Reefer Madness: Cannabis, the Individual, and Public Policy TUOMAS E. TAHKO (www.ttahko.net) Published in Dale Jaquette (ed.) Cannabis: What Were We Just Talking About? (Oxford: Wiley-Blackwell, 2010), pp. 149–161. Introduction Why is cannabis not our drug of choice? On the face of it, cannabis seems so much better than legal drugs: it does not cause aggression, it gives the user no hangover, makes everything seem funny, and appears to be a lot healthier. Of course, at the dark end of the spectrum, cannabis is thought by some to act as a gateway drug, gets the user involved with criminals, causes social isolation and depression, and can lead to psychosis or even schizophrenia. Regardless of the supposed pros and cons of cannabis use, it certainly is the drug of choice for many. For instance, 22.7% of English and Welsh 16 to 29 year olds had used cannabis in the previous 12 months in 2001/2002. 1 The popularity of cannabis raises concerns that the use of less popular drugs perhaps does not, namely, how does the use of cannabis affect the quality of life and what sort of socio-economical impact does it have? Given the widespread use of cannabis, the implications that it may have should be taken under careful consideration. In what follows, I will examine both the adverse effects as well as potential benefits that cannabis use is likely to have in the light of recent research. The inquiry will be divided into two sections: the implications of cannabis use from the point of view of the individual on one hand, and from the point of view of society on the other. 1 Home Office, "British Crime Survey", http://www.homeoffice.gov.uk/rds/bcs1.html. 2 Cannabis and the Individual The use of any drug starts with the same thing: acquiring it. In the case of illegal drugs this part becomes considerably more complicated. Indeed, the legal status of cannabis is perhaps the most problematic aspect of cannabis use from the individual's point of view. The problem is not so much that cannabis is difficult to acquire. In fact, it appears that for most users the legal status of cannabis causes little or no hindrance in this regard: for instance, more than half of cannabis users in San Francisco are able to get hold of the drug within half a day. 2 What seems to be more problematic from the individual's point of view are the risks that the criminalisation of cannabis brings with it, specifically, the risk of getting caught and facing legal action. In San Francisco, twothirds of cannabis users have reported being afraid of these implications at least sometimes 3 , even if the actual risk of getting caught is rather small, with only 8% of the same sample group ever having faced legal action. Another concern for the cannabis user is that one may have to deal with criminals to acquire the drug, although this is unlikely to be a major concern. At least in San Francisco, the vast majority of cannabis users deal with their friends and the link to a dealer is established through trusted channels. 4 Accordingly, most cannabis users will never have any contact with the organised crime network which undoubtedly is behind a substantial portion of cannabis trafficking. In fact, by acquiring cannabis, or distributing the drug to one's friends, the individual becomes a criminal as well. Since the vast majority of cannabis users are likely to be normal, law-abiding citizens in other regards, the situation may seem rather disconcerting for many users. There are at least two 2 C. Reinarman, "Lineaments of Cannabis Culture: Rules Regulating Cannabis Use in Amsterdam and San Francisco," Contemporary Justice Review 10 (2007): 393-410. 3 Ibid., 34. 4 Ibid. 3 factors to consider here. Firstly, due to the extremely widespread use of cannabis, its criminalisation turns a substantial part of the population into ad hoc criminals. It is at least noteworthy that a substantial part of all criminals, perhaps even most criminals, are criminals strictly because they are cannabis users. Not to mention the problems that this causes for the law enforcement: due to the vast number of cannabis users, the police can do very little to maintain a credible threat for the cannabis user. In reality, small offences are often simply ignored. Secondly, while most cannabis users might never face any legal consequences, it is very possible that the credibility of the legal system diminishes in their eyes if it considers such a widely accepted activity as criminal. If the use of the drug is condoned by one's social circle, then its legal status may seem unjustified. Yet another issue regarding the source of cannabis is that at least some cannabis that originates from less reputable sources is likely to be of inferior quality. As an extreme example, in recent years in the UK, there have been concerns that cannabis may have been contaminated with small glass particles. 5 The motive for adding glass particles to cannabis is unclear, but it is likely to have something to do with increasing the weight of the product. This and other cases of contaminated cannabis are of course a direct consequence of the legal status of cannabis and the fact that some distributors of the drug will do anything to increase their profits. This obviously increases the risk of adverse health effects for the end-user. Effects on health are certainly one of the major concerns for cannabis users, and also for society more generally due to public health implications, so some discussion about these issues is necessary. Folk knowledge among cannabis users suggests that it 5 Public Health Link, "Update on seizures of cannabis contaminated with glass particles," 2007, http://www.nelm.nhs.uk/en/NeLM-Area/News/490687/490847/490854/. 4 is, in general, considerably healthier than either alcohol or tobacco, but rigorous studies especially into the long term effects of cannabis are still scarce. The acute health effects of cannabis, however, are fairly well documented. Because of the low toxicity of cannabis, the major risks are either derivative, i.e. increased accident-proneness, or psychological. A survey of the first is not necessary in this connection; I take it that any responsible drug user will be aware that for instance driving under the influence is not advisable. There have been a number of studies about the effects of cannabis on driving performance and it is not surprising that it will increase the risk of accidents, although considerably less than alcohol does. 6 In any case, this is not something that will be a major concern from the point of view of the individual, since it is easily avoided. As acute effects go, the only other notable adverse effects are perhaps occasional anxiety, panic attacks and paranoia. 7 The effects of chronic cannabis use on health are much more difficult to assess. This is partly because the medical histories often include the use of other drugs, and partly because heavy cannabis users often come from socio-economic groups that are at higher risk to begin with, so the effects of cannabis are difficult to isolate. 8 In any case, 6 E.g. M. N. Bates & T. A. Blakely, "Role of cannabis in motor vehicle crashes," Epidemiologic Reviews 21 (1999): 222–232; M. Asbridge, C. Poulin, & A. Donato, "Motor vehicle collision risk and driving under the influence of cannabis: Evidence from adolescents in Atlantic Canada," Accident Analysis and Prevention 37 (2005): 1025–1034; A. Smiley, "Marijuana: On road and driving simulator studies," in The health effects of cannabis, ed. H. Kalant et al. (Toronto: Centre for Addiction and Mental Health, 1999), 173-191; W. Hall, "The adverse health effects of cannabis use: What are they, and what are their implications for policy?," International Journal of Drug Policy 20 (2009): 458-466. 7 W. D. Hall & R. L. Pacula, Cannabis use and dependence: Public health and public policy (Cambridge, UK: Cambridge University Press, 2003), 38. 8 J. Macleod, et al., "Psychological and social sequelae of cannabis and other illicit drug use by young people: A systematic review of longitudinal, general population studies," Lancet 363 (2004): 1579– 5 it appears that adverse psychological effects are the ones that users should be concerned about. Other adverse health effects that chronic cannabis use may have include a number of illnesses associated with the respiratory system. These illnesses are of course due to smoking cannabis, which is by far the most common method of using it. However, illnesses that are due to smoking could be avoided entirely by using a different method. It is clear that smoking cannabis increases the risk of certain illnesses of the respiratory system, such as chronic bronchitis, but in many cases the results have been mixed. 9 The same is true of the connection between cannabis and certain types of cancer; it seems at least that smoking tobacco carries greater risks. 10 While chronic cannabis smoking certainly has some adverse effects for the respiratory system, a health-conscious individual could avoid the majority of these by using alternative methods, such as oral administration. Given the relatively mild adverse effects that cannabis appears to have for one's physical health, the greatest risks are perhaps psychological. I would include cannabis dependence in this section as well, for it is well known that cannabis does not cause significant physical dependence. In fact, before the modern understanding of dependence emerged in the seventies, cannabis was simply considered not to cause dependence at all. 11 Cannabis dependence is however now recognized as the most common form of drug dependence after alcohol and tobacco in the USA and Australia, and it is cannabis dependence that is likely to be responsible for the amotivational 1588. 9 W. Hall, "The adverse health effects of cannabis use: What are they, and what are their implications for policy?," International Journal of Drug Policy 20 (2009): 458-466. 10 Ibid. 11 W. D. Hall & R. L. Pacula, Cannabis use and dependence: Public health and public policy (Cambridge, UK: Cambridge University Press, 2003), 71. 6 effects that are often associated with cannabis, although there is very little evidence that suggests that even chronic cannabis use would cause any type of unique amotivational syndrome. 12 One of the best known adverse effects of cannabis is that it impairs cognitive functions such as short term memory, so that there may be a risk that chronic use will cause permanent damage to cognitive faculties. Indeed, there is some proof that this is the case, but once again the adverse effects of cannabis would seem to pale when compared to those of alcohol: Cannabis use does not produce gross cognitive impairment like that seen in heavy consumers of alcohol. There is growing evidence, however, that longterm daily cannabis use produces more subtle impairments in memory and attention. Expert opinion is divided on the significance of these differences in cognitive performance. Some sceptics still argue that we cannot exclude the possibility that these differences indicate pre-existing differences in cognitive ability, differences in other drug use, or a failure to ensure abstinence from cannabis. Increasingly more commentators believe that there are real, if small, differences in cognitive functioning between longterm cannabis users and controls. They argue that recent better-controlled studies make the sceptics' explanation implausible. 13 It appears that at least heavy cannabis use is likely to cause some cognitive impairment, although it is less clear whether the reduced performance in certain 12 Ibid. 13 Ibid., 85. 7 laboratory tests will translate into any effects whatsoever in everyday life. This nevertheless seems to be a very widely accepted conclusion. 14 However, cannabis use, correctly or incorrectly, is also commonly associated with psychotic disorders and even schizophrenia. If there is any truth to the claims that cannabis can cause severe psychological problems such as these, then this is surely something that cannabis users should take into consideration. That cannabis could cause such disorders is not difficult to see, as it is after all a potent psychoactive substance. The key question is: how strong is the causal link between cannabis and psychotic disorders? At least in the case of schizophrenia, there appears to be a clear statistical link between cannabis use and the illness 15 , but the interpretation of this statistical link is controversial. 16 Isolating the effects of cannabis is one of the problems, but it is also possible that there is some type of a deviant causal link in effect. For instance, people who are at a risk to develop schizophrenia may be more likely to become regular cannabis users. A recent systematic review of the link between cannabis use and psychotic disorders suggests that the odds ratio for those who have ever used cannabis to develop a psychotic disorder is 1.4 [95% confidence interval: 1.20, 1.65]. 17 However, another study of alcohol, cannabis and tobacco use among Australians suggests that cannabis is not associated with anxiety or affective disorders whereas alcohol 14 See also N. Solowij, Cannabis and Cognitive Functioning (International Research Monographs in the Addictions) (Cambridge: Cambridge University Press, 1998). 15 S. Andreasson et al., "Cannabis and schizophrenia: A longitudinal study of Swedish conscripts," Lancet 2 (1987): 1483–1486. 16 W. D. Hall & R. L. Pacula, Cannabis use and dependence: Public health and public policy (Cambridge, UK: Cambridge University Press, 2003), 92-93. 17 T. H. Moore et al., "Cannabis use and risk of psychotic or affective mental health outcomes: A systematic review," Lancet 370 (2007): 319–328. 8 dependence and tobacco use are associated with both of these disorders. 18 Finally, a recent study conducted in Norway concludes rather paradoxically that there is no link between cannabis use and depression, but that it may increase suicidal ideation and suicide attempts in later life. 19 In light of these results, it is probably safe to conclude that using cannabis increases the risk of psychological problems at least slightly, but probably not significantly more than the use of alcohol and tobacco. The conclusion that we may draw at this point is that although there are various health risks associated with the use of cannabis, these seem to pale in comparison with the adverse health effects of alcohol and tobacco. While cannabis is by no means harmless, people with no previous health problems are relatively unlikely to suffer major adverse effects, at least if cannabis is used only occasionally. Perhaps the biggest risk is the possibility of some type of psychological addiction: cannabis is the third most common drug 'addiction' after alcohol and tobacco. Whether this is reason enough to abstain from cannabis use altogether is another question; a question which requires discussion concerning the potential benefits that the use of cannabis may have. There are a number of medicinal uses for cannabis that have received a fair amount of attention. These include the use of cannabis to treat glaucoma, as an appetite stimulant, to relieve chronic pain in AIDS and cancer patients, to alleviate seizure disorders, and so on. 20 However, these medicinal uses are hardly a reason to use 18 L. Degenhardt, W. Hall, M. Lynskey, "Alcohol, cannabis and tobacco use among Australians: a comparison of their associations with other drug use and use disorders, affective and anxiety disorders, and psychosis," Addiction 96 (2001): 1603-1614. 19 W. Pedersen, W, "Does cannabis use lead to depression and suicidal behaviours? A population-based longitudinal study," Acta Psychiatrica Scandinavica 118 (2008): 395–403. 20 M. L. Mathre, ed. Cannabis in Medical Practice: A Legal, Historical and Pharmacological Overview of the Therapeutic Use of Marijuana (Jefferson, NC: McFarland & Co Inc, 1997). 9 cannabis for the majority of the population. The question is whether the use of cannabis can be beneficial for a healthy individual. Unfortunately, this is where the availability of systematic academic studies ends. Any discussion of the topic that one is likely to encounter will be based on anecdotal evidence and will thus be of little value for any kind of rigorous investigation of the matter. One of the few attempts at a survey of the benefits of cannabis, at least that I am aware of, is by Bello 21 , which certainly lacks the rigour that one would hope to see in such a study and appears mainly to consist of statements of the following type: 'Regardless of the model used, marijuana resolves conflict by de-emphasizing extreme aggressiveness and stroking the receptive sides of human nature. This unification or balance, however, may be responsible for changes in goals and values. It is the healthy balancing nature of marijuana that is most beneficial to the individual and most threatening to modern society'. 22 But is there nothing that we can say about the potential benefits of cannabis that would not seem like the rambling of a devoted pothead? The manner in which I would like to engage with this question would be with the help of systematic interviews with cannabis users, but that is obviously not possible in this context. However, I believe that at least a few speculative remarks are in order. At the very least it can be said that for those who use drugs anyway, cannabis may be the least harmful choice – there is certainly good evidence to this effect. Given that very few individuals abstain from drug use entirely, this fact on its own constitutes a strong argument in favour of cannabis. Whether this is really a benefit of cannabis use is another question. If cannabis does have any actual benefits for a healthy individual, they are most likely to be of a 21 J. Bello, The Benefits of Marijuana: Physical, Psychological and Spiritual, 2 nd ed., (Susquehanna, PA: Lifeservices Press, 2000). 22 Ibid., 51. 10 psychological nature. There has been some research into the motives for using cannabis, although the questionnaires used in these studies may not be as accurate as we would like. 23 The results, as one might expect, suggest that cannabis use is primarily motivated either by hedonistic motives such as relaxation or entertainment, or by coping motives such as to reduce social anxiety or depression. What is more interesting is that these studies strongly suggest that the adverse psychological effects of cannabis are associated with coping motives. For instance, a study of young Swiss adults discovered that only cannabis users with coping motives manifested the typical adverse psychological effects associated with cannabis, whereas users with social motives did not differ from non-users in terms of psychological disorders. 24 This suggests that many of the adverse effects of cannabis may be due to previous psychological problems. It is not surprising that the use of drugs would only emphasise such previous problems. It would be interesting to examine how the subgroup of cannabis users whose motives are social or hedonistic differs from non-users, if at all. There is certainly at least a possibility that these individuals have better mental health than non-users. The problem is that any effect of this type would be masked by problem-users in studies that do not moderate for the motives of cannabis use – something that is lacking from nearly all studies. So, could it be that cannabis use may be beneficial for one's mental health? 23 E.g. J. D. Buckner et al., "Marijuana use motives and social anxiety among marijuana-using young adults," Addictive Behaviours 32 (2007): 2238-2252; J. Brodbeck et al., "Motives for cannabis use as a moderator variable of distress among young adults," Addictive Behaviours 32 (2007): 1537-1545; C. Lee et al., "Development and Preliminary Validation of a Comprehensive Marijuana Motives Questionnaire," Journal of Studies on Alcohol and Drugs 70 (2009): 279-287. 24 J. Brodbeck et al., "Motives for cannabis use as a moderator variable of distress among young adults," Addictive Behaviours 32 (2007): 1537-1545. 11 Anecdotal evidence may suggest such benefits, but before we see a rigorous study about this that adjusts for the motives of use as well as other background conditions such as previous mental health problems, it is difficult to answer this question. I suspect that some mental health benefits are indeed likely, but probably in a preventive capacity rather than as a cure for acute problems. Why would this be the case? Two things come to mind: firstly, cannabis makes you laugh, and laughing is certainly good for you; secondly, cannabis has an introspective element. Where alcohol numbs your mind, cannabis makes you aware of yourself, and this is surely the first step towards a healthy mind. Be that as it may, I shall conclude simply by recommending further research into the potential benefits of cannabis use - strong anecdotal evidence in favour of such benefits surely warrants the research. Cannabis and Society From the point of view of the society, it is difficult to see how the use of any drug could be beneficial. Even if there are individuals who use drugs in a manner beneficial to them, it is likely that any possible benefits will be very small compared to the harmful effects of drugs. Hence, the question becomes: what is the most effective way to reduce the harmful effects of drugs? Quite clearly, a total ban of all drugs will not be the solution. Humans have always used drugs and they will always find a way to do that, no matter what measures society takes. Perhaps the biggest problems concerning drugs from society's standpoint are adverse health effects and the cost of treatment. Crime is another major problem, whether in acquiring drugs or as a result of their effects. We have already discussed the health effects of cannabis in the previous section, so in this section we will mainly focus on ancillary effects, such as crime and social isolation. The obvious question is: which 12 policy is the most effective in countering the adverse effects of cannabis? With cannabis having recently been reclassified from class C to class B in the UK, meaning that the law once again allows up to five years imprisonment for possession of the drug, it seems that society there is fixed on the idea that a tough antimarijuana policy is the answer. However, the message to the public is mixed to say the least, since the reasons for moving cannabis from class B to class C are still as valid as they were in 2004 when the downgrading was done. In their report preceding the reclassification of cannabis to class B in January 2009, the Advisory Council on the Misuse of Drugs (ACMD) recommended that cannabis should remain in class C: [A]fter a most careful scrutiny of the totality of the available evidence, the majority of the Council's members consider – based on its harmfulness to individuals and society – that cannabis should remain a Class C substance. It is judged that the harmfulness of cannabis more closely equates with other Class C substances than with those currently classified as Class B [such as amphetamines]. 25 The ACMD issued 21 recommendations to the government concerning cannabis. The government accepted all but one of these recommendations, the remaining recommendation was that cannabis should remain in class C. While this is quite baffling, it is perhaps not surprising if the policy towards cannabis will never be quite as liberal in countries such as the UK as it is in countries like the Netherlands. For one thing, the increased measures being taken against tobacco smoking make it difficult to 25 Advisory Council on the Misuse of Drugs, "Cannabis: Classification and Public Health," 2008, http://drugs.homeoffice.gov.uk/publication-search/acmd/acmd-cannabis-report-2008 13 build a case for cannabis smoking, and no one can claim that cannabis would not cause any harm, so the case for legalising cannabis would need to be based on reduced harms. 26 Is there any research that would suggest reduced harms if cannabis were to be legalised, or at least decriminalised? One major question concerns the connection between the use of cannabis and other illegal drugs, i.e. the notorious 'gateway' hypothesis, suggesting that cannabis use leads to the use of more harmful drugs in later life. This hypothesis has received plenty of attention and the consensus seems to be that although there may be some truth to it, the usual story is vastly exaggerated. 27 Most notably, Cleveland & Wiebe 28 conclude that patterns of drug use appear to have more to do with genetically influenced developmental trajectories rather than there being any real 'gateway effect' at hand. Similarly, Choo et al 29 . discovered that students in Tennessee who are likely to move from cannabis to other drugs tend to be the ones who manifest certain previous risk factors as well as are subject to environmental factors which contribute to problematic behaviour. What little plausibility remains for the hypothesis is likely to be explained by the availability of other drugs: often the source of cannabis is also a source for other illicit drugs. What makes this interesting is that if cannabis were to be legalised, at least 26 See W. Hall, "The adverse health effects of cannabis use: What are they, and what are their implications for policy?," International Journal of Drug Policy 20 (2009): 458-466. 27 A. L. Bretteville-Jensen, H. O. Melberg, A. M. Jones, "Sequential patterns of drug use initiation Can we believe in the gateway theory?," Journal of Economic Analysis & Policy 8 (2008); T. Choo, S. Roh, M. Robinson, "Assessing the 'gateway hypothesis' among middle and high school students in Tennessee," Journal of Drug Issues 38 (2008): 467-492; H. H. Cleveland, R. P. Wiebe, "Understanding the association between adolescent marijuana use and later serious drug use: Gateway effect or developmental trajectory?," Development and Psychopathology 20 (2008): 615-632. 28 Ibid. 29 Ibid. 14 part of this effect might disappear due to natural market separation: in San Francisco the source of cannabis is over three times more likely to have other drugs available than the source of cannabis in Amsterdam, where cannabis is usually acquired from coffee shops. 30 Another factor to consider, which has not received quite so much attention, is social isolation. It is obvious that the legal status of cannabis encourages users to secrecy and forces them to abstain from using the drug in public. Some cannabis users may also have to hide their use from their friends and family due to the social unacceptability of cannabis use. Furthermore, because cannabis users may have to hide their habit, it can be difficult to seek assistance for any potential problems that a user might encounter, such as addiction. All this contributes towards social isolation, the consequences of which can be severe especially for those who would require help. Some aspects of this social isolation are beginning to take ludicrous forms: in May 2009 the Guardian reported that in these tough economic times, UK employers are starting to use drug tests to get rid of staff without having to pay redundancy fees. 31 Most often these drug tests will reveal cannabis use, as it can remain detectable several weeks after use. However, whether this has any effect on the efficiency of the employee is questionable at the very least. One move that could alleviate these problems is the Dutch coffee shop model, where cannabis may be used in an environment where it is condoned. 32 Accordingly, from the point of view of harm reduction, decriminalisation 30 C. Reinarman, "Lineaments of Cannabis Culture: Rules Regulating Cannabis Use in Amsterdam and San Francisco," Contemporary Justice Review 10 (2007): 393-410. 31 D. Taylor, "Rise in use of drug tests to sack staff without redundancy pay", The Guardian, May 18, 2009, Society section, http://www.guardian.co.uk/society/2009/may/18/drugs-testing-workplaceredundancy. 32 See A. J. Suissa, "Cannabis, social control and exclusion: the importance of social ties," International 15 might very well be a sensible policy. Indeed, the consensus among public health experts is that the tough policy towards cannabis which was set in the 1961 Drug Convention is utterly obsolete. For instance, one conclusion of the convention was that cannabis has no medical value, and this has certainly been disputed. 33 Reflecting these opinions, The Beckley Foundation's 2008 Global Cannabis Commission Report put forward the following recommendation: The principal aim of a cannabis control system should be to minimize any harms from cannabis use. In our view this means grudgingly allowing use and attempting to channel such use into less harmful patterns (e.g. by delaying onset of use until early adulthood, encouraging all users to avoid substantial daily use, driving a car after using, and smoking cannabis mixed with tobacco). 34 The same report speculates about potential methods to proceed accordingly. There are apparent problems that any government wishing to minimise the harms of cannabis use will face, perhaps the most obvious ones are the international agreements concerning drug prohibition, such as the 1961 Drug Convention. Any country that hopes to change the legal status of cannabis would somehow have to get around this. However, these problems can certainly be overcome, and they are, at any rate, merely Journal of Drug Policy 12 (2001): 385–396. 33 E.g. M. L. Mathre, ed. Cannabis in Medical Practice: A Legal, Historical and Pharmacological Overview of the Therapeutic Use of Marijuana (Jefferson, NC: McFarland & Co Inc, 1997). 34 The Beckley Foundation, "2008 Global Cannabis Commission Report", 183, http://www.beckleyfoundation.org/policy/cannabis_commission.html. 16 political problems. A common reply is that changing the legal status of cannabis would 'send the wrong message', but what is so wrong about minimising harms? Clearly the current drug policy is not doing its job: in 1998 the UN general assembly special session declared their 10-year plan to eliminate the use and production of illicit drugs. 35 However, as the 2008 World Drug Report clearly indicates, the production and use of illicit drugs, far from having been eliminated, has in fact increased significantly. 36 In the case of cannabis, the number of users has increased steadily since 1998 and was at an all time high of 166 million people in 2006/07, and has probably increased since. Despite the utter failure of the previous policy, the UN Commission on Narcotic Drugs that took place in March 2009 37 committed itself to essentially the same policy that it did a decade ago, with hardly any attention being given to cannabis and its 166 million users. In light of these facts, the whole idea of international agreements on drugs seems completely absurd, no good can come from repeating the same mistakes over and over again. Unsurprisingly, I wish to conclude by revoicing the opinion of public health experts and recommending an altogether novel approach towards cannabis. With the use of cannabis being more widespread than ever we must face the fact that it will probably never be eliminated and any policy that aims at eliminating its use will surely fail miserably. The only viable option is to adopt a harm reduction policy. It cannot be disputed that using cannabis is potentially harmful, but given the moderately tame 35 UN General Assembly, "Twentieth Special Session: World Drug Problem," http://www.un.org/ga/20special/. 36 UNODC, "World Drug Report 2008," http://www.unodc.org/unodc/en/data-and-analysis/WDR-2008.html. 37 UNODC, "2009 Commission on Narcotic Drugs," http://www.unodc.org/unodc/en/commissions/CND/session/52-draftresolutions.html. 17 adverse health effects that cannabis appears to have, we should perhaps be more concerned about what kind of social implications the legal status of the drug has. As I have demonstrated above, factors such as social isolation and the risk of facing legal action or plain persecution may be far more harmful than any potential adverse health effects. However, these problems are strictly a consequence of a failed drug policy that with a little political will could certainly be overcome. References Andreasson, S., Engstrom, A., Allebeck, P., & Rydberg, U., "Cannabis and schizophrenia: A longitudinal study of Swedish conscripts." Lancet 2 (1987): 1483–1486. Asbridge, M., Poulin, C., & Donato, A., "Motor vehicle collision risk and driving under the influence of cannabis: Evidence from adolescents in Atlantic Canada." Accident Analysis and Prevention 37 (2005): 1025–1034. Bates, M. N., & Blakely, T. A., "Role of cannabis in motor vehicle crashes." Epidemiologic Reviews 21 (1999): 222–232. Bello, J. The Benefits of Marijuana: Physical, Psychological and Spiritual, 2 nd ed. Susquehanna, PA: Lifeservices Press, 2000. Bretteville-Jensen, A. L., Melberg, H. O., Jones, A. M. "Sequential patterns of drug use initiation Can we believe in the gateway theory?" Journal of Economic Analysis & Policy 8 (2008). Brodbeck, J., Matter, M., Page, J., Moggi, F. "Motives for cannabis use as a moderator variable of distress among young adults." Addictive Behaviours 32 (2007): 1537-1545. Buckner, J. D., Bonn-Miller, M. O., Zvolensky, M. J., Schmidt, N. B. "Marijuana 18 use motives and social anxiety among marijuana-using young adults." Addictive Behaviours 32 (2007): 2238-2252. Choo, T., Roh, S., Robinson, M. "Assessing the 'gateway hypothesis' among middle and high school students in Tennessee." Journal of Drug Issues 38 (2008): 467-492. Cleveland, H., H., Wiebe, R., P. "Understanding the association between adolescent marijuana use and later serious drug use: Gateway effect or developmental trajectory?" Development and Psychopathology 20 (2008): 615632. Degenhardt, L., Hall, W., Lynskey, M. "Alcohol, cannabis and tobacco use among Australians: a comparison of their associations with other drug use and use disorders, affective and anxiety disorders, and psychosis." Addiction 96 (2001): 1603-1614. Hall, W. D., & Pacula, R. L. Cannabis use and dependence: Public health and public policy. Cambridge, UK: Cambridge University Press, 2003. Hall, W. "The adverse health effects of cannabis use: What are they, and what are their implications for policy?" International Journal of Drug Policy 20 (2009): 458-466. Lee, C. M., Neighbors, C., Hendershot, C. S., Grossbard, J. R. "Development and Preliminary Validation of a Comprehensive Marijuana Motives Questionnaire." Journal of Studies on Alcohol and Drugs 70 (2009): 279-287. Macleod, J., Oakes, R., Copello, A., Crome, I., Egger, M., Hickman, M., et al. "Psychological and social sequelae of cannabis and other illicit drug use by young people: A systematic review of longitudinal, general population studies." Lancet 363 (2004): 1579–1588. 19 Mathre, M. L., ed. Cannabis in Medical Practice: A Legal, Historical and Pharmacological Overview of the Therapeutic Use of Marijuana. Jefferson, NC: McFarland & Co Inc, 1997. Moore, T. H., Zammit, S., Lingford-Hughes, A., Barnes, T. R., Jones, P. B., Burke, M., et al. "Cannabis use and risk of psychotic or affective mental health outcomes: A systematic review." Lancet 370 (2007): 319–328. Smiley, A. "Marijuana: On road and driving simulator studies." In The health effects of cannabis, edited by H. Kalant, W. Corrigall,W. D. Hall, & R. Smart, 173-191. Toronto: Centre for Addiction and Mental Health, 1999. Solowij, N. Cannabis and Cognitive Functioning (International Research Monographs in the Addictions). Cambridge: Cambridge University Press, 1998. Suissa, A. J. "Cannabis, social control and exclusion: the importance of social ties." International Journal of Drug Policy 12 (2001): 385–396. Pedersen, W. "Does cannabis use lead to depression and suicidal behaviours? A population-based longitudinal study." Acta Psychiatrica Scandinavica 118 (2008): 395–403. Reinarman, C. "Lineaments of Cannabis Culture: Rules Regulating Cannabis Use in Amsterdam and San Francisco." Contemporary Justice Review 10 (2007): 393-410.