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Letters to the Editor
DUTCH GOVERNMENT PRESSURED TO RECONSIDER PLANNED RE-SCHEDULING OF CANNABIS IN DRUG LAW Recently, questions [1] have been asked in the Dutch parliament about the impact of the results of the studies by Peggy van der Pol et al., published in Addiction [2] and Drug and Alcohol Dependence [3]. What was brought forward was the alleged result that Δ-9-tetrahydrocannabinol (THC) strength in marijuana was not a decisive factor in creating cannabis dependence. The Member of Parliament (MP) wanted to know whether this outcome would be a reason for the Dutch government to reconsider the plan to re-schedule marijuana with a content of more than 15% from List 2 (soft drugs, with limited health risks) to List 1 (hard drugs with serious health risks), an act which has received support in parliament, and currently under legal review. The Health Minister recently answered that the outcome was no reason to change the plan, as dependence was only one of the health problems related to heavy cannabis use. He also pointed to the rise in treatment demand in recent years, and suggested that the measure could have a potential deterring effect on crime [2]. The study by van der Pol et al. [3] is exceptional in the number of parameters of cannabis use that have been assessed (and should be praised for the many innovative features). One such parameter is the amount of THC exposure (monthly dose). The study shows a positive association between exposure to THC and dependence. Erroneously, however, in their analysis they control for initial THC exposure, and conclude that upon second follow-up, the association between risk and THC concentration is absent. Without such statistical control, the relationship is even slightly stronger. The absence of THC dose as a risk factor could be interpreted by the public as proof that THC exposure is irrelevant as a health risk. This is strengthened by the suggestion that THC content of the marijuana typically used by the subjects (the issue in the new legal schedule) is compensated by a different smoking pattern, leading to less exposure than would be expected on the basis of THC content alone (titration). The result was, none the less, that a higher THC content did increase the dose of marijuana per joint and, presumably, monthly dose. In an interview with a leading newspaper [4], van der Pol states that when aiming for a reduction in risk for cannabis addiction it would be better to focus on parameters other than THC content, such as money problems and other life events, as reported in van der Pol et al. [5]. With this statement, van der Pol suits the MP’s line of reasoning when questioning the scientific base of the new planned act, which makes a distinction between marijuana with THC content over and below © 2014 Society for the Study of Addiction
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15%. Indeed, the explained variance is low (adjusted R2 = 6%), and THC exposure predicts dependence only marginally. Here too, however, one should be a little more careful. The convenience sample upon which the results are based is highly selective, as was also mentioned by the minister. Only frequent smokers of marijuana in coffee shops were included, and little background information was collected. Variation in exposure in such a sample is naturally restricted, which may affect the assessment of an association with the outcome. To ascertain whether the content of THC or exposure to THC is an important factor, we need a comparison with other less frequent, less heavy users. In this case, the average exposure was a monthly 2 g of THC, with a strong positively skewed distribution (standard deviation was 2.7 g; maximum was 14.5 g). No data from other (Dutch) samples are known to me, and we cannot be sure that bringing down THC content in marijuana will have no impact on cannabis dependence. Conversely, the scientific (health) arguments in favour of a legal distinction between marijuana over and below 15% are not very convincing either. Declaration of interests None. Keywords Cannabis, cannabis potency, dependence risk, drug policy, legal drug schedules, methodology. PAUL LEMMENS
Department of Health Education and Promotion, University of Maastricht, Maastricht, the Netherlands. E-mail: [email protected] References 1. Tweede Kamer der Staten-Generaal. Vergaderjaar 2013– 2014. No 2014Z06079 Vragen van het lid Rebel (PvdA) aan de Staatssecretaris van Volksgezondheid, Welzijn en Sport over het bericht dat de rol van THC in beperkte mate een rol speelt bij cannabisverslaving (ingezonden 3 April 2014) [Dutch House of Commons. Parliamentary year 2013-2014. Questions by the MP Rebel (Labour Party) to the Minister of Health, Social Well-being and Sports, about the message that the role of THC plays a limited role in cannabis dependence . . .]. 2. Rijn M. J. Antwoorden op kamervragen van het Kamerlid Rebel (PvdA) Rebel. [Answers to Parliamentary questions of MP Rebel (Labour Party)] Reference: 358847-119521-VGP. 7 May 2014. 3. van der Pol P., Liebregts N., Brunt T., van Amsterdam J., de Graaf R., Korf D. J. et al. Cross-sectional and prospective relation of cannabis potency, dosing and smoking behaviour with cannabis dependence: an ecological study. Addiction 2014; 109: 1111–9. 4. Brouwers L. Armoede is erger dan zware wiet [Poverty worse than potent marijuana]. Interview. NRC Handelsblad, 18 April 2014. Addiction, 109, 1760–1762
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Letters to the Editor
5. van der Pol P., Liebregts N., Brunt T., van Amsterdam J., de Graaf R., Korf D. J. et al. Predicting the transition from frequent cannabis use to cannabis dependence: a threeyear prospective study. Drug Alcohol Depend 2013; 133: 352–9.
NO GROUNDS TO BEWARE DRINKAWARE We read with interest the article presented for debate Be aware of Drinkaware (24 July 2013), and write to support the need for robust debate about the role of the Drinkaware Trust, but also, crucially, to refute and clarify inaccuracies in the content of the article. The Drinkaware Trust was established in 2006 through a Memorandum of Understanding, drafted with the help of the public health community and signed by the Portman Group, Department of Health, Home Office and devolved administrations. An addendum was then added in 2009 to confirm the core purpose of the Trust as the ‘primary non-governmental vehicle for providing alcohol information and public education’, and was supported by many players in the alcohol industry. These companies replaced the Portman Group, which was not a signatory to the addendum. The Memorandum states clearly: ‘The Trust will contribute to the process of public policy development across the UK via the provision of relevant evidence and insights from the outcomes and evaluations of its supported projects, but otherwise not have a policy function’. Drinkaware’s submissions to the Health Select Committee, referenced in the article, are consistent with this remit. Furthermore, we seek to fulfil our given remit through the provision of objective, independent, comprehensive and evidence-based information about alcohol and by increasing access to this information though consumer campaigns. Our activities are overseen by an independent Medical Advisory Panel chaired by Professor Paul Wallace; other members include Dr Sarah Jarvis, Professor Jonathan Chick, Professor Chris Day and Professor Graham Ogden. All our communications are comprehensively reviewed to ensure that they represent the most recent and robust evidence. Our website, which attracted more than 5 million visitors in 2013, has been granted certification from the Information Standard. The 2009 Addendum to the Memorandum of Understanding made a commitment to review the effectiveness of the Trust in meeting its objectives in 2012. This exercise was conducted by independent auditors who, in addition to contractual work with alcohol companies as stated in the article, have a diverse client base, including Public Health England (Change 4 Life) and the Smokefree Campaign. The auditors were appointed by an Independent © 2014 Society for the Study of Addiction
Review Panel chaired by Sir Hugh Taylor, Chairman of the Guy’s and St Thomas’ NHS Foundation Trust and former Permanent Secretary at the Department of Health. Other Panel members, which the article failed to include, were Professor Sir Ian Gilmore of the Alcohol Health Alliance, Chris Heffer, then Deputy Director, drugs and alcohol, Department of Health and Ben Paige of Ipsos MORI. The audit found no evidence that, as the article suggests, the Trust is ‘an industry vehicle to subvert evidence-based public health policy’. As an organization which is currently funded primarily by voluntary donations from the alcohol industry, we are aware of the concerns in some quarters about potential industry influence. We have therefore recently significantly reshaped the governance structure of the Trust, removing the earlier requirement for quotas of trustees from the alcohol industry and non-industry alcoholrelated background, so that Trustees are now selected entirely on the basis of their knowledge, skills and experience. We recognize that over the years there have been occasions where our information and campaigns have not matched the standards to which we aspire. These instances were the by-product of an organization in development, but one that is constantly learning and improving as it matures in an environment where change can take generations to become sustained. For example, the web copy on alcohol minimum predated the creation of our Medical Advisory Panel, and was clearly inappropriate. Alcohol-related harm is best addressed through a range of efforts, and we acknowledge the World Health Organization position that consumption is most effectively influenced through price, availability and advertising. Public education also has an important role to play in challenging attitudes and behaviour, and Drinkaware’s educational activities are designed to complement the efforts of other organizations in reducing alcohol-related harm. We operate in an evidence-based, open and transparent fashion, and refute the assertion that there are grounds to ‘Be aware of Drinkaware’. Declaration of interests None. Keywords Alcohol education, charity, Drinkaware, independence, industry, policy, public health, responsibility deal. DEREK LEWIS
Chair, The Drinkaware Trust, on behalf of the Board of the Drinkaware Trust, Samuel House, 6 St Albans Street, London SW1Y 4SQ, UK. E-mail: [email protected] Addiction, 109, 1760–1762
Letters to the Editor
DUTCH GOVERNMENT PRESSURED TO RECONSIDER PLANNED RE-SCHEDULING OF CANNABIS IN DRUG LAW Recently, questions [1] have been asked in the Dutch parliament about the impact of the results of the studies by Peggy van der Pol et al., published in Addiction [2] and Drug and Alcohol Dependence [3]. What was brought forward was the alleged result that Δ-9-tetrahydrocannabinol (THC) strength in marijuana was not a decisive factor in creating cannabis dependence. The Member of Parliament (MP) wanted to know whether this outcome would be a reason for the Dutch government to reconsider the plan to re-schedule marijuana with a content of more than 15% from List 2 (soft drugs, with limited health risks) to List 1 (hard drugs with serious health risks), an act which has received support in parliament, and currently under legal review. The Health Minister recently answered that the outcome was no reason to change the plan, as dependence was only one of the health problems related to heavy cannabis use. He also pointed to the rise in treatment demand in recent years, and suggested that the measure could have a potential deterring effect on crime [2]. The study by van der Pol et al. [3] is exceptional in the number of parameters of cannabis use that have been assessed (and should be praised for the many innovative features). One such parameter is the amount of THC exposure (monthly dose). The study shows a positive association between exposure to THC and dependence. Erroneously, however, in their analysis they control for initial THC exposure, and conclude that upon second follow-up, the association between risk and THC concentration is absent. Without such statistical control, the relationship is even slightly stronger. The absence of THC dose as a risk factor could be interpreted by the public as proof that THC exposure is irrelevant as a health risk. This is strengthened by the suggestion that THC content of the marijuana typically used by the subjects (the issue in the new legal schedule) is compensated by a different smoking pattern, leading to less exposure than would be expected on the basis of THC content alone (titration). The result was, none the less, that a higher THC content did increase the dose of marijuana per joint and, presumably, monthly dose. In an interview with a leading newspaper [4], van der Pol states that when aiming for a reduction in risk for cannabis addiction it would be better to focus on parameters other than THC content, such as money problems and other life events, as reported in van der Pol et al. [5]. With this statement, van der Pol suits the MP’s line of reasoning when questioning the scientific base of the new planned act, which makes a distinction between marijuana with THC content over and below © 2014 Society for the Study of Addiction
1761
15%. Indeed, the explained variance is low (adjusted R2 = 6%), and THC exposure predicts dependence only marginally. Here too, however, one should be a little more careful. The convenience sample upon which the results are based is highly selective, as was also mentioned by the minister. Only frequent smokers of marijuana in coffee shops were included, and little background information was collected. Variation in exposure in such a sample is naturally restricted, which may affect the assessment of an association with the outcome. To ascertain whether the content of THC or exposure to THC is an important factor, we need a comparison with other less frequent, less heavy users. In this case, the average exposure was a monthly 2 g of THC, with a strong positively skewed distribution (standard deviation was 2.7 g; maximum was 14.5 g). No data from other (Dutch) samples are known to me, and we cannot be sure that bringing down THC content in marijuana will have no impact on cannabis dependence. Conversely, the scientific (health) arguments in favour of a legal distinction between marijuana over and below 15% are not very convincing either. Declaration of interests None. Keywords Cannabis, cannabis potency, dependence risk, drug policy, legal drug schedules, methodology. PAUL LEMMENS
Department of Health Education and Promotion, University of Maastricht, Maastricht, the Netherlands. E-mail: [email protected] References 1. Tweede Kamer der Staten-Generaal. Vergaderjaar 2013– 2014. No 2014Z06079 Vragen van het lid Rebel (PvdA) aan de Staatssecretaris van Volksgezondheid, Welzijn en Sport over het bericht dat de rol van THC in beperkte mate een rol speelt bij cannabisverslaving (ingezonden 3 April 2014) [Dutch House of Commons. Parliamentary year 2013-2014. Questions by the MP Rebel (Labour Party) to the Minister of Health, Social Well-being and Sports, about the message that the role of THC plays a limited role in cannabis dependence . . .]. 2. Rijn M. J. Antwoorden op kamervragen van het Kamerlid Rebel (PvdA) Rebel. [Answers to Parliamentary questions of MP Rebel (Labour Party)] Reference: 358847-119521-VGP. 7 May 2014. 3. van der Pol P., Liebregts N., Brunt T., van Amsterdam J., de Graaf R., Korf D. J. et al. Cross-sectional and prospective relation of cannabis potency, dosing and smoking behaviour with cannabis dependence: an ecological study. Addiction 2014; 109: 1111–9. 4. Brouwers L. Armoede is erger dan zware wiet [Poverty worse than potent marijuana]. Interview. NRC Handelsblad, 18 April 2014. Addiction, 109, 1760–1762
1762
Letters to the Editor
5. van der Pol P., Liebregts N., Brunt T., van Amsterdam J., de Graaf R., Korf D. J. et al. Predicting the transition from frequent cannabis use to cannabis dependence: a threeyear prospective study. Drug Alcohol Depend 2013; 133: 352–9.
NO GROUNDS TO BEWARE DRINKAWARE We read with interest the article presented for debate Be aware of Drinkaware (24 July 2013), and write to support the need for robust debate about the role of the Drinkaware Trust, but also, crucially, to refute and clarify inaccuracies in the content of the article. The Drinkaware Trust was established in 2006 through a Memorandum of Understanding, drafted with the help of the public health community and signed by the Portman Group, Department of Health, Home Office and devolved administrations. An addendum was then added in 2009 to confirm the core purpose of the Trust as the ‘primary non-governmental vehicle for providing alcohol information and public education’, and was supported by many players in the alcohol industry. These companies replaced the Portman Group, which was not a signatory to the addendum. The Memorandum states clearly: ‘The Trust will contribute to the process of public policy development across the UK via the provision of relevant evidence and insights from the outcomes and evaluations of its supported projects, but otherwise not have a policy function’. Drinkaware’s submissions to the Health Select Committee, referenced in the article, are consistent with this remit. Furthermore, we seek to fulfil our given remit through the provision of objective, independent, comprehensive and evidence-based information about alcohol and by increasing access to this information though consumer campaigns. Our activities are overseen by an independent Medical Advisory Panel chaired by Professor Paul Wallace; other members include Dr Sarah Jarvis, Professor Jonathan Chick, Professor Chris Day and Professor Graham Ogden. All our communications are comprehensively reviewed to ensure that they represent the most recent and robust evidence. Our website, which attracted more than 5 million visitors in 2013, has been granted certification from the Information Standard. The 2009 Addendum to the Memorandum of Understanding made a commitment to review the effectiveness of the Trust in meeting its objectives in 2012. This exercise was conducted by independent auditors who, in addition to contractual work with alcohol companies as stated in the article, have a diverse client base, including Public Health England (Change 4 Life) and the Smokefree Campaign. The auditors were appointed by an Independent © 2014 Society for the Study of Addiction
Review Panel chaired by Sir Hugh Taylor, Chairman of the Guy’s and St Thomas’ NHS Foundation Trust and former Permanent Secretary at the Department of Health. Other Panel members, which the article failed to include, were Professor Sir Ian Gilmore of the Alcohol Health Alliance, Chris Heffer, then Deputy Director, drugs and alcohol, Department of Health and Ben Paige of Ipsos MORI. The audit found no evidence that, as the article suggests, the Trust is ‘an industry vehicle to subvert evidence-based public health policy’. As an organization which is currently funded primarily by voluntary donations from the alcohol industry, we are aware of the concerns in some quarters about potential industry influence. We have therefore recently significantly reshaped the governance structure of the Trust, removing the earlier requirement for quotas of trustees from the alcohol industry and non-industry alcoholrelated background, so that Trustees are now selected entirely on the basis of their knowledge, skills and experience. We recognize that over the years there have been occasions where our information and campaigns have not matched the standards to which we aspire. These instances were the by-product of an organization in development, but one that is constantly learning and improving as it matures in an environment where change can take generations to become sustained. For example, the web copy on alcohol minimum predated the creation of our Medical Advisory Panel, and was clearly inappropriate. Alcohol-related harm is best addressed through a range of efforts, and we acknowledge the World Health Organization position that consumption is most effectively influenced through price, availability and advertising. Public education also has an important role to play in challenging attitudes and behaviour, and Drinkaware’s educational activities are designed to complement the efforts of other organizations in reducing alcohol-related harm. We operate in an evidence-based, open and transparent fashion, and refute the assertion that there are grounds to ‘Be aware of Drinkaware’. Declaration of interests None. Keywords Alcohol education, charity, Drinkaware, independence, industry, policy, public health, responsibility deal. DEREK LEWIS
Chair, The Drinkaware Trust, on behalf of the Board of the Drinkaware Trust, Samuel House, 6 St Albans Street, London SW1Y 4SQ, UK. E-mail: [email protected] Addiction, 109, 1760–1762
