HESA Committee Report
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MARIJUANA'S HEALTH RISKS AND HARMSIntroductionOn 29 April 2014, the House of Commons Standing Committee on Health (“the Committee”) passed a motion agreeing to undertake a study of no more than five meetings examining the scientific evidence related to the health risks and harms associated with the use of marijuana.[1] The Committee further agreed that the study would focus in particular on the state of knowledge around the health risks of marijuana use, including its addiction potential and effects on the developing brain, as well as the level of awareness among Canadians regarding the health risks and harms associated with marijuana use.[2] During the course of its five-meeting study, the Committee heard from numerous witnesses, including government officials, representatives of the medical profession and recognized experts with peer-reviewed publications in medical and scientific journals. This report summarizes testimony from these hearings and identifies possible ways that the federal government could continue to work towards reducing the health risks and harms associated with marijuana use. Overview of Marijuana and its Use in CanadaA. What is Marijuana?Marijuana is the common name for Cannabis sativa, a hemp plant that grows throughout temperate and tropical climates.[3] The leaves and flowering tops of C. sativa plants contain at least 489 distinct compounds.[4] Among these compounds, delta-9-tetrahydrocannabinol (delta-9-THC or THC) is responsible for many, if not most, of the euphoric and addictive effects of cannabis, stimulating the cannabinoid 1 (CB1) and cannabinoid 2 (CB2) receptors of the endocannabinoid (eCB) system.[5] The eCB system is a lipid signalling system that plays a role in regulating a number of physiological as well as pathophysiological processes in humans, such as neural development, immune function, inflammation, appetite, metabolism and energy homeostasis, cardiovascular function, digestion, bone development and bone density, synaptic plasticity and learning, pain, reproduction, psychiatric disease, psychomotor behaviour, memory, wake and sleep cycles, and the regulation of stress and emotional states.[6] The plant also contains other cannabinoids, such as cannabinol, cannabidiol and cannabichromene, which are present in lesser amounts and have fewer, if any, psychotropic properties.[7] There are many different strains of C. sativa and their cannabinoid content varies based on a number of factors including soil and climate conditions, as well as cultivation techniques.[8] Most of the current scientific research available focuses on plant strains that contain high levels of THC and cannabidiol (CBD), whereas less is known about the effects of other plant strains.[9] The Committee heard that the marijuana available in Canada today has a higher THC content than marijuana available in the past. According to a Health Canada official who appeared before the Committee, the THC content in marijuana increased steadily between 1988 and 2010 based upon data from Health Canada’s drug analysis service, a trend that has also been seen in other jurisdictions such as Europe and the United States.[10] Data from the United States indicates that the THC content of marijuana increased from approximately 1% in the 1980s to between 10% and11% in 2011, whereas marijuana cultivated indoors on the west coast of Canada can have a THC content of upwards of 30%.[11] A Health Canada official indicated that greater mental and physical harms could potentially result from the use of marijuana with higher levels of THC.[12] B. Prevalence of Marijuana Use in Canada1. General PopulationAccording to an official from Health Canada, data from the 2012 Canadian Alcohol and Drug Use Monitoring Survey (CADUMS) shows that marijuana is the most commonly used illicit substance in Canada.[13] In 2012, 10.2% of the Canadian population reported using marijuana in the past year, with men nearly twice as likely to report marijuana use in comparison to women.[14] Meanwhile, 41.5% of Canadians have reported using cannabis at least once in their lifetime.[15] Approximately a quarter of Canadians who reported using cannabis in the last three months are considered to be chronic users who use cannabis on a daily basis.[16] Results of the Canadian Community Health Survey showed that approximately 1% of Canadian adults aged 25 to 64 met the criteria for abuse or dependence in 2012.[17] A written submission provided to the Committee by Dr. Perry Kendall indicated that, based upon the 2011 CADUMS data, approximately 17.7% of the Canadian population aged 15 or older who used cannabis in the past year did so for medical purposes.[18] Approximately 50% of individuals who used cannabis for medical purposes did so to relieve chronic pain caused by conditions such as arthritis, back pain and migraines, while the remaining half used cannabis for one of a variety of conditions that include insomnia, depression and anxiety.[19] 2. YouthThe Committee heard that the rate of marijuana use among youth is twice as high as that of adults, with 20.3% of Canadian youth reporting past-year use in 2012.[20] The average age of initiation of use among youth has remained unchanged over the past seven years at approximately 15.6 years.[21] A Public Health Agency of Canada (PHAC) survey that examined health behaviour in school-aged children in 2009–2010 found that between 10% and 12% of youth in grades 9 and 10 reported using marijuana three or more times in the past 30 days.[22] In addition, the Committee heard that a recent UNICEF study found that Canadian youth aged 11 to 15 are among the highest users of marijuana compared to their peers in other developed countries, with 28% reporting using cannabis at least once in the past year.[23] According to the Canadian Community Health Survey, over 5% of young Canadians aged 15 to 24 met the criteria for cannabis abuse or dependence in 2012.[24] C. Perceptions of the Health Risks and Harms of Marijuana Use among CanadiansWitnesses appearing before the Committee explained that Canadians have a lack of awareness about the health risks and harms associated with the use of marijuana, viewing it instead as a benign substance. An opinion survey conducted by the federal government’s National Anti-Drug Strategy (NADS) found that while both parents and youth are aware of the risks and harms of drugs such as cocaine, crack, ecstasy, and crystal meth, very few identified marijuana as being harmful.[25] PHAC’s health behaviour in school-aged children study also found that youth in grades 9 and 10 felt that there were slight or no potential health risks associated with the use of the drug.[26] A representative from the Canadian Centre on Substance Abuse (CCSA) explained that a survey conducted by the organization found that Canadian youth are very confused about the effects of cannabis use.[27] Some individuals who participated in the survey believed that cannabis helps improve their focus at school and that the drug could prevent or cure cancer. Youth surveyed were also uncertain as to whether cannabis improves or impairs driving performance, and believed that smoking marijuana before driving was not as dangerous as drinking and driving. Finally, the youth who were interviewed also saw cannabis as a natural product and therefore did not think of it as a drug. The Committee heard from a Health Canada official that the availability of medical marijuana in Canada and debates surrounding legalization in the United States may have contributed to confusion about the nature and effects of cannabis.[28] Meanwhile, a representative from the Royal Canadian Mounted Police (RCMP) indicated that a 2013 study by the Canadian Council of Motor Transport Administrators found that though the individuals surveyed generally agreed that alcohol impairs a person’s ability to drive a motor vehicle, only 68% felt that cannabis impairs driving ability.[29] Furthermore, while the majority recognized that a driver could be charged for alcohol-impaired driving, 26% of people did not believe that a driver could be charged for driving while impaired by cannabis. Finally, the Committee heard that the high rates of marijuana use among Canadians may be attributable to the perception that marijuana is a substance without any negative effects. One witness explained that in a survey of adults in three countries, Canadians were more likely to view cannabis as harmless and were more likely to have tried cannabis than adults in Sweden or Finland.[30] A survey of American senior high school students also found that there was an increase in marijuana smoking rates from 2.4% to 6.5% between 1993 and 2013, which was associated with a decline in the percentage (from 70% to 40%) over the same period of senior high school students who believed that regular marijuana smoking was harmful.[31] However, several witnesses expressed concern about the gap between Canadians’ perception of marijuana as a benign substance and current and emerging scientific evidence about its health risks and harms, particularly as the latter relate to vulnerable population groups such as youth.[32] Consequently, the witnesses felt that there is a need to raise awareness about the current and emerging scientific evidence about the health risks and harms of marijuana.[33] D. Impact of Marijuana Use on the Health Care SystemThe Committee also received testimony about the impact marijuana use is having on health care systems across Canada. According to the CCSA’s 2014 National Treatment Indicators Report, cannabis is the second most commonly used illicit drug among individuals accessing publicly funded addiction treatment services.[34] A Health Canada official appearing before the Committee also indicated that hospital data from the Canadian Institute for Health Information (CIHI) demonstrate that there has been an increase in marijuana-related hospitalizations.[35] In 2007–2008, there were 598 cases[36] where marijuana was considered the principal cause of the hospitalization.[37] The number of cases increased to 908 in 2012–2013.[38] Data from CIHI also indicate that the total number of cases[39] where any diagnosis was related to marijuana use, which resulted in ambulatory care encounters, including emergency department visits that may have resulted in hospitalizations, increased from 11,869 in 2007–2008 to 20,751 in 2012–2013.[40] It is important to note that the number of marijuana-related cases that resulted in hospitalizations also includes hospitalization cases where day surgery was required, but it was unlikely that the day surgeries were related to marijuana use.[41] Another study based on 2002 data found that 0.3% of total hospitalizations in Canada could be attributed to cannabis use compared to 5.8% for alcohol use, 1.4% for the use of other illegal drugs and 10.3% for tobacco use.[42] Scientific Evidence Related to the Health Risks and Harms of Marijuana UseWitnesses appearing before the Committee summarized the current status of research related to the health risks and harms of marijuana use in a broad range of areas, including cognitive functioning and brain development; mental health and addiction; respiratory effects; cardiovascular disease; and motor vehicle accidents. This testimony, which also highlighted in particular how youth are at greater risk for these possible negative health effects, is outlined in the sections below. A. Cognitive Functioning and Brain DevelopmentAccording to a representative of the CCSA, the research is clear that there are negative impacts on cognitive function immediately upon using cannabis, or what is considered to be “acute use”.[43] Specifically, marijuana impairs concentration and decision-making abilities, reaction time, memory and executive functioning – abilities that are required to safely operate a vehicle or to pay attention in school or go to work. These cognitive functions are further impaired when cannabis use is combined with alcohol.[44] Dr. Meldon Kahan further detailed that, “there is a strong relationship between cannabis use and anxiety and mood disorders as well as suicidal ideation. Acute cannabis use can trigger anxiety and panic attacks.”[45] Dr. Zach Walsh also explained that these acute cognitive effects can vary considerably across individuals, with more profound cognitive effects being experienced by infrequent cannabis users rather than by regular users who have developed a tolerance for the drug.[46] The Committee learned that cognitive impairment from acute marijuana use can affect a person up to a month after using the drug. Professor Harold Kalant explained that among adults, these physical and mental effects usually disappear on cessation of use.[47] Dr. Kahan explained that for daily or chronic users, these cognitive deficits may continue to persist even after a period of abstinence, but that existing long-term studies were only observational in nature.[48] In addition, Dr. Walsh pointed out to the Committee that a comprehensive meta-analysis study had concluded that there were divergent views on the effects of long-term regular cannabis consumption on the neurocognitive functioning of users, noting, “cannabis use may lead to earlier age of onset of schizophrenia among some vulnerable individuals and may also lead to some worse outcomes among those with a history of psychotic disorders.”[49] With respect to youth, the Committee heard that emerging scientific evidence demonstrated that regular or chronic use, defined as more than one joint per week, has a long-term impact on the cognitive functioning of this population group.[50] In her appearance before the Committee, Dr. Andra Smith explained that her research comparing brain activity among young adults (aged 18 to 21) who are regular marijuana users to the brain activity of young adults who do not smoke marijuana regularly has found that young adults who regularly use marijuana have to recruit more regions of their brains to perform tasks.[51] Dr. Smith said that the need to recruit more regions of the brain to complete a task reflects compensation for deficits in other areas of the brain. Functional Magnetic Resonance Imaging (fMRI) used during the study revealed that the area of the brain most affected by marijuana use is the prefrontal cortex, the area of the brain responsible for executive cognitive functions, including decision making, planning, organizing behaviour, and setting and achieving goals, while inhibiting inappropriate responses and maintaining mental focus.[52] Deficits in the prefrontal cortex meant that study participants had to rely on other regions of the brain, such as the limbic system and/or posterior regions of the brain, to complete executive cognitive tasks, However, the Committee heard that these regions are not as well developed to undertake executive cognitive functions as the prefrontal cortex, and are considered to be the “emotional brain.”[53] The Committee heard that the impact of marijuana use on the prefrontal cortex of the brain was particularly significant in relation to youth, as this part of the brain undergoes key phases of neuronal development during adolescence. As marijuana use during this period hijacks the development of the prefrontal cortex, youth are therefore more vulnerable to the neurotoxic effects of marijuana use.[54] The Committee heard from some witnesses that epidemiological research also supports these findings with regards to youth.[55] For example, the “Dunedin Study” followed 1,037 individuals born in Dunedin, New Zealand in 1972–1973. The study included repeated interviews and examinations every two to three years throughout childhood. The most recent follow-up was conducted in 2010–2012 when the participants were aged 38. The study showed that individuals who began to use marijuana regularly showed losses in intellectual function at 13 years of age, including a drop in IQ of between 6 and 8 points.[56] These losses were greatest among participants who were the highest users of marijuana and individuals who had started smoking at an early age. These mental health effects resulted in more school dropouts, poorer social adjustment and a greater risk of depression later in life. However, Dr. Walsh pointed out in his appearance before the Committee that substantial concerns have been raised in various publications about the findings of the Dunedin Study, particularly that other factors besides marijuana use may have played a role in the changes in IQ levels reported in the study, such as socio-economic status and personality characteristics linked to rule breaking and anti-social behaviour.[57] Finally, the Committee learned that exposure to prenatal marijuana use also has an impact on the intellectual development of children, based upon the findings of the Ottawa Prenatal Prospective Study (OPPS), which followed groups of offspring of mothers who smoked cannabis during pregnancy and compared them to the offspring of mothers who smoked tobacco or did not smoke any substance at all from birth until young adulthood.[58] The OPPS found that children of mothers who smoked cannabis during pregnancy experienced mental effects beginning at school age that persisted throughout their growth and development and into their adult years. Though these mental changes were considered minor, they were sufficient to affect the children’s educational attainment. According to witnesses appearing before the Committee, these findings on the impact of marijuana use on the brain development of youth, as well as children prenatally exposed to marijuana, highlight the need to raise awareness about the risks and harms of marijuana use, particularly among youth and pregnant women.[59] B. Mental Health and Addiction1. Psychosis and SchizophreniaDr. Romina Mizrahi explained to the Committee that cannabis can be considered a possible contributor to the development of schizophrenia in genetically vulnerable population groups.[60] According to Dr. Mizrahi, well-replicated epidemiological studies have shown a two- to six-fold increase in the incidence of schizophrenia with early cannabis use. This increase in reported risk for psychosis was associated with use of cannabis before the age of 15 and was dependent upon the dose of cannabis. Dr. Mizrahi explained that, though not well understood, cannabis use and schizophrenia were linked through the eCB system in humans.[61] The eCB system plays a role in the development of schizophrenia through its regulation of the release of dopamine, a key neurotransmitter involved in schizophrenia. Meanwhile, cannabis also acts upon the CB1 and CB2 receptors of the eCB system to produce its physiological and psychological effects. In addition, the Committee heard that the eCB system undergoes significant changes during early life, which could potentially explain the sensitivity of adolescents under the age of 15 to cannabis, and the development of schizophrenia among individuals with an underlying genetic vulnerability for the disease. Another witness, Dr. Tony George, also pointed out that genetics plays a role in determining who is more susceptible to experiencing psychosis as a result of cannabis use, noting that individuals with the gene catechol-O-methyltransferase, which is present in approximately 36% of the general population, are 5 to 10 times more vulnerable to psychosis when using cannabis.[62] Finally, the Committee heard that social stress and other environmental factors can also influence the functioning of the eCB system, which in turn impacts how the eCB system responds to cannabis use, particularly in individuals at risk for the development of schizophrenia.[63] Dr. Mizrahi therefore concluded that “cannabis use, genetic vulnerability, social stress and other social and environmental risk factors interact in a complex age-dependent manner, leading to the observed epidemiological link between cannabis and schizophrenia.”[64] According to Dr. George, these research findings speak to the need for prevention efforts, including education and behavioural interventions targeted at individuals who are at particular risk for the development of psychosis or schizophrenia as a result of cannabis use.[65] However, both Dr. Mizrahi and Dr. Walsh also pointed out that the relationship between cannabis and psychosis is not clear-cut because while the THC content of the plant is known to produce psychotic effects, its other components such as cannabigerol (CBG) and cannabidiol (CBD) have been reported to have an anti-psychotic effect.[66] Consequently, the risks for psychosis associated with cannabis use may also vary by the type of cannabis used, including the ratio of THC to CBG and CBD in the plant.[67] 2. Anxiety and DepressionSeveral witnesses appearing before the Committee explained that the evidence linking marijuana use to anxiety and depression is mixed.[68] The Committee heard that some studies have reported a higher prevalence of anxiety disorders among heavier cannabis users. In addition, some studies have shown that marijuana use can create the risk for the development of anxiety and mood disorders, as well as suicidal thoughts.[69] In addition, panic responses are the most common side effect of cannabis use, particularly among naïve users.[70] However, other studies have reported decreased depression and anxiety amongst cannabis users. Anxiety relief is reported as the primary motivation for cannabis use.[71] 3. AddictionAccording to the Canadian Medical Association, addiction is a serious, relapsing chronic disease, and substance abuse is a complex behaviour influenced by many different factors.[72] One of these factors is the clear addictive properties of cannabis itself.[73] The Committee heard that between 7% and 10% of cannabis users meet the criteria for dependence, which consist of developing a tolerance for the drug; experiencing difficulties on withdrawal; having a persistent desire to cut down or control consumption; spending time obtaining, using and recovering from the effects of the drug; giving up important social, occupational and recreational activities because of drug use; and continuing use despite knowledge of the drug’s harmful effects.[74] According to Dr. Bernard Le Foll, though the percentage of individuals who develop marijuana dependence is relatively low, the percentage of individuals who experience problematic use of the substance during the course of their lifetime is high at 40%.[75] These individuals will experience difficulties in controlling their use of marijuana, but this problem is generally transitory and does not require treatment to be cured. In addition, the Committee heard that certain population groups are more at risk for developing a cannabis-use disorder. The Committee heard that while the risk of addiction among individuals who regularly use marijuana in the general population is 10%, this figure increases to 16% among adolescents who regularly use the drug.[76] Dr. Le Foll explained to the Committee that there is clear evidence that the younger the initiation of use, the higher the risk of dependence.[77] This risk is highest for individuals who initiate use before the age of 14 and gradually decrease use until the age of 18. Risk of dependence remains lowest if the initiation of cannabis begins after the age of 18. Furthermore, the Committee heard that individuals with mental illnesses experience high co-morbidity rates of cannabis dependence.[78] It is estimated that persons with a mental illness consume roughly 80% of all cannabis consumed in the United States.[79] The co-morbidity of these two conditions may be attributed to the fact that individuals with mental illness may be more vulnerable to developing an addiction, or they may self-medicate for their disorder. Alternatively, the drug could be creating the psychiatric condition, though evidence is not conclusive in this area. The Committee heard that individuals with mental illnesses, particularly those with schizophrenia, who are heavy, persistent users of cannabis, will also experience further impairment of their cognitive functioning.[80] Finally, with respect to whether cannabis use during adolescence results in the increased use of other addictive substances later in life, a phenomenon known as the “gateway hypothesis”, the Committee heard that epidemiological data have shown that a small minority of cannabis users will go on to use harder substances such as heroin (1%) and cocaine (4%).[81] One witness explained that this could be attributed to the neurobiological effect of early cannabis exposure.[82] However, other witnesses suggested that other factors also play a role in exposing users to harder substances. For example, the illegal status of cannabis means that users must purchase cannabis on the black market where they can be offered other harder substances.[83] Poverty can also play a role. C. Respiratory EffectsWitnesses explained to the Committee that there are risks to a person’s respiratory system as a result of smoking marijuana. Smoking marijuana results in the inhalation of carcinogens and carbon monoxide, which creates health risks similar or possibly greater than those that arise from smoking tobacco. The Committee heard that research shows that marijuana smoke is an irritant to the lungs, increasing the prevalence of bronchitis, cough and phlegm production.[84] According to Dr. Kevin Sabet, marijuana smoke also contains between 50% and 70% more carcinogens than tobacco smoke.[85] In addition, marijuana smoke is unfiltered and users take larger and deeper puffs, keeping the smoke in the lungs longer, which may result in earlier onset of negative respiratory effects.[86] However, the Committee heard that research evaluating the long-term effects of marijuana toxicity on the lungs remains limited because marijuana is often smoked in combination with tobacco, making a cause-effect relationship difficult to establish.[87] With respect to lung cancer, Dr. Kahan pointed to a long-term 40-year cohort study, published in 2013, of 50,000 males that found that regular cannabis smoking was associated with a two-fold increase in the risk of developing lung cancer, after controlling for cigarette smoking and other risk factors.[88] Yet other witnesses indicated that the research in this area is unclear and more studies are necessary.[89] D. Cardiovascular RisksWitnesses also spoke of the cardiovascular risks associated with smoking marijuana. According to Dr. Kahan, cannabis smoking causes acute physiological effects including elevations in blood pressure and heart rate, and blood vessel constriction.[90] In addition, he noted that there have been case reports of young people suffering heart attacks and strokes shortly after smoking cannabis. E. Cannabis Use and Motor Vehicle AccidentsThe Committee learned from witnesses that research has shown that cannabis, when consumed in sufficient quantities, impairs the cognitive and psychomotor skills required for the safe driving of motor vehicles.[91] Studies have shown that vehicle tracking, reaction time and attention are impaired when cannabis is consumed.[92] Mr. Mark Asbridge explained that the impact of cannabis use on driving impairment is greatest between one to two hours after acute use. The Committee heard that meta-analytical studies have shown that driving within one to two hours of acute cannabis use increases the risk of car crashes two-fold. In particular, cannabis use during this period is associated with more severe crashes involving injury and death. Mr. Asbridge explained that these findings are relevant given that surveys conducted in Canada, Australia and the United States have found that self-reported rates of driving under the influence of cannabis now surpass self-reported rates of drinking and driving.[93] Furthermore, 1 in 10 adults and 4 in 10 youths have reported driving under the influence of cannabis within one to two hours after use, the period when THC in cannabis is likely to impair driving performance.[94] In addition, the Committee heard from an Inspector from the RCMP that a 2011 report by the CCSA found that one-third of fatally injured drivers in Canada from 2000 to 2008 were drug-impaired and the most common drugs found in their system were Central Nervous System depressants, cannabis and stimulants.[95] Furthermore, the group most at risk for fatal motor vehicle accidents was drivers aged 16 to 24 and the drug of choice was cannabis.[96] The Committee also heard that many of the traffic fatalities related to drug use included multi-drug use and/or the use of cannabis in combination with alcohol.[97] However, Mr. Asbridge indicated that there are ongoing policy and research debates on the relationship between cannabis use and the risk of motor vehicle accidents.[98] He explained that while there appears to be a dose-response relationship between THC levels measured in the blood and the risk of a motor vehicle accident, there are debates on what levels of THC in the body can be considered legal impairment, because impairment is influenced by the exact timing of marijuana consumption in relation to the driving event. A representative of the RCMP further explained that THC levels in the blood will fall from 50 or 25 nanograms per millilitre to below 2.5 per milliliters within 160 minutes of cannabis use in approximately 90% of the population. Meanwhile, heavy users will have residual levels of 2.5 nanograms per millilitre as a result of past use.[99] In addition, Mr. Asbridge noted that there are ethical challenges associated with conducting research assessing the extent to which cannabis contributes to the risk of a motor vehicle accident because it also requires measuring the levels of marijuana use in drivers not involved in crashes through blood tests.[100] The Federal Role in Addressing the Health Risks and Harms of Marijuana UseOfficials from Health Canada appearing before the Committee outlined the federal government’s role in addressing the health risks and harms associated with marijuana use, including the regulation of recreational and medical use of marijuana under the Controlled Drugs and Substances Act (CDSA), and prevention approaches that focus on increasing knowledge and raising public awareness. Other witnesses presented ways in which the federal government could further its efforts in this area. This testimony is presented in the sections below. A. Marijuana Use and the Controlled Drugs and Substances ActAccording to a Health Canada official appearing before the Committee, the CDSA is Canada’s federal drug control statute, which provides a legislative basis for the control of substances that can alter mental processes and may cause harm to the health of an individual or society when abused or diverted into the illicit market.[101] The Act sets out offences in the form of direct prohibitions of many activities involving controlled substances, including production, possession, distribution, import or export of these substances. However, it does contain provisions that allow for access to these substances for legitimate medical, industrial or scientific purposes, while subjecting them to tight controls. As such, the Act has a dual purpose to protect public health and maintain public safety.[102] Substances controlled under the CDSA are grouped into six different schedules.[103] In determining whether a substance should be added to one of the schedules to the Act, Health Canada examines the following six factors: international requirements and trends related to scheduling; chemical and pharmacological similarly to other substances listed under the Act; addiction liability and potential for abuse; evidence of actual abuse in Canada and internationally; risk to personal and public health and safety; and its legitimate therapeutic, scientific, industrial or commercial uses.[104] C. sativa, its derivatives, preparations and similar synthetic preparations are listed under Schedule II of the CDSA, making its recreational use illegal in Canada. The official further explained that Canada’s regulation of marijuana as a controlled substance is in line with legislation in most other countries and its international obligations under three United Nations drug conventions. Moreover, the official noted that marijuana has been regulated as a controlled substance in Canada since 1923. Witnesses such as Dr. Kahan, Professor Kalant and Dr. Sabet do not support the legalization of marijuana because it would increase the health risks and harms associated with its use.[105] They suggested that the legalization of marijuana would increase its availability and lower its price, which would make its use more widespread. More widespread use in turn would increase the number of people experiencing negative health consequences of its use. For these witnesses, the legalization of tobacco and alcohol represent a case against the legalization of marijuana, as the higher health-related costs associated with use and abuse of these substances can be attributed to their widespread use within the general population.[106] Furthermore, the legal status of alcohol and tobacco does not prevent youth from gaining access to it, nor does it eliminate the black market for tobacco, where content remains unregulated. Dr. Sabet explained that experiences of legalization in other jurisdictions support this argument. For example, he pointed out that legalization of marijuana use in the City of Denver, Colorado in 2005 resulted in an increase in the rate of marijuana use, which is also higher than the average rate of use in areas of the United States where recreational marijuana use is prohibited.[107] Dr. Sabet’s presentation showed that past-month use in Denver increased from 9.6% in 2006–2008 to 12.2% in 2008–2010.[108] Meanwhile, past-month prevalence of marijuana use in the United States as a whole increased from 6% to 6.6% during the same period. Dr. Sabet explained that increased availability of marijuana in Colorado has resulted in unintentional toxic ingestions of marijuana by children, which resulted in admissions to the Children’s Hospital in Colorado.[109] His presentation also showed that between 2007 and 2011, there was an increase in the number of fatal car crashes, from 23 to 53, involving drivers testing positive for marijuana.[110] Dr. Kendall’s written submission to the Committee indicated that data from a World Health Organization survey showed that globally, drug use was not related to drug policy, as countries with stringent user-level illegal drug policies do not have lower levels of use than those with more liberal policies.[111] Dr. Evan Wood also pointed out that the illegal status of marijuana does not prevent youth from gaining access to the substance, as 80% of young people surveyed in the U.S. Monitoring of the Future Study suggested that cannabis is easy to obtain.[112] Professor Kalant also commented that: …the use of cannabis for pleasure comes at a cost, and society must ponder whether the pleasure is worth the cost…society as a whole must give careful thought to changes in policy that could increase the number and severity of health problems caused by use by its more vulnerable members, which, as I have pointed out, means its younger users.[113] Finally, Dr. Didier Jutras-Aswad suggested that the scheduling of cannabis under the CDSA should be reviewed to take into account the different contents of the plant, as cannabis strains that contain high levels of cannabinoids such as CBD and low levels of THC are much safer and less addictive than those with high levels of THC and low levels of CBD.[114] B. Marijuana Use for Medical PurposesUnder section 55(1) of the CDSA, the federal government grants access to marijuana for medical purposes to individuals who have the support of a health care provider through the Marihuana for Medical Purposes Regulations (MMPR), making it one of four countries to have a form of a medical marijuana regime.[115] Hilary Geller, Assistant Deputy Minister at Health Canada, explained to the Committee that the federal government enabled reasonable access to marijuana for medical purposes in response to a decision made by the courts. She further articulated that dried marijuana is not an approved drug or medicine in Canada and the department does not endorse its use.[116] She explained that, “…dried marijuana has not gone through the clinical trials, etc., and the rigorous process that is required for any other prescription medication in this country.”[117] Finally, she noted that the MMPR are new regulations introduced in June 2013. The Committee also learned from officials that there are two prescription drugs which contain cannabinoids that have been approved for medical use by Health Canada under the Food and Drugs Act: Sativex and Cesamet.[118] Sativex contains both THC and cannabidiol and is indicated as an adjunctive treatment for the relief of neuropathic pain for adults with multiple sclerosis. Meanwhile, Cesamet contains a synthetic cannabinoid and is used in the management of nausea and vomiting in patients undergoing chemotherapy.[119] As a result of the limited scientific evidence demonstrating the safety and effectiveness of smoked marijuana, physicians appearing before the Committee indicated that they did not support the use of dried, smoked marijuana for the treatment of medical conditions.[120] In particular, the Federation of Medical Regulatory Authorities indicated that it has remained opposed to the medical marijuana regime in Canada for the past 10 years because of the lack of clinical evidence in this area which, in their view, puts patients at risk.[121] The organization also explained that it does not support the new regulations introduced in June 2013, as they diminish the role of the physician in the scheme from attesting to the medical condition of patients to that of a signing authority for authorizing the use of medical marijuana by their patients. Producers who have been licensed by Health Canada under the MMPR have also presented their reservations about some of the health risks associated with smoking marijuana, including Canmart which, in its written submission to the Committee, stated, “While people across the country have varying opinions on the use of marijuana, the scientific evidence is clear that the use of THC by some youth with predisposition for schizophrenia and related disorders is detrimental to their health.”[122] To address these concerns about the safety and efficacy of medical marijuana use, witnesses recommended that evidence-based clinical guidelines for the medical use of marijuana be developed to help physicians make sound prescribing decisions.[123] In addition, Dr. Kahan also recommended that dosing limits be established under the new medical marijuana regulations.[124] He explained that distributors are currently selling cannabis strains with up to 30% THC content and under the new regulations, physicians are able to prescribe up to five grams of marijuana per day. From his perspective, these THC concentrations coupled with the dosage are excessive and pose a danger to patients. Instead, he recommended that the dose be limited to no more than 400 milligrams per day of cannabis with 9% THC content. Finally, the Committee heard from witnesses who suggested that there is a need for the federal government to provide support for research examining the safety and effectiveness of the medical use of marijuana, including a post-market surveillance program to evaluate the health outcomes of medical marijuana users in Canada.[125] C. Prevention Through Knowledge and Public AwarenessThe Committee heard that the federal government is addressing the health risks and harms associated with marijuana use by increasing knowledge and public awareness in this area. A Health Canada official explained that through the NADS, the Minister of Health is providing $11.5 million over five years to the CCSA to reduce drug use among youth, including support for research examining the impact of marijuana use on brain development and impaired driving.[126] The official further noted that the Minister is also engaging key stakeholders and experts to discuss scientific evidence related to the health effects of marijuana use by youth and identify strategies for raising awareness of the risks of marijuana use. The Committee also heard that strategies from successful public awareness campaigns targeted at reducing the use of hard street drugs could be used to inform new efforts to develop awareness campaigns for marijuana use. A representative from the RCMP explained that the organization has developed a strategy to help change public attitudes about impaired driving, which focuses in part on education and raising awareness about drug-impaired driving.[127] Activities under this strategy include engaging youth in discussions on both drug- and alcohol-impaired driving; coordinating national enforcement days against impaired driving; and supporting training and equipment to support drug-impaired driving investigations. Through NADS, the RCMP also engages in public outreach in relation to illegal marijuana use through public awareness programs such as Drug Abuse Resistance Education, the Aboriginal Shield Program, Racing Against Drugs, Kids and Drugs and Drug Endangered Children. Witnesses appearing before the Committee highlighted the importance of raising awareness of the potential health risks and harms of marijuana use as a key means of reducing the rate of marijuana use, as well as cannabis-impaired driving in Canada. As Dr. George explained, the Monitoring of the Future Study in the United States found that if the perception of harm among youth is increased, the rate of cannabis use decreases.[128] The Committee heard that public awareness campaigns addressed towards youth need to focus on accurate information on the health risks and harms of marijuana use to empower youth to make informed decisions about their well-being and future, rather than using scare tactics which have been shown to be less effective.[129] Witnesses also indicated that physicians, nurse practitioners and other primary care providers had a key role to play in raising awareness, as evidence suggests that adolescents are open to advice from their physician on substance abuse.[130] Finally, witnesses also noted that addressing substance abuse is a complex task that requires a multifactorial strategy that focuses on preventing drug abuse and dependence; increasing the availability of assessment, counselling and treatment services for individuals; and reducing the risks and harms of substance abuse.[131] Committee Observations and RecommendationsThe Committee’s study focused on examining scientific evidence related to the health risks and harms associated with marijuana use. In particular, the Committee was interested in learning about the impact of marijuana use on the developing brain of youth and the drug’s potential for addiction. Witnesses appearing before the Committee explained that current and emerging scientific evidence is demonstrating that youth are particularly at risk for the health risks and harms of marijuana use linked to impairment resulting from both acute and chronic use. The Committee also heard that prenatal exposure to marijuana can cause subtle mental effects in children beginning at three years of age, which are significant enough to affect educational attainment. Youth are also more vulnerable to addiction to cannabis than are adults: addiction rates for regular users in the general population are 10%, whereas for youth, they increase to 16%. For both youth and adults with a genetic pre-disposition to schizophrenia, cannabis, in addition to other genetic, environmental and social factors, is considered a possible contributor to the development of the disease. In addition to the known cognitive impairment associated with acute use, the study also revealed that chronic cannabis use may also result in respiratory effects, cardiovascular risks, anxiety and depression in some members of the population. Finally, the Committee heard that cannabis use increases the risk for a motor vehicle accident two-fold, if consumed one to two hours before driving. Despite these health risks and harms associated with use, the Committee heard that Canadians, and, in particular, youth, see cannabis as a benign substance and are confused about its health impacts. Moreover, witnesses explained that this perception contributes to the high rates of use among youth at 20.3% and among the general population at 10.2%. For witnesses, this trend was all the more worrying, given evidence suggesting that the potency of marijuana has increased substantially from 1% THC content in the 1980s to approximately 10% to 11% today. Given the gap between the current and emerging scientific evidence related to the impact of marijuana use on youth, witnesses highlighted the need for increased public awareness of its health risks and harms so youth and their parents could make informed choices. The Committee therefore recommends that: Recommendation 1 The Government of Canada work with relevant stakeholders and experts to develop a campaign to raise public awareness and knowledge of the risks and harms associated with marijuana use. Recommendation 2 The Government of Canada work with health professional organizations to increase their awareness of the scientific evidence related to the health risks and harms of marijuana use and promote the development and dissemination of tools to support these organizations’ efforts to prevent, manage and treat drug abuse. Recommendation 3 The Government of Canada continue to support, in collaboration with the provinces and territories and key stakeholders, strategies for the prevention of drug-impaired driving through the RCMP Impaired Driving Strategy Recommendation 4 The Government of Canada continue to fund research aimed at improving the understanding of the short- and long-term harms related to marijuana use, and, in particular, its relationship to the development of addiction in vulnerable population groups, such as youth and individuals with mental illnesses. The Committee’s study also revealed that some physicians appearing before the Committee do not support the medical use of dried marijuana as allowed for under the federal Marihuana for Medical Purposes Regulations. To facilitate access to medical marijuana in Canada, as mandated by court rulings, the Committee was told that there is a need for evidence-based clinical guidelines for marijuana use; more research into its clinical effectiveness; post-market surveillance of patient outcomes; and monitoring of physician prescribing behaviour.[132] [1] House of Commons Standing Committee on Health (HESA), Minutes of Proceedings, 2nd Session, 41st Parliament, 29 April 2014. [2] Ibid. [3] Health Canada, “Information for Health Care Professionals: Cannabis (marihuana, marijuana) and the cannabinoids,” February 2013. [4] Ibid. [5] HESA, Evidence, 2nd Session, 41st Parliament, 8 May 2014, 0850 (Dr. Bernard Le Foll, Professor, University of Toronto, as an Individual). [6] Health Canada, “Information for Health Care Professionals: Cannabis (marihuana, marijuana) and the cannabinoids,” February 2013. [7] Ibid. [8] Ibid. [10] HESA, Evidence, 2nd Session, 41st Parliament, 1 May 2014, 0845 (Hilary Geller, Assistant Deputy Minister, Healthy Environments and Consumer Safety Branch, Department of Health) [11] HESA, Evidence, 2nd Session, 41st Parliament, 6 May 2014, 0850 (Dr. Kevin Sabet, Executive Director, Smart Approaches to Marijuana). [13] Ibid. [14] Ibid. [15] Health Canada, Canadian Alcohol and Drug Use Monitoring Survey (CADUMS), Summary of Results for 2012). [16] HESA, Evidence, 2nd Session, 41st Parliament, 6 May 2014, 0900 (Michel Perron, Chief Executive Officer, Canadian Centre on Substance Abuse). [17] Ibid, 0905. [18] Dr. Perry Kendall, Public Health Officer, Government of British Columbia, “Cannabis Related Benefits and Harms: Information to Assist in Decision Making about Cannabis Policy,” 21 May 2014. [19] Ibid. [21] Dr. Perry Kendall, “Cannabis Related Benefits and Harms: Information to Assist in Decision Making about Cannabis Policy,” 21 May 2014. [22] Ibid. [23] HESA, Evidence, 2nd Session, 41st Parliament, 1 May 2014, 0950 (Dr. Meldon Kahan, Medical Director, Women’s College Hospital, as an Individual). [26] Ibid. [29] Inspector J.R. Taplin, “Speaking Notes for Insp. J.R. TAPLIN: Appearance before the House of Commons Standing Committee on Health, Topic: Marijuana: Health Risks and Harms,” 27 May 2014. [31] Ibid, 0955. [32] HESA, Evidence, 2nd Session, 41st Parliament, 6 May 2014, 0905 (Michel Perron) and 0940 (Dr. Kevin Sabet); HESA, Evidence, 2nd Session, 41st Parliament, 1 May 2014, 0850 (Hilary Geller). [33] Ibid. [35] Ibid. [36] It is important to note that the number of cases represents admissions or care encounters, not unique patients, so the same individual can be counted more than once in a year. [37] Canadian Institute of Health Information (CIHI) “CIHI Data on Marijuana-related Hospitalizations and Ambulatory Care Encounters (including Emergency Departments)” submitted to the Committee by Health Canada on 12 May 2014. [38] Ibid. [39] It is important to note that the number of cases represents admissions or care encounters, not unique patients, so the same individual can be counted more than once in a year. [40] Canadian Institute of Health Information (CIHI) “CIHI Data on Marijuana-related Hospitalizations and Ambulatory Care Encounters (including Emergency Departments)” submitted to the Committee by Health Canada on 12 May 2014. [41] Ibid. [42] Dr. Perry Kendall, “Cannabis Related Benefits and Harms: Information to Assist in Decision Making about Cannabis Policy,” submitted to the Committee on 21 May 2014. [44] Ibid. 0930. [46] HESA, Evidence, 2nd Session, 41st Parliament, 13 May 2014, 0940 (Dr. Zach Walsh, Associate Professor, University of British Columbia, as an Individual). [47] HESA, Evidence, 2nd Session, 41st Parliament, 1 May 2014, 1000 (Professor Harold Kalant, University of Toronto, as an Individual). [50] HESA, Evidence, 2nd Session, 41st Parliament, 6 May 2014, 0850 (Dr. Andra Smith, Associate Professor, University of Ottawa). [51] Ibid. [52] Ibid. [53] Ibid. [54] Ibid. [55] HESA, Evidence, 2nd Session, 41st Parliament, 1 May 2014, 0950 (Dr.Meldon Kahan); HESA, Evidence, 2nd Session, 41st Parliament, 6 May 2014, 0850 (Dr. Andra Smith); HESA, Evidence, 2nd Session, 41st Parliament, 6 May 2014, 0910 (Dr. Kevin Sabet). [58] HESA, Evidence, 2nd Session, 41st Parliament, 1 May 2014, 1000 (Professor Harold Kalant); HESA, Evidence, 2nd Session, 41st Parliament, 6 May 2014, 0850 (Dr. Andra Smith). [59] HESA, Evidence, 2nd Session, 41st Parliament, 1 May 2014, 1000 (Professor Harold Kalant); HESA, Evidence, 2nd Session, 41st Parliament, 6 May 2014, 0850 (Dr. Andra Smith and Michel Perron); HESA, Evidence, 2nd Session, 41st Parliament, 6 May 2014, 0910 (Dr. Kevin Sabet). [60] HESA, Evidence, 2nd Session of the 41st Parliament, 8 May 2014, 0910 (Dr. Romina Mizrahi, Assistant Professor of Psychiatry at the University of Toronto, as an Individual). [61] Ibid. [62] HESA, Evidence, 2nd Session of the 41st Parliament, 8 May 2014, 0925 (Dr. Tony George, Professor of Psychiatry, University of Toronto, as an Individual). [64] Ibid. [66] HESA, Evidence, 2nd Session of the 41st Parliament, 8 May 2014, 0915 (Dr. Romina Mizrahi); HESA, Evidence, 2nd Session, 41st Parliament, 13 May 2014, 0850 (Dr. Zach Walsh). [68] HESA, Evidence, 2nd Session, 41st Parliament, 6 May 2014, 0900 (Michel Perron); HESA, Evidence, 2nd Session, 41st Parliament, 13 May 2014, 0950 (Dr. Zach Walsh). [69] HESA, Evidence, 2nd Session, 41st Parliament, 13 May 2014, 0855 (Dr. Zach Walsh); HESA, Evidence, 2nd Session, 41st Parliament, 1 May 2014, 0950 (Dr. Meldon Kahan). [70] Ibid. [72] Canadian Medical Association, “The Health Risks and Harms Associated with the Use of Marijuana,” submitted to the Committee on 27 May 2014. [74] HESA, Evidence, 2nd Session of the 41st Parliament, 8 May 2014, 0855 (Dr. Bernard Le Foll); HESA, Evidence, 2nd Session, 41st Parliament, 1 May 2014, 0950 (Dr. Meldon Kahan). [78] Ibid, 0905. [79] Ibid. [81] HESA, Evidence, 2nd Session, 41st Parliament, 27 May 2014, 1020 (Dr. Didier Jutras-Aswad, Assistant Clinical Professor, Psychiatric Department, Université de Montréal, as an Individual); HESA, Evidence, 2nd Session, 41st Parliament, 13 May 2014, 0845 (Philippe Lucas). [85] Ibid. 0935 [86] Ibid. Canadian Centre on Substance Abuse, “Clearing the Smoke on Cannabis Series: Highlights,” April 2013, submitted to the HESA on 6 May 2014. [89] HESA, Evidence, 2nd Session, 41st Parliament, 6 May 2014, 0905 (Michel Perron) and 0935 (Dr. Kevin Sabet). [91] HESA, Evidence, 2nd Session, 41st Parliament, 27 May 2014, 0930 (Mark Asbridge, Associate Professor, Dalhousie University, as an Individual). [92] Ibid. [93] Ibid. [94] Ibid. [95] HESA, Evidence, 2nd Session, 41st Parliament, 27 May 2014, 0845 (Inspector Jamie Taplin, Royal Canadian Mounted Police (RCMP)) [96] Ibid [97] Ibid. 0850. [98] Ibid. 0845 (Mark Asbridge). [99] Ibid. 0910 (Darcy Smith, General Manager, National Forensic Services, RCMP). [100] Ibid.0935 (Mark Asbridge). [102] Ibid. [103] Ibid. [104] Ibid. [105] HESA, Evidence, 2nd Session, 41st Parliament, 1 May 2014, 1030 (Dr. Meldon Kahan) and 1025 (Professor Harold Kalant));HESA, Evidence, 2nd Session, 41st Parliament, 6 May 2014, 0940 (Dr. Kevin Sabet). [106] Ibid. [107] HESA, Evidence, 2nd Session, 41st Parliament, 6 May 2014, 1030 (Dr. Kevin Sabet) and Kevin A. Sabet, Ph.D., “Reefer Sanity: Seven Great Myths About Marijuana,” presentation submitted to the Committee on 6 May 2014. [108] Kevin A. Sabet, Ph.D., “Reefer Sanity: Seven Great Myths About Marijuana,” presentation submitted to the Committee on 6 May 2014. [110] Kevin A. Sabet, Ph.D., “Reefer Sanity: Seven Great Myths About Marijuana,” presentation submitted to the Committee on 6 May 2014. [111] Dr. Perry Kendall, “Cannabis Related Benefits and Harms: Information to Assist in Decision Making about Cannabis Policy,” submitted to the Committee on 21 May 2014. [112] HESA, Evidence, 2nd Session, 41st Parliament, 27 May 2014, 0845 (Dr. Evan Wood, Director of the British Columbia Centre for Excellence in HIV/AIDS, Urban Health Research, as an Individual). [116] Ibid. [117] Ibid., 0910. [118] Ibid. [119] HESA, Evidence, 2nd Session, 41st Parliament, 1 May 2014, 0915 (Robert Ianiro, Director General Controlled Substances and Tobacco Directorate, Healthy Environments and Consumer Safety Branch, Health Canada). [120] HESA, Evidence, 2nd Session, 41st Parliament, 1 May 2014, 0955 (Dr. Meldon Kahan); HESA, Evidence, 2nd Session, 41st Parliament, 8 May 2014, 0850 (Dr. Trevor Theman, President Elect, Federation of Medical Regulatory Authorities of Canada). [122] Umar Syed, President, Canmart, “Submission of Position on Cannabis Policy,” submitted to the Committee 27 May 2014. [123] HESA, Evidence, 2nd Session, 41st Parliament, 1 May 2014, 0955 (Dr. Meldon Kahan); HESA, Evidence, 2nd Session of the 41st Parliament, 8 May 2014, 0850 (Dr. Trevor Theman). [125] HESA, Evidence, 2nd Session of the 41st Parliament, 8 May 2014, 0850 (Dr. Trevor Theman); HESA, Evidence, 2nd Session, 41st Parliament, 13 May 2014, 0915 (Philippe Lucas); HESA, Evidence, 2nd Session, 41st Parliament, 27 May 2014, 1020 (Dr. Didier Jutras-Aswad). [130] Canadian Medical Association, “The Health Risks and Harms Associated with the Use of Marijuana,” submitted to the Committee on 27 May 2014; HESA, Evidence, 2nd Session, 41st Parliament, 1 May 2014, 1000 (Dr. Meldon Kahan). |