00f6litz observe in their paper: \u201cWith scarce empirical evidence on its societal impact, these policies are mainly being implemented without governments knowing about their potential impact.<\/p>\n \u201cWe think this newfound effect on productivity from a change in legal access to cannabis is not negligible and should be, at least in the short run, politically relevant for any societal drug legalisation and prohibition\u00a0 decision-making,\u201d Marie said. \u201cIn the bigger picture, our findings also indicate that soft drug consumption behaviour is affected by their legal accessibility, which has not been causally demonstrated before.\u201d<\/p>\n The research is likely to be seized upon by anti-legalisation campaigners.\u00a0 But Marie was at pains to say the research should simply be used to raise awareness of an often overlooked aspect of drug use: its impact on the individual\u2019s cognitive ability.\u00a0 \u201cIf marijuana is legalised like it is in many states in the US, we should at least inform consumers about the negative consequences of their drug choices.\u201d<\/p>\n It will also feed into the debate about THC levels in cannabis, which are becoming ever stronger. Levels of THC in marijuana sold in Maastricht\u2019s coffee shops are around double those in the US. \u201cConsidering the massive impact on cognitive performance high levels of THC have, I think it is reasonable to at least inform young users much more on consequences of consuming such products as compared with that of having a beer or pure vodka,\u201d Marie said.\u00a0 History suggests that prohibition often results in the illicit drug or alcohol trade producing ever stronger products.<\/p>\n Campaigners for liberalisation argue that it could help bring THC levels down and allow users to know what they are buying. The authors concede that their findings could turn out to be different if they were to replicate their study in a country that did not have restrictions on cannabis use.\u00a0 Marie said his work had helped inform his discussions with his teenage son.\u00a0 \u201cI have a 13-year old boy and I do extensively share this with him as a precautionary measure so that he can make the best informed choice if he is faced with the decision of whether to consume cannabis or not.\u201d<\/p>\n