http://www.clerk.parliament.govt.nz/Content/SelectCommitteeReports/i6c.pdf INQUIRY INTO HEALTH STRATEGIES AND LEGAL OPTIONS FOR CANNABIS I.6C has (on pages 15-21 of 80): -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Sect.5 Findings on cannabis-related harm Cannabis dependency Overseas data indicates that an estimated 10 percent of regular cannabis users develop substance dependence disorder, a recognised mental illness. The current understanding is that the dependence is a psychological dependency rather than a physical addiction. In New Zealand, a 1999 Ministry of Health estimate is that nearly 20 percent of the population will suffer an alcohol use disorder, around 6 percent will meet the clinical criteria for drug abuse or drug dependence, and some 2 to 3 percent of the population are at serious risk of a cannabis dependence disorder. In 1996, the Ministry of Health reported that cannabis dependence is more likely to occur among users who are also dependent on alcohol. The Christchurch Health and Development Study (CHDS)—a 21-year longitudinal study of the health, development, and adjustment of a birth cohort of 1,265 children born in urban Christchurch during mid-1977—draws a picture of cannabis as a social drug with common usage among young people. The study emphasises that for the majority of occasional recreational cannabis users there is no evidence to suggest that usage has harmful effects. In summation, the authors state that ‘cannabis use is likely to be no more harmful than alcohol use and may very well be shown to be less harmful than alcohol use.’ However, for a minority of regular and heavy users, there is evidence of potential harmful effects. The study identified that one in every 10 young people in the cohort had developed symptoms consistent with cannabis dependence, although it is not clear whether this is indicative of long-term harm. Both the CHDS and the Dunedin Multidisciplinary Health and Development Study indicate that by the age of 21 more than 9 percent of cohort members met criteria for cannabis dependence.{note 7} These were the groups that also reported cannabis use by age 15. One study (Hall, 1994) estimates that about 9 percent of all cannabis users and about 33 to 50 percent of daily users meet the criteria for dependence at some point. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Note 7: Nine hundred and forty-three young adults from a birth cohort of 1,037 subjects born in Dunedin in 1972–73 were studied at age 21. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Effects of cannabis use Effects of cannabis use can include relaxation, mood elevation, a sense of tranquillity, hilarity, and mood swings. Lethal overdose is almost impossible. However, harmful acute and chronic effects of cannabis use are associated with frequent and heavier use. Potential acute effects can include not only cognitive and psychomotor impairment leading to increased risk of injury, loss of short-term memory, and interference with learning, but also brief periods of psychosis. Potential chronic effects can include harm to the central nervous system (neurotoxicity, impaired cognitive functioning and cognitive decline), possible psychosis and exacerbation of schizophrenia in vulnerable individuals, cannabis dependence, and damage to the respiratory, immune and cardiovascular systems. The behavioural effects caused by the active ingredient THC are complex and vary between individuals. They can include sedation, weakness, fatigue, euphoria, a rapid flow of thoughts, feelings of tranquillity, dizziness, dry mouth, appetite stimulation, impairment of perception and memory, analgesia, tachycardia, and a reduction in nausea, vomiting, and intraocular pressure. The Royal College of Australian and New Zealand Psychiatrists cited research that suggests heavy (at least daily) and chronic (more than 10 years) use of cannabis is associated with anxiety, paranoia, depression, and associated adverse motivational and societal issues. High risk groups Youth, particularly M a ori youth, have been consistently identified in a number of reports in the past decade as a high-risk group with regard to cannabis abuse and cannabis-related harm. Numerous reports and studies indicate a significant level of adolescent use, and identify problems associated with frequent cannabis use by adolescents. Although frequent cannabis use by adolescents may be symptomatic of broader and more complex social issues, it has been linked in much of the literature to truancy and poor performance, impairment in school and behavioural functioning, and a pattern of multiple substance abuse from adolescence to young adulthood. People with co-existing drug use and other mental disorders, polydrug users, and pregnant women have also been identified as being at greater risk of drug-related harm. Expert submitters’ views of cannabis-related harm While the expert submissions viewed the cannabis issue from different areas of expertise, one theme that emerged was that the risk of cannabis-related harm relates to the extent of use and to vulnerability. The effects of using cannabis vary widely between individuals, and depend on a number of factors, including: •frequency of use •method of administration and experience •the amount and potency of the cannabis •the individual’s body weight. The ESR stated that blood THC levels are dose dependent; that is, they depend on how potent the cannabis is and how much is absorbed. However, for the 5 to 10 percent of mainly young New Zealanders who use cannabis heavily, various social, mental, and physical harms can result. Those people tend to come from already socially disadvantaged groups and have pre-existing problems. For the majority of occasional cannabis users, there is a low risk of cannabis-related harm. -=##=- Recommendation 5. We recommend to the Government that it adopt an all-of-Government approach to enhance the quality, and ensure the accuracy, of youth-appropriate health messages. -=##=- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Sect.6 Mental illness The 1998 report on the mental health effects of cannabis by the Health Committee of the 45th Parliament considered the effect of cannabis use on people’s development and the role of cannabis as a trigger for mental illness. That committee observed that the linkages between cannabis use and mental illness were not clearly defined. It noted the view of the Mental Health Research Institute of Victoria that ‘cannabis may contribute to the early onset of psychosis amongst those who are already predisposed to schizophrenia,’ but that scientific evidence had not demonstrated a causal effect; and that permanent brain damage or the development of an amotivational syndrome amongst users was unproven.{note 8} Since that time, more evidence has been produced on the subject of mental illness and cannabis, and the current inquiry prompted a number of submissions expressing concern about the potential health effects of cannabis use, such as depression, schizophrenia, paranoia, suicide, anxiety, and personality disorders. Eighty-five submitters were concerned about these adverse mental health effects, and identified children, youth, individuals with a mental health illness or susceptibility to a mental health disorder, and pregnant women as being particularly adversely affected. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Note 8: Inquiry into the Mental Health Effects of Cannabis, Report of the Health Committee, 1998, AJHR, I.6A, p. 43. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Psychosis The Royal College of Australian and New Zealand Psychiatrists recognises that cannabis psychosis is a contentious issue, and is difficult to prove. While extant research does not appear to substantiate a link between cannabis use and psychosis, the college notes that there are reports of distinct psychosis occurring in heavy cannabis users, commonly paranoid ideation and marked aggression. The psychosis is always brief, however, and there is no evidence that a chronic psychosis is induced by cannabis. The New Zealand Medical Association stated that in susceptible individuals, excessive cannabis use can cause psychosis and other mental illness. Schizophrenia The Royal College of Australian and New Zealand Psychiatrists noted that there is no convincing evidence that cannabis use causes schizophrenia. There appears to be only limited evidence that leads to the hypothesis that cannabis abuse and dependence may increase the risk of schizophrenia. The college notes that the possibility that cannabis is an independent cause of schizophrenia cannot be disproven, but the absence of an increased incidence of schizophrenia over the past 30 years, during which time cannabis use has become much more prevalent, is strongly against such a possibility. However, people with pre-existing psychiatric disorders such as schizophrenia are especially vulnerable to the adverse health effects of cannabis use because cannabis generally provokes relapse and aggravates existing symptoms. Cognitive changes The Royal College of Australian and New Zealand Psychiatrists noted there is no evidence that there is irreversible brain damage from cannabis use. Long-term use does raise concerns about cognitive changes, especially when the use has been heavy and prolonged. However, research into residual cognitive changes after cessation of cannabis use has found only minor deficits or no difference between users and non-users. Suicide The Royal College of Australian and New Zealand Psychiatrists noted that studies into the relationship between cannabis use and suicide have not established a clear linkage independent of background social variables and the presence of mental illness. However, acute suicidal feelings, and possibly actions, in susceptible persons may be associated with amine depletion in cannabis users after cannabis ingestion. The findings of the 21-year CHDS suggest that there are significant associations between cannabis use—particularly regular cannabis use—and juvenile delinquency, depression, and suicidal behaviours among the cohort members. The study notes that ‘As a general rule, young people reporting at least weekly use of cannabis emerged as being at increased risks of these outcomes.’ {note 9} The ESR has conducted some toxicological analysis into youth suicide and cannabis use, but the results are inconclusive. Only about one third of all youth suicides each year are received at ESR for toxicological testing, and ESR analyses for cannabis only if requested to do so by the police. In the case of carbon monoxide poisoning—one of the more prevalent methods of youth suicide—ESR is rarely asked to analyse for anything other than carbon monoxide. For mid-1997 to mid-1998, 21 of the 46 cases of youth suicide in the 15 to 24-year age group referred to ESR were for carbon monoxide poisoning. The remaining 25 were screened for a range of drugs including cannabis, and 14 (30.4 percent of all cases referred to ESR, or 56 percent of all cases screened for drugs) tested positive for cannabis. As those results were from people tested because drug use was suspected, we would expect to find high levels of positive results. This does not indicate any relationship between cannabis and suicide. We recognise the limits on the available data, but we are concerned that the ESR detected traces of cannabis in 14 out of 25 cases screened. We are concerned that the role of cannabis in youth suicide cases may be greater than currently known, and we note the recent coronial findings on this matter. We believe that further investigation is required to establish a more accurate picture of the role of cannabis in all suicides. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Note 9: CHDS submission (A), p. 18. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -=##=- Recommendation 6. We recommend to the Government that it require the ESR to test all suicide referrals for traces of all illegal drugs and alcohol, including cannabinoids, in order to further investigate the extent of the relationship between cannabis use and suicide in New Zealand. -=##=- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Sect.7 Behavioural effects Sixty-seven submitters had concerns related to adverse behavioural effects of cannabis use. Behaviours most frequently stated as having adverse health effects, particularly on young people, included amotivational syndrome, extreme lack of interest, social dislocation, loss of friends, deterioration in schoolwork, and lack of educational achievement. However, Professor Paul Smith of the School of Medical Sciences (Department of Pharmacology and Toxicology) at the University of Otago stated that there is no definite causal link established between cannabis use and amotivational syndrome. In their 1998 submission to the Health Committee of the 45th Parliament, the police noted that although conduct disorders such as truancy, persistent lying, and non-confrontational stealing were associated with adolescent cannabis use, they believed cannabis use was not the cause of these behaviours. Evidence suggests that cannabis use does not cause behavioural difficulties; instead, it is frequently used by youth who are predisposed to deviant behaviours.{note 10} Many submitters to this inquiry commented that people are less aggressive, more thoughtful, and calmer under the influence of cannabis. Some submitters talked about being very aggressive and abusive until they gave up alcohol for cannabis. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Note 10: Inquiry into the Mental Health Effects of Cannabis, Report of the Health Committee, 1998, AJHR, I.6A, p. 15. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Violence There is, and has been for a considerable period of time, a debate over whether cannabis use produces violence. The debate appears to date back to at least 1926, when a New Orleans newspaper exposed the ‘menace of marijuana’, claiming an association between the drug and crime, especially violent crime. We understand that most currently available research demonstrates that this relationship does not exist, and that human violent behaviour is either decreased or unchanged with cannabis administration. The animal literature suggests the same relationship: cannabis tends to foster submissive behaviours and suppress attack and threat behaviours. Some animal studies have noted heightened aggression with cannabis administration, but there is usually a third variable such as sleep deprivation, social seclusion, or pre-treatment with another drug that might account for this result. In contrast, crime studies repeatedly demonstrate the high and significant involvement of alcohol in general violent behaviour. Respiratory problems Sixty-seven submitters stated that cannabis causes physically harmful effects to users. The risk of cancer of the respiratory system and respiratory disease were the most frequently mentioned adverse physical effects related to the most common means of consumption— smoking. Lung damage One of the major health problems relating to cannabis is that the majority of users ingest it by smoking cannabis cigarettes either consisting of cannabis alone or in combination with tobacco. Professor Smith observed that pure cannabis cigarettes can induce bronchial tumours when smoked, as a result of carcinogens generated as the cannabis burns. This means that smoking cannabis carries a similar risk of lung cancer and other cancers as tobacco. However, it must also be recognised that, with the exception of extremely heavy users, cannabis users tend to smoke less than tobacco smokers. The Thoracic Society of Australia and New Zealand and the Asthma and Respiratory Foundation of New Zealand in a joint submission said that the short-term health effects of smoking cannabis are identical to those of tobacco smoke: airway inflammation is provoked, and symptoms of acute bronchitis occur. These two bodies, along with the New Zealand Medical Association, stated that the long-term smoking of cannabis can cause lung damage, and that the effect of smoking cannabis is likely to be just as harmful as tobacco smoking. Resultant harm includes the development of chronic bronchitis and emphysema, and possibly lung cancer. However, adequate data to validate this statement will not be available for another 25 to 30 years, given the very slow rate at which these diseases progress. The Dunedin Multidisciplinary Health and Development Study lends some support to this statement, but it also identifies the need for carefully designed case control studies. The study states that respiratory symptoms in study members who met strict criteria for cannabis dependence, after controlling for the effects of tobacco, were comparable to the effects from smoking one to 10 cigarettes daily. One overseas study (Tzu-Chin et al, 1988) that compared the pulmonary hazards of smoking cannabis and tobacco concluded that smoking cannabis, regardless of THC content, results in a substantially greater respiratory burden of carbon monoxide and tar than smoking a similar quantity of tobacco. This 1988 study was based on an all-male cohort of 15 habitual smokers of cannabis and tobacco, and found that smoking a joint of cannabis results in a fivefold increase in carbon monoxide levels in the blood, and a threefold increase in the amount of tar substances which are inhaled. We have serious concerns about the potential long-term pulmonary consequences of habitual smoking of cannabis cigarettes. Although we recognise that comparisons of cannabis and tobacco-related harm to the respiratory tract and lungs may lead to exaggerations of the degree of danger resulting from cannabis use, there is still widespread debate about the harmfulness of cannabis compared to tobacco. Given the risks associated with inhaling burnt plant matter, we recognise that the use of high-THC cannabis may have the effect of decreasing harm by reducing the amount of smoke inhaled by the user. We further note that the current practice in New Zealand of users holding smoke in to maximise the effect of the THC has been shown to increase risk of lung damage without increasing the high. We encourage the provision of harm reduction information that makes this clear. Some submitters commented on the use of devices that steam cannabis and vapourise cannabinoids as an alternative to smoking the dried plant. GW Pharmaceuticals, the company developing cannabis-based products for commercial release in the United Kingdom, submitted that smoking is not an acceptable delivery system for a medicine. This submission identified vaporisers, nebulisers, or dry powder inhalers as potential delivery systems for medicinal use. In our report on the Smoke-free Environments (Enhanced Protection) Amendment Bill, we recommended widening the definition of ‘to smoke’ to ensure non-tobacco products were covered by the Smoke-free Environments Act 1990. This change recognised that smoke from non-tobacco products is also a public health risk. We consider further information should be made available to the public about the risks of lung damage from smoking cannabis, as is currently done for tobacco. -=##=- Recommendation 7. We recommend to the Government that it ensure provision of harm reduction information designed to minimise lung damage resulting from the smoking of cannabis. -=##=-