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It is currently illegal to cultivate, possess, supply and use cannabis through the Misuse of Drugs Act 1975.1 However, the Minister of Health is able to approve the medical use of the cannabis plant, although in practice, the decision has been delegated to the Associate Health Minister Hon Peter Dunne.2 In 2015, the first application was approved for the use of cannabis oil for a case of status epilepticus.2 In the context of this application, Hon Peter Dunne said that this should not be seen as a significant change in policy.2In 2010, consent was given for use of the cannabis medicine, Sativex, in New Zealand.3 This medicine is an extract of the cannabis plant and is a standardised product with known levels of psychoactive content unlike illicit cannabis, which can vary greatly in potency.4 Sativex is available on application to the Ministry of Health by the patient, the patient s GP and specialist.4 Sativex is not fully funded by PHARMAC, and is relatively expensive compared to illicit cannabis.3 As of January 27 2016, 104 applications to prescribe Sativex had been approved in New Zealand.5 In the same month, a patient who had recurring seizures that her specialist said could lead to coma and death had the medicine fully funded.6As cannabis use is illegal, it is difficult to get information about who is using cannabis medicinally and for what reasons. In 2003, the Green Party of New Zealand randomly surveyed general practitioners and selected hospital specialists about their views on medicinal cannabis.7 The results showed that 20% of these doctors knew they had patients who were using cannabis medicinally. They also showed that 32% of doctors would consider prescribing medicinal cannabis products if they were legally allowed and 10% of doctors had patients they felt could benefit from cannabis.In 2006, the Green Party of New Zealand introduced the Misuse of Drugs (Medicinal Cannabis) Amendment Bill, but it was defeated in a conscience vote in 2009.8 However, other countries have legalised medicinal cannabis use, eg, Israel in 1996,9 Canada in 2001,10 and The Netherlands in 2003.11 In the US, medicinal cannabis use is illegal at the Federal level, but medicinal use of cannabis is currently legal in 23 states.12 In Canada and The Netherlands, the government supplies cannabis to users directly or through registered suppliers, allowing them to control quality and supply, whereas in the US, medical cannabis users have to grow or find their own supply, leading to a free market in cannabis.10,11,13 In California, where medicinal cannabis was legalised in 1996 through a citizen s initiative, any debilitating condition can be treated with cannabis if a physician recommends it.12 This has led to recreational users being able to access medicinal cannabis through misleading their doctor about their health, or with their doctor s cooperation.13Given the defeat of the Green Party s bill, legalisation of medicinal cannabis is unlikely to happen in New Zealand in the foreseeable future. This leaves practitioners with little information about who uses cannabis medicinally, and why. The aim of this study was to explore the characteristics of medicinal cannabis users using representative national survey data.MethodsConfidentialised, unit record data from the 2012/2013 New Zealand Health Survey were supplied by the Ministry of Health (MoH) with administration through Statistics New Zealand.14 The adult data set contains 13,009 respondents, aged 15 years and above, who were living in a private or non-private dwellings, and were from the New Zealand usually resident population. Non-private dwellings include such things as aged care accommodation and student hostels. However, people in hospitals, prisons, dementia units or those in hospital-level care accommodation were excluded, as well as people in meshblocks with sparse populations, and New Zealand s off-shore islands.The survey used a complex method of sampling that included the means of oversampling Mori, Asian and Pacific people, but the survey has been weighted to produce a representative sample. Estimates produced by these weights form unbiased estimates of population values. The data set also includes a set of 100 replicate weights which create 100 further estimates. The variance of these estimates around the unbiased estimate gives the sampling variance. For the purpose of this paper, SUDAAN was used to do these calculations.15Results can suffer from bias when the number of respondents that contribute to an estimate are too few, or an estimate may have little meaning if it has large sampling variation. The relative sampling error (RSE) is monitored to check if an estimate has these problems. The MoH advises that estimates with a RSE of 30%-50% should be used with caution, and estimates with RSE over 50% should be considered too unreliable for most practical purposes.14 In this article, estimates with RSE between 30% and 50% are marked with an asterisk, estimates over 50% are marked with a double asterisk, and estimates that rely on few respondents will be supressed, eg, an estimate of 6.4% with a RSE of 45% will be marked as 6.4*%.The New Zealand Health Surveys consist of a core questionnaire and rotating modules. In the core questionnaire, survey respondents were asked if they had used cannabis in the last 12 months for recreational or non-medical purposes, or to get high. In the 2012/13 survey, the tobacco, alcohol and drug use modules were also included, which asked questions about use of those products. Questions used from this module include: lifetime use of cannabis; cannabis use in the last 12 months; and whether cannabis was used in the last 12 months to intentionally treat a range of medical conditions pain, nausea, depression, anxiety/nerves, other, or none of these. These questions were used to assign people to a category of cannabis use: non-users respondents who had never used cannabis; ex-users respondents who had used cannabis but had not done so in the last year; last year users: non-medicinal respondents who had used cannabis in the last year, but who had not intentionally used it to treat a medical condition; last year users: medicinal respondents who had used cannabis in the last year, and had intentionally used it to treat a medical condition. Not all respondents could be assigned to a category, either because they had answered don t know, or refused to answer a particular question, or because their answer to the question from the core module disagreed with their answer to the questions in the drug use module. Whenever an assignment could not be made directly from the data, the following rules were used to make a classification, and they were done in this order: a) only use information from drug use module questions; b) use additional information from main module question if data is missing from drug module questions; c) any unresolved classification has data for the missing question to be treated as if they answered No. The classifications are outlined in Table 1. Table 2 shows the number of people classified into each group according to these rules.Table 1: Questions and answers used to classify cannabis users. Notes: 1 - All identical classifications are similarly coloured. 2- Non-italicised, bolded classifications are classifications where data is consistent and not missing; italicised classifications are either contradictory or have missing data. The following rules were used to define an italicised classification in this order: a) use information from drug module questions only; b) use additional information from main module question if data is missing from drug module questions; and c) any unresolved classification has data for the missing question to be treated as if they answered \"No\". Table 2: Count of Classifications by the rules applied. Non-Users Ex-Users Last Year Use non-Medicinal Last Year Use Medicinal Total Cumulative % classified No Rule 7,379 3,924 587 648 12,538 96.4 Rule a 42 129 153 0 324 98.9 Rule b 0 15 12 6 33 99.1 Rule c 94 3 17 0 114 100.0 Total 7,515 4,071 769 654 13,009 While people who answered don t know may be ambiguous as to their classification (eg, they could not remember if they had used cannabis 11 or 13 months ago, or didn t know if a herbal remedy contained cannabis), those people who refused were more likely to be respondents who ought to have answered yes, but were reluctant to do so; for example, they did not want to admit to a criminal offense. However, since respondents could also lie about use, the categories can be described as admitted use rather than actual use, and therefore are an undercount of actual use. The size of the groups get smaller when moving from classification 1 to 4 so that putting a respondent in a category with more respondents, rather than a category with fewer (eg, non-user, rather than ex-user), means they make a lesser contribution to the results.The data were analysed, and proportions, means and their 95% confidence intervals appear in the tables for all four groups, and are commented on in the results section. It is well known that cannabis users and non-cannabis users have different characteristics, however, little is known about the differences between medicinal and non-medicinal users of cannabis, so their responses were modelled, compared, and tested using p-values. If the responses were continuous, they were analysed using regression methods. If the responses were from a question with two or more options, they were analysed using multinomial logistic regression with a generalised logit link. In both cases, as there was only one class variable, the proportions or means presented in the tables were equivalent to the conditional marginal means outputted by these regression analyses. The difference between the conditional marginal means for groups 3 and 4 were tested, and the associated p-value appears in the tables. As age, sex and ethnicity are known to be associated with cannabis use, the models were re-run with these factors as confounders to see if that changed the interpretation of the differences; if so, this is mentioned.ResultsPrevalence in major demographic factorsOverall, 58.7% (57.7-59.8) of respondents were non-users, 30.2% (29.3-31.2) had used cannabis, but had not done so in the last year, while 6.5% (5.9-7.1) had used cannabis in the last year, but not medicinally, and 4.6% (4.1-5.1) had used it medicinally in the last year (see Table 3). Of the people using cannabis medicinally, 68.6% (61.5-75.0) had also used it recreationally, or for non-medicinal purposes, or to get high in the last year.Table 3: Prevalence of cannabis use across major demographic variables. Non-Users ex-Users Last Year Users: non-Medicinal Last Year Users: Medicinal p-value for difference between group 3 and 4 Statisitic 95% CI Statisitic 95% CI Statisitic 95% CI Statisitic 95% CI All 58.7 57.7-59.8 30.2 29.3-31.2 6.5 5.9-7.1 4.6 4.1-5.1 0.0000 Sex (row %) Female 62.3 60.8-63.8 29.8 28.4-31.2 4.5 3.9-5.3 3.3 2.8-3.9 0.0062 Male 54.9 53.4-56.4 30.7 29.2-32.2 8.5 7.6-9.5 5.9 5.2-6.8 0.0001 Age Mean 48.9 48.5-49.2 42.1 41.6-42.6 30.7 29.8-31.7 33.1 31.8-34.4 0.0063 Age Group (row %) 15-24 56.6 53.8-59.4 19.9 17.7-22.2 14.7 12.6-17.0 8.8 7.3-10.6 0.0000 25-34 43.4 40.3-46.5 38.7 35.7-41.7 10.4 8.6-12.6 7.5 6.1-9.2 0.0222 35-44 46.0 42.9-49.1 43.3 40.1-46.5 6.5 5.3-7.9 4.3 3.4-5.3 0.0057 45-54 49.9 47.4-52.5 41.6 39.1-44.2 4.3 3.5-5.2 4.2 3.3-5.4 0.9412 55+ 79.3 77.8-80.6 18.8 17.4-20.2 0.9 0.7-1.3 1.1 0.7-1.6 0.6226 Ethnicity (row %) Mori 36.3 33.6-39.0 39.1 36.6-41.6 14.5 12.5-16.7 10.2 8.7-12.0 0.0016 Pacific people 68.2 63.3-72.7 24.7 20.6-29.4 4.9 * 3.2-7.6 2.2 * 1.3-3.5 0.0257 Asian 91.1 88.5-93.1 6.3 4.8-8.2 - - - - - European/Other 57.0 55.7-58.3 32.8 31.6-34.1 5.8 5.2-6.6 4.4 3.8-5.1 0.0029 Notes: 1 - an estimate with RSE between 30% and 50% will be marked with an asterisk, estimates with RSE over 50% will be marked with a double asterisk and estimates that rely on a few respondents will be suppressed.SexNon-users were more likely to be female than male (54.5% (53.5-55.4) vs 45.5% (44.6-46.5), respectively), ex-users were more evenly split (male 50.8% (48.8-52.4), female 49.4% (47.7-51.2)), and last year users were more likely to be male, whether medicinal users (62.9% (57.9-67.6)) or non-medicinal users (63.9% (59.6-67.9)). Of the people using cannabis for medicinal purposes only, 61.0% (51.7-69.7) were male.AgeNine percent (8.8% (7.3-10.6)) of 15-24-year-olds said they used cannabis for medicinal reasons, and 14.7% (12.6-17.0) had used it non-medicinally. This age group had the largest proportion of both types of users. They were also the group with the second largest proportion of respondents who have never used cannabis (56.6% (53.8-59.4)), behind the oldest age group, 55+ years, with 79.3% (77.8-80.6). The proportion of those who have never used cannabis in the three middle age groups lies between 43% and 49%.Prioritised ethnicityTen percent of Mori reported using cannabis medicinally (10.2% (8.7-12.0)) and 14.5% (12.5-16.7) reported using cannabis non-medicinally. Mori have the highest rates of medicinal and non-medicinal use and also ex-use (39.1% (36.6-41.6)). However, European New Zealanders/Others make up 64.3% (60.2-68.2) of non-medicinal users and 67.9% (62.7-72.6) of medicinal users.Demographic factors associated with medicinal use amongst cannabis usersMedicinal users of cannabis were more likely to have no school qualification (33.7% (29.1-38.7)) compared to non-medicinal users (24.9% (21.5-28.7)), and less likely to have qualifications from Year 13/Form 7 (see Table 4).Table 4: Demographic information about Cannabis users and non-users. Non-Users ex-Users Last Year Users: non-Medicinal Last Year Users: Medicinal p-value for difference between group 3 and 4 Statisitic 95% CI Statisitic 95% CI Statisitic 95% CI Statisitic 95% CI School Qualifications (col %) None 27.1 25.6-28.8 21.3 19.7-23.0 24.9 21.5-28.7 33.7 29.1-38.7 0.0056 Year 11/ Form 5 17.7 16.5-18.9 20.3 18.6-22.0 21.5 17.8-25.8 23.3 18.0-29.6 0.6304 Year 12/ Form 6 16.2 14.9-17.6 23.4 21.5-25.4 21.8 17.9-26.3 21.6 17.2-26.7 0.9473 Year 13/ Form 7 17.0 15.7-18.4 26.0 23.8-28.2 27.4 22.4-33.0 16.0 12.2-20.6 0.0008 Non-NZ qualification 22.0 20.6-23.5 9.1 7.6-10.8 4.4 2.7-6.9 5.4 3.4-8.6 0.5171 New Zealand Deprivation Index 2006 (col %) Deciles 1 & 2 (least deprived) 21.1 20.0-22.3 21.7 20.1-23.5 11.3 * 7.7-16.4 14.2 * 10.0-19.8 0.3088 Deciles 3 & 4 21.5 20.3-22.8 20.3 18.7-22.1 19.6 15.5-24.5 11.7 * 8.2-16.4 0.0028 Deciles 5 & 6 20.1 19.0-21.2 19.9 18.5-21.4 23.5 18.7-29.1 20.8 15.5-27.4 0.5215 Deciles 7 & 8 19.9 19.0-20.8 19.9 18.8-21.0 21.8 18.3-25.7 21.2 16.9-26.2 0.8464 Deciles 9 & 10 (most deprived) 17.4 16.5-18.3 18.2 16.9-19.5 23.7 20.3-27.5 32.1 27.5-37.0 0.0025 Household No of adults (mean) 2.5 2.5-2.6 2.4 2.4-2.5 2.9 2.8-3.1 2.7 2.6-2.8 0.0022 No of children (mean) 0.6 0.5-0.6 0.8 0.8-0.8 0.8 0.7-0.9 0.7 0.6-0.8 0.1665 Income Source (%) Income from employer1 52.3 50.9-53.8 69.2 67.0-71.3 70.4 66.2-74.3 65.0 59.9-69.8 0.0899 Invalids/sickness/ accident benefits2 3.5 3.1-4.0 5.3 4.5-6.2 7.0 4.8-10.0 16.8 13.6-20.5 0.0000 Self-employment3 11.1 9.9-12.3 18.5 16.8-20.3 10.6 * 7.7-14.4 9.8 7.2-13.2 0.7488 Unemployment benefit 1.2 0.9-1.6 1.7 1.3-2.1 7.1 5.3-9.5 9.3 * 6.5-13.0 0.2491 Domestic purposes benefit 1.5 1.2-1.8 4.6 3.9-5.3 4.3 3.3-5.8 7.5 5.9-9.4 0.0041 Student allowance 2.5 2.0-3.1 3.0 2.3-4.0 9.2 * 6.2-13.6 6.5 * 4.3-9.5 0.1976 Interest/dividends/ rents/other investments 14.2 12.5-16.1 14.2 12.2-16.4 8.1 * 5.6-11.6 2.9 ** 1.5-5.6 0.0063 Retirement age benefits4 25.8 25.0-26.6 5.3 4

Summary

Abstract

Aim

To explore the characteristics of medicinal and non-medicinal cannabis users, and the conditions that were treated with cannabis.

Method

The data comes from the New Zealand Health Survey 2012/2013, which sampled 13,009 people, aged 15+ years, living in private or non-private dwellings in New Zealand. Participants self-reported cannabis use and were put into groups: 1) non-users; 2) ex-users; 3) last year users non-medicinal; 4) last-year users medicinal. Prevalence was reported for the major demographic subgroups; sex, age and ethnicity. Regression models were then used to find associations between demographic characteristics and cannabis use for groups 3 and 4.

Results

About five percent (4.6%, 95% CI 4.1-5.1) of those aged 15+ report using cannabis medicinally. This use was associated with being male, younger, less well-educated and relatively poor. While Mori have the highest prevalence of medicinal use, European NZ/Others make up 67.9% (95% CI 62.7-72.6) of medicinal users. Reported medicinal use was associated with reported conditions that were typically hard to manage: pain, anxiety/nerves and depression. Medicinal users were more likely to report chronic pain and pain interfering, moderately or more, with housework and other work.

Conclusion

Author Information

Megan Pledger, Senior Research Fellow; Greg Martin, Senior Research Fellow; Jacqueline Cumming, Professor of Health Policy and Management and Director, Health Services Research Centre, School of Government, Victoria University of Wellington, Wellington.

Acknowledgements

We thank the respondents of the New Zealand Health Survey, 2012/13 for their participation in the survey. Access to the data used in this study was provided by Statistics New Zealand under conditions designed to keep individual information secure in accordance with requirements of the Statistics Act 1975. The opinions presented are those of the authors and do not necessarily represent an official view of Statistics New Zealand.

Correspondence

Megan Pledger, Health Services Research Centre, School of Government, Victoria University of Wellington, PO Box 600, Wellington 6140.

Correspondence Email

Megan.Pledger@vuw.ac.nz

Competing Interests

- New Zealand Police. Illicit drugs - offences and penalties [Online]. Last accessed: 12 October 2015. Available at: http://www.police.govt.nz/advice/drugs-and-alcohol/illicit-drugs-offences-and-penalties Majurey E. Hope for Zoe in cannabis oil. Rotorua Daily Post [Online]. Last accessed: 9 October 2015. Available at: http://www.nzherald.co.nz/rotorua-daily-post/news/article.cfm?c_id= 1503438&objectid=11465386 Medsafe. Medsafe Product Detail - Sativex [Online]. Last accessed: 18 January 2016. Available at: http://www.medsafe.govt.nz/regulatory/ProductDetail.asp?ID=13391 Medsafe. Sativex\u00ae Oromucosal Spray - Requirements for Prescribers [Online]. Last accessed: 9 October 2015. Available at: http://www.medsafe.govt.nz/profs/RIss/Sativex.asp Ministry of Health (2013). Official Information Act response to the request for the number of requests and approvals for medicinal cannabis [Online]. Last accessed: 15 February, 2015. Available at: https://fyi.org.nz/request/3539/response/11315/attach/html/4/H20160%200118%20 Forsyth%20resp.pdf.html [Request made by Iain Forsyth, response dated 15 February 2016]. Stuff. Medical marijuana funding approved for Northland woman [Online]. Last accessed: 29 January 2016. Available at: http://www.stuff.co.nz/national/health/76355498/medical-marijuana-funding-approved-for-northland-woman Green Party of Aotearoa New Zealand. Drug Law Reform [Online]. Last accessed: 9 October 2015. Available at: https://home.greens.org.nz/sites/default/files/campaigns/cannabis/SurveyofDoctors.pdf New Zealand Parliament. Misuse of Drugs (Medicinal Cannabis) Amendment Bill [Online]. Last accessed: 9 October 2015. Available at: http://www.parliament.nz/en-nz/pb/legislation/bills/ 00DBHOH_BILL7386_1/misuse-of-drugs-medicinal-cannabis-amendment-bill Shadmi, H. Medical marijuana transforms into big business in Israel [Online]. Last accessed: 9 October 2015. Available at: http://www.haaretz.com/news/medical-marijuana-transforms-into-big-business-in-israel-1.278455 Health Canada. Medical Use of Marijuana - Drugs and Health Products [Online]. Last accessed: 9 October 2015. Available at: http://www.hc-sc.gc.ca/dhp-mps/marihuana/index-eng.php The Office of Medicinal Cannabis [Online]. Last accessed: 9 October 2015. Available at: https://www.cannabisbureau.nl/english ProCon.org. 23 Legal Medical Marijuana States and DC - Medical Marijuana [Online]. Last accessed: 9 October 2015. Available at: http://medicalmarijuana.procon.org/view.resource.php? resourceID=000881 CBS News: 60 Minutes. The Debate on California s Pot Shops [Online]. Last accessed: 11 January, 2016. Available at http://www.cbsnews.com/stories/2007/09/20/60minutes/main 3281715.shtml?source=search_story Ministry of Health. New Zealand Health Survey: Annual update of key findings 2012/13 [Online]. Ministry of Health. Last accessed: 9 October 2015. Available at: http://www.health.govt.nz/ publication/new-zealand-health-survey-annual-update-key-findings-2012-13 Research Triangle Institute. SUDAAN Language Manual, Release 9.0. Research Triangle Park, NC: Research Triangle Institute; 2004. Ministry of Health. A Portrait of Health: Key results of the 2002/03 New Zealand Health Survey [Online]. Last accessed: 29 January 2016. Available at: http://www.health.govt.nz/publication/ portrait-health-key-results-2002-03-new-zealand-health-survey Pledger MJ, Cumming JN. The Association of Marijuana with Cancer and Pain. Unpublished manuscript, Victoria University of Wellington, Wellington, New Zealand; 2010. Pledger MJ, Cumming JM, Burnette M. Health service use amongst users of complementary and alternative medicine. N Z Med J. 2010;123:26-35. Last accessed: 12 October 2015. Available at: https://www.nzma.org.nz/journal/read-the-journal/all-issues/2010-2019/2010/vol-123-no-1312/article-pledger-

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It is currently illegal to cultivate, possess, supply and use cannabis through the Misuse of Drugs Act 1975.1 However, the Minister of Health is able to approve the medical use of the cannabis plant, although in practice, the decision has been delegated to the Associate Health Minister Hon Peter Dunne.2 In 2015, the first application was approved for the use of cannabis oil for a case of status epilepticus.2 In the context of this application, Hon Peter Dunne said that this should not be seen as a significant change in policy.2In 2010, consent was given for use of the cannabis medicine, Sativex, in New Zealand.3 This medicine is an extract of the cannabis plant and is a standardised product with known levels of psychoactive content unlike illicit cannabis, which can vary greatly in potency.4 Sativex is available on application to the Ministry of Health by the patient, the patient s GP and specialist.4 Sativex is not fully funded by PHARMAC, and is relatively expensive compared to illicit cannabis.3 As of January 27 2016, 104 applications to prescribe Sativex had been approved in New Zealand.5 In the same month, a patient who had recurring seizures that her specialist said could lead to coma and death had the medicine fully funded.6As cannabis use is illegal, it is difficult to get information about who is using cannabis medicinally and for what reasons. In 2003, the Green Party of New Zealand randomly surveyed general practitioners and selected hospital specialists about their views on medicinal cannabis.7 The results showed that 20% of these doctors knew they had patients who were using cannabis medicinally. They also showed that 32% of doctors would consider prescribing medicinal cannabis products if they were legally allowed and 10% of doctors had patients they felt could benefit from cannabis.In 2006, the Green Party of New Zealand introduced the Misuse of Drugs (Medicinal Cannabis) Amendment Bill, but it was defeated in a conscience vote in 2009.8 However, other countries have legalised medicinal cannabis use, eg, Israel in 1996,9 Canada in 2001,10 and The Netherlands in 2003.11 In the US, medicinal cannabis use is illegal at the Federal level, but medicinal use of cannabis is currently legal in 23 states.12 In Canada and The Netherlands, the government supplies cannabis to users directly or through registered suppliers, allowing them to control quality and supply, whereas in the US, medical cannabis users have to grow or find their own supply, leading to a free market in cannabis.10,11,13 In California, where medicinal cannabis was legalised in 1996 through a citizen s initiative, any debilitating condition can be treated with cannabis if a physician recommends it.12 This has led to recreational users being able to access medicinal cannabis through misleading their doctor about their health, or with their doctor s cooperation.13Given the defeat of the Green Party s bill, legalisation of medicinal cannabis is unlikely to happen in New Zealand in the foreseeable future. This leaves practitioners with little information about who uses cannabis medicinally, and why. The aim of this study was to explore the characteristics of medicinal cannabis users using representative national survey data.MethodsConfidentialised, unit record data from the 2012/2013 New Zealand Health Survey were supplied by the Ministry of Health (MoH) with administration through Statistics New Zealand.14 The adult data set contains 13,009 respondents, aged 15 years and above, who were living in a private or non-private dwellings, and were from the New Zealand usually resident population. Non-private dwellings include such things as aged care accommodation and student hostels. However, people in hospitals, prisons, dementia units or those in hospital-level care accommodation were excluded, as well as people in meshblocks with sparse populations, and New Zealand s off-shore islands.The survey used a complex method of sampling that included the means of oversampling Mori, Asian and Pacific people, but the survey has been weighted to produce a representative sample. Estimates produced by these weights form unbiased estimates of population values. The data set also includes a set of 100 replicate weights which create 100 further estimates. The variance of these estimates around the unbiased estimate gives the sampling variance. For the purpose of this paper, SUDAAN was used to do these calculations.15Results can suffer from bias when the number of respondents that contribute to an estimate are too few, or an estimate may have little meaning if it has large sampling variation. The relative sampling error (RSE) is monitored to check if an estimate has these problems. The MoH advises that estimates with a RSE of 30%-50% should be used with caution, and estimates with RSE over 50% should be considered too unreliable for most practical purposes.14 In this article, estimates with RSE between 30% and 50% are marked with an asterisk, estimates over 50% are marked with a double asterisk, and estimates that rely on few respondents will be supressed, eg, an estimate of 6.4% with a RSE of 45% will be marked as 6.4*%.The New Zealand Health Surveys consist of a core questionnaire and rotating modules. In the core questionnaire, survey respondents were asked if they had used cannabis in the last 12 months for recreational or non-medical purposes, or to get high. In the 2012/13 survey, the tobacco, alcohol and drug use modules were also included, which asked questions about use of those products. Questions used from this module include: lifetime use of cannabis; cannabis use in the last 12 months; and whether cannabis was used in the last 12 months to intentionally treat a range of medical conditions pain, nausea, depression, anxiety/nerves, other, or none of these. These questions were used to assign people to a category of cannabis use: non-users respondents who had never used cannabis; ex-users respondents who had used cannabis but had not done so in the last year; last year users: non-medicinal respondents who had used cannabis in the last year, but who had not intentionally used it to treat a medical condition; last year users: medicinal respondents who had used cannabis in the last year, and had intentionally used it to treat a medical condition. Not all respondents could be assigned to a category, either because they had answered don t know, or refused to answer a particular question, or because their answer to the question from the core module disagreed with their answer to the questions in the drug use module. Whenever an assignment could not be made directly from the data, the following rules were used to make a classification, and they were done in this order: a) only use information from drug use module questions; b) use additional information from main module question if data is missing from drug module questions; c) any unresolved classification has data for the missing question to be treated as if they answered No. The classifications are outlined in Table 1. Table 2 shows the number of people classified into each group according to these rules.Table 1: Questions and answers used to classify cannabis users. Notes: 1 - All identical classifications are similarly coloured. 2- Non-italicised, bolded classifications are classifications where data is consistent and not missing; italicised classifications are either contradictory or have missing data. The following rules were used to define an italicised classification in this order: a) use information from drug module questions only; b) use additional information from main module question if data is missing from drug module questions; and c) any unresolved classification has data for the missing question to be treated as if they answered \"No\". Table 2: Count of Classifications by the rules applied. Non-Users Ex-Users Last Year Use non-Medicinal Last Year Use Medicinal Total Cumulative % classified No Rule 7,379 3,924 587 648 12,538 96.4 Rule a 42 129 153 0 324 98.9 Rule b 0 15 12 6 33 99.1 Rule c 94 3 17 0 114 100.0 Total 7,515 4,071 769 654 13,009 While people who answered don t know may be ambiguous as to their classification (eg, they could not remember if they had used cannabis 11 or 13 months ago, or didn t know if a herbal remedy contained cannabis), those people who refused were more likely to be respondents who ought to have answered yes, but were reluctant to do so; for example, they did not want to admit to a criminal offense. However, since respondents could also lie about use, the categories can be described as admitted use rather than actual use, and therefore are an undercount of actual use. The size of the groups get smaller when moving from classification 1 to 4 so that putting a respondent in a category with more respondents, rather than a category with fewer (eg, non-user, rather than ex-user), means they make a lesser contribution to the results.The data were analysed, and proportions, means and their 95% confidence intervals appear in the tables for all four groups, and are commented on in the results section. It is well known that cannabis users and non-cannabis users have different characteristics, however, little is known about the differences between medicinal and non-medicinal users of cannabis, so their responses were modelled, compared, and tested using p-values. If the responses were continuous, they were analysed using regression methods. If the responses were from a question with two or more options, they were analysed using multinomial logistic regression with a generalised logit link. In both cases, as there was only one class variable, the proportions or means presented in the tables were equivalent to the conditional marginal means outputted by these regression analyses. The difference between the conditional marginal means for groups 3 and 4 were tested, and the associated p-value appears in the tables. As age, sex and ethnicity are known to be associated with cannabis use, the models were re-run with these factors as confounders to see if that changed the interpretation of the differences; if so, this is mentioned.ResultsPrevalence in major demographic factorsOverall, 58.7% (57.7-59.8) of respondents were non-users, 30.2% (29.3-31.2) had used cannabis, but had not done so in the last year, while 6.5% (5.9-7.1) had used cannabis in the last year, but not medicinally, and 4.6% (4.1-5.1) had used it medicinally in the last year (see Table 3). Of the people using cannabis medicinally, 68.6% (61.5-75.0) had also used it recreationally, or for non-medicinal purposes, or to get high in the last year.Table 3: Prevalence of cannabis use across major demographic variables. Non-Users ex-Users Last Year Users: non-Medicinal Last Year Users: Medicinal p-value for difference between group 3 and 4 Statisitic 95% CI Statisitic 95% CI Statisitic 95% CI Statisitic 95% CI All 58.7 57.7-59.8 30.2 29.3-31.2 6.5 5.9-7.1 4.6 4.1-5.1 0.0000 Sex (row %) Female 62.3 60.8-63.8 29.8 28.4-31.2 4.5 3.9-5.3 3.3 2.8-3.9 0.0062 Male 54.9 53.4-56.4 30.7 29.2-32.2 8.5 7.6-9.5 5.9 5.2-6.8 0.0001 Age Mean 48.9 48.5-49.2 42.1 41.6-42.6 30.7 29.8-31.7 33.1 31.8-34.4 0.0063 Age Group (row %) 15-24 56.6 53.8-59.4 19.9 17.7-22.2 14.7 12.6-17.0 8.8 7.3-10.6 0.0000 25-34 43.4 40.3-46.5 38.7 35.7-41.7 10.4 8.6-12.6 7.5 6.1-9.2 0.0222 35-44 46.0 42.9-49.1 43.3 40.1-46.5 6.5 5.3-7.9 4.3 3.4-5.3 0.0057 45-54 49.9 47.4-52.5 41.6 39.1-44.2 4.3 3.5-5.2 4.2 3.3-5.4 0.9412 55+ 79.3 77.8-80.6 18.8 17.4-20.2 0.9 0.7-1.3 1.1 0.7-1.6 0.6226 Ethnicity (row %) Mori 36.3 33.6-39.0 39.1 36.6-41.6 14.5 12.5-16.7 10.2 8.7-12.0 0.0016 Pacific people 68.2 63.3-72.7 24.7 20.6-29.4 4.9 * 3.2-7.6 2.2 * 1.3-3.5 0.0257 Asian 91.1 88.5-93.1 6.3 4.8-8.2 - - - - - European/Other 57.0 55.7-58.3 32.8 31.6-34.1 5.8 5.2-6.6 4.4 3.8-5.1 0.0029 Notes: 1 - an estimate with RSE between 30% and 50% will be marked with an asterisk, estimates with RSE over 50% will be marked with a double asterisk and estimates that rely on a few respondents will be suppressed.SexNon-users were more likely to be female than male (54.5% (53.5-55.4) vs 45.5% (44.6-46.5), respectively), ex-users were more evenly split (male 50.8% (48.8-52.4), female 49.4% (47.7-51.2)), and last year users were more likely to be male, whether medicinal users (62.9% (57.9-67.6)) or non-medicinal users (63.9% (59.6-67.9)). Of the people using cannabis for medicinal purposes only, 61.0% (51.7-69.7) were male.AgeNine percent (8.8% (7.3-10.6)) of 15-24-year-olds said they used cannabis for medicinal reasons, and 14.7% (12.6-17.0) had used it non-medicinally. This age group had the largest proportion of both types of users. They were also the group with the second largest proportion of respondents who have never used cannabis (56.6% (53.8-59.4)), behind the oldest age group, 55+ years, with 79.3% (77.8-80.6). The proportion of those who have never used cannabis in the three middle age groups lies between 43% and 49%.Prioritised ethnicityTen percent of Mori reported using cannabis medicinally (10.2% (8.7-12.0)) and 14.5% (12.5-16.7) reported using cannabis non-medicinally. Mori have the highest rates of medicinal and non-medicinal use and also ex-use (39.1% (36.6-41.6)). However, European New Zealanders/Others make up 64.3% (60.2-68.2) of non-medicinal users and 67.9% (62.7-72.6) of medicinal users.Demographic factors associated with medicinal use amongst cannabis usersMedicinal users of cannabis were more likely to have no school qualification (33.7% (29.1-38.7)) compared to non-medicinal users (24.9% (21.5-28.7)), and less likely to have qualifications from Year 13/Form 7 (see Table 4).Table 4: Demographic information about Cannabis users and non-users. Non-Users ex-Users Last Year Users: non-Medicinal Last Year Users: Medicinal p-value for difference between group 3 and 4 Statisitic 95% CI Statisitic 95% CI Statisitic 95% CI Statisitic 95% CI School Qualifications (col %) None 27.1 25.6-28.8 21.3 19.7-23.0 24.9 21.5-28.7 33.7 29.1-38.7 0.0056 Year 11/ Form 5 17.7 16.5-18.9 20.3 18.6-22.0 21.5 17.8-25.8 23.3 18.0-29.6 0.6304 Year 12/ Form 6 16.2 14.9-17.6 23.4 21.5-25.4 21.8 17.9-26.3 21.6 17.2-26.7 0.9473 Year 13/ Form 7 17.0 15.7-18.4 26.0 23.8-28.2 27.4 22.4-33.0 16.0 12.2-20.6 0.0008 Non-NZ qualification 22.0 20.6-23.5 9.1 7.6-10.8 4.4 2.7-6.9 5.4 3.4-8.6 0.5171 New Zealand Deprivation Index 2006 (col %) Deciles 1 & 2 (least deprived) 21.1 20.0-22.3 21.7 20.1-23.5 11.3 * 7.7-16.4 14.2 * 10.0-19.8 0.3088 Deciles 3 & 4 21.5 20.3-22.8 20.3 18.7-22.1 19.6 15.5-24.5 11.7 * 8.2-16.4 0.0028 Deciles 5 & 6 20.1 19.0-21.2 19.9 18.5-21.4 23.5 18.7-29.1 20.8 15.5-27.4 0.5215 Deciles 7 & 8 19.9 19.0-20.8 19.9 18.8-21.0 21.8 18.3-25.7 21.2 16.9-26.2 0.8464 Deciles 9 & 10 (most deprived) 17.4 16.5-18.3 18.2 16.9-19.5 23.7 20.3-27.5 32.1 27.5-37.0 0.0025 Household No of adults (mean) 2.5 2.5-2.6 2.4 2.4-2.5 2.9 2.8-3.1 2.7 2.6-2.8 0.0022 No of children (mean) 0.6 0.5-0.6 0.8 0.8-0.8 0.8 0.7-0.9 0.7 0.6-0.8 0.1665 Income Source (%) Income from employer1 52.3 50.9-53.8 69.2 67.0-71.3 70.4 66.2-74.3 65.0 59.9-69.8 0.0899 Invalids/sickness/ accident benefits2 3.5 3.1-4.0 5.3 4.5-6.2 7.0 4.8-10.0 16.8 13.6-20.5 0.0000 Self-employment3 11.1 9.9-12.3 18.5 16.8-20.3 10.6 * 7.7-14.4 9.8 7.2-13.2 0.7488 Unemployment benefit 1.2 0.9-1.6 1.7 1.3-2.1 7.1 5.3-9.5 9.3 * 6.5-13.0 0.2491 Domestic purposes benefit 1.5 1.2-1.8 4.6 3.9-5.3 4.3 3.3-5.8 7.5 5.9-9.4 0.0041 Student allowance 2.5 2.0-3.1 3.0 2.3-4.0 9.2 * 6.2-13.6 6.5 * 4.3-9.5 0.1976 Interest/dividends/ rents/other investments 14.2 12.5-16.1 14.2 12.2-16.4 8.1 * 5.6-11.6 2.9 ** 1.5-5.6 0.0063 Retirement age benefits4 25.8 25.0-26.6 5.3 4

Summary

Abstract

Aim

To explore the characteristics of medicinal and non-medicinal cannabis users, and the conditions that were treated with cannabis.

Method

The data comes from the New Zealand Health Survey 2012/2013, which sampled 13,009 people, aged 15+ years, living in private or non-private dwellings in New Zealand. Participants self-reported cannabis use and were put into groups: 1) non-users; 2) ex-users; 3) last year users non-medicinal; 4) last-year users medicinal. Prevalence was reported for the major demographic subgroups; sex, age and ethnicity. Regression models were then used to find associations between demographic characteristics and cannabis use for groups 3 and 4.

Results

About five percent (4.6%, 95% CI 4.1-5.1) of those aged 15+ report using cannabis medicinally. This use was associated with being male, younger, less well-educated and relatively poor. While Mori have the highest prevalence of medicinal use, European NZ/Others make up 67.9% (95% CI 62.7-72.6) of medicinal users. Reported medicinal use was associated with reported conditions that were typically hard to manage: pain, anxiety/nerves and depression. Medicinal users were more likely to report chronic pain and pain interfering, moderately or more, with housework and other work.

Conclusion

Author Information

Megan Pledger, Senior Research Fellow; Greg Martin, Senior Research Fellow; Jacqueline Cumming, Professor of Health Policy and Management and Director, Health Services Research Centre, School of Government, Victoria University of Wellington, Wellington.

Acknowledgements

We thank the respondents of the New Zealand Health Survey, 2012/13 for their participation in the survey. Access to the data used in this study was provided by Statistics New Zealand under conditions designed to keep individual information secure in accordance with requirements of the Statistics Act 1975. The opinions presented are those of the authors and do not necessarily represent an official view of Statistics New Zealand.

Correspondence

Megan Pledger, Health Services Research Centre, School of Government, Victoria University of Wellington, PO Box 600, Wellington 6140.

Correspondence Email

Megan.Pledger@vuw.ac.nz

Competing Interests

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It is currently illegal to cultivate, possess, supply and use cannabis through the Misuse of Drugs Act 1975.1 However, the Minister of Health is able to approve the medical use of the cannabis plant, although in practice, the decision has been delegated to the Associate Health Minister Hon Peter Dunne.2 In 2015, the first application was approved for the use of cannabis oil for a case of status epilepticus.2 In the context of this application, Hon Peter Dunne said that this should not be seen as a significant change in policy.2In 2010, consent was given for use of the cannabis medicine, Sativex, in New Zealand.3 This medicine is an extract of the cannabis plant and is a standardised product with known levels of psychoactive content unlike illicit cannabis, which can vary greatly in potency.4 Sativex is available on application to the Ministry of Health by the patient, the patient s GP and specialist.4 Sativex is not fully funded by PHARMAC, and is relatively expensive compared to illicit cannabis.3 As of January 27 2016, 104 applications to prescribe Sativex had been approved in New Zealand.5 In the same month, a patient who had recurring seizures that her specialist said could lead to coma and death had the medicine fully funded.6As cannabis use is illegal, it is difficult to get information about who is using cannabis medicinally and for what reasons. In 2003, the Green Party of New Zealand randomly surveyed general practitioners and selected hospital specialists about their views on medicinal cannabis.7 The results showed that 20% of these doctors knew they had patients who were using cannabis medicinally. They also showed that 32% of doctors would consider prescribing medicinal cannabis products if they were legally allowed and 10% of doctors had patients they felt could benefit from cannabis.In 2006, the Green Party of New Zealand introduced the Misuse of Drugs (Medicinal Cannabis) Amendment Bill, but it was defeated in a conscience vote in 2009.8 However, other countries have legalised medicinal cannabis use, eg, Israel in 1996,9 Canada in 2001,10 and The Netherlands in 2003.11 In the US, medicinal cannabis use is illegal at the Federal level, but medicinal use of cannabis is currently legal in 23 states.12 In Canada and The Netherlands, the government supplies cannabis to users directly or through registered suppliers, allowing them to control quality and supply, whereas in the US, medical cannabis users have to grow or find their own supply, leading to a free market in cannabis.10,11,13 In California, where medicinal cannabis was legalised in 1996 through a citizen s initiative, any debilitating condition can be treated with cannabis if a physician recommends it.12 This has led to recreational users being able to access medicinal cannabis through misleading their doctor about their health, or with their doctor s cooperation.13Given the defeat of the Green Party s bill, legalisation of medicinal cannabis is unlikely to happen in New Zealand in the foreseeable future. This leaves practitioners with little information about who uses cannabis medicinally, and why. The aim of this study was to explore the characteristics of medicinal cannabis users using representative national survey data.MethodsConfidentialised, unit record data from the 2012/2013 New Zealand Health Survey were supplied by the Ministry of Health (MoH) with administration through Statistics New Zealand.14 The adult data set contains 13,009 respondents, aged 15 years and above, who were living in a private or non-private dwellings, and were from the New Zealand usually resident population. Non-private dwellings include such things as aged care accommodation and student hostels. However, people in hospitals, prisons, dementia units or those in hospital-level care accommodation were excluded, as well as people in meshblocks with sparse populations, and New Zealand s off-shore islands.The survey used a complex method of sampling that included the means of oversampling Mori, Asian and Pacific people, but the survey has been weighted to produce a representative sample. Estimates produced by these weights form unbiased estimates of population values. The data set also includes a set of 100 replicate weights which create 100 further estimates. The variance of these estimates around the unbiased estimate gives the sampling variance. For the purpose of this paper, SUDAAN was used to do these calculations.15Results can suffer from bias when the number of respondents that contribute to an estimate are too few, or an estimate may have little meaning if it has large sampling variation. The relative sampling error (RSE) is monitored to check if an estimate has these problems. The MoH advises that estimates with a RSE of 30%-50% should be used with caution, and estimates with RSE over 50% should be considered too unreliable for most practical purposes.14 In this article, estimates with RSE between 30% and 50% are marked with an asterisk, estimates over 50% are marked with a double asterisk, and estimates that rely on few respondents will be supressed, eg, an estimate of 6.4% with a RSE of 45% will be marked as 6.4*%.The New Zealand Health Surveys consist of a core questionnaire and rotating modules. In the core questionnaire, survey respondents were asked if they had used cannabis in the last 12 months for recreational or non-medical purposes, or to get high. In the 2012/13 survey, the tobacco, alcohol and drug use modules were also included, which asked questions about use of those products. Questions used from this module include: lifetime use of cannabis; cannabis use in the last 12 months; and whether cannabis was used in the last 12 months to intentionally treat a range of medical conditions pain, nausea, depression, anxiety/nerves, other, or none of these. These questions were used to assign people to a category of cannabis use: non-users respondents who had never used cannabis; ex-users respondents who had used cannabis but had not done so in the last year; last year users: non-medicinal respondents who had used cannabis in the last year, but who had not intentionally used it to treat a medical condition; last year users: medicinal respondents who had used cannabis in the last year, and had intentionally used it to treat a medical condition. Not all respondents could be assigned to a category, either because they had answered don t know, or refused to answer a particular question, or because their answer to the question from the core module disagreed with their answer to the questions in the drug use module. Whenever an assignment could not be made directly from the data, the following rules were used to make a classification, and they were done in this order: a) only use information from drug use module questions; b) use additional information from main module question if data is missing from drug module questions; c) any unresolved classification has data for the missing question to be treated as if they answered No. The classifications are outlined in Table 1. Table 2 shows the number of people classified into each group according to these rules.Table 1: Questions and answers used to classify cannabis users. Notes: 1 - All identical classifications are similarly coloured. 2- Non-italicised, bolded classifications are classifications where data is consistent and not missing; italicised classifications are either contradictory or have missing data. The following rules were used to define an italicised classification in this order: a) use information from drug module questions only; b) use additional information from main module question if data is missing from drug module questions; and c) any unresolved classification has data for the missing question to be treated as if they answered \"No\". Table 2: Count of Classifications by the rules applied. Non-Users Ex-Users Last Year Use non-Medicinal Last Year Use Medicinal Total Cumulative % classified No Rule 7,379 3,924 587 648 12,538 96.4 Rule a 42 129 153 0 324 98.9 Rule b 0 15 12 6 33 99.1 Rule c 94 3 17 0 114 100.0 Total 7,515 4,071 769 654 13,009 While people who answered don t know may be ambiguous as to their classification (eg, they could not remember if they had used cannabis 11 or 13 months ago, or didn t know if a herbal remedy contained cannabis), those people who refused were more likely to be respondents who ought to have answered yes, but were reluctant to do so; for example, they did not want to admit to a criminal offense. However, since respondents could also lie about use, the categories can be described as admitted use rather than actual use, and therefore are an undercount of actual use. The size of the groups get smaller when moving from classification 1 to 4 so that putting a respondent in a category with more respondents, rather than a category with fewer (eg, non-user, rather than ex-user), means they make a lesser contribution to the results.The data were analysed, and proportions, means and their 95% confidence intervals appear in the tables for all four groups, and are commented on in the results section. It is well known that cannabis users and non-cannabis users have different characteristics, however, little is known about the differences between medicinal and non-medicinal users of cannabis, so their responses were modelled, compared, and tested using p-values. If the responses were continuous, they were analysed using regression methods. If the responses were from a question with two or more options, they were analysed using multinomial logistic regression with a generalised logit link. In both cases, as there was only one class variable, the proportions or means presented in the tables were equivalent to the conditional marginal means outputted by these regression analyses. The difference between the conditional marginal means for groups 3 and 4 were tested, and the associated p-value appears in the tables. As age, sex and ethnicity are known to be associated with cannabis use, the models were re-run with these factors as confounders to see if that changed the interpretation of the differences; if so, this is mentioned.ResultsPrevalence in major demographic factorsOverall, 58.7% (57.7-59.8) of respondents were non-users, 30.2% (29.3-31.2) had used cannabis, but had not done so in the last year, while 6.5% (5.9-7.1) had used cannabis in the last year, but not medicinally, and 4.6% (4.1-5.1) had used it medicinally in the last year (see Table 3). Of the people using cannabis medicinally, 68.6% (61.5-75.0) had also used it recreationally, or for non-medicinal purposes, or to get high in the last year.Table 3: Prevalence of cannabis use across major demographic variables. Non-Users ex-Users Last Year Users: non-Medicinal Last Year Users: Medicinal p-value for difference between group 3 and 4 Statisitic 95% CI Statisitic 95% CI Statisitic 95% CI Statisitic 95% CI All 58.7 57.7-59.8 30.2 29.3-31.2 6.5 5.9-7.1 4.6 4.1-5.1 0.0000 Sex (row %) Female 62.3 60.8-63.8 29.8 28.4-31.2 4.5 3.9-5.3 3.3 2.8-3.9 0.0062 Male 54.9 53.4-56.4 30.7 29.2-32.2 8.5 7.6-9.5 5.9 5.2-6.8 0.0001 Age Mean 48.9 48.5-49.2 42.1 41.6-42.6 30.7 29.8-31.7 33.1 31.8-34.4 0.0063 Age Group (row %) 15-24 56.6 53.8-59.4 19.9 17.7-22.2 14.7 12.6-17.0 8.8 7.3-10.6 0.0000 25-34 43.4 40.3-46.5 38.7 35.7-41.7 10.4 8.6-12.6 7.5 6.1-9.2 0.0222 35-44 46.0 42.9-49.1 43.3 40.1-46.5 6.5 5.3-7.9 4.3 3.4-5.3 0.0057 45-54 49.9 47.4-52.5 41.6 39.1-44.2 4.3 3.5-5.2 4.2 3.3-5.4 0.9412 55+ 79.3 77.8-80.6 18.8 17.4-20.2 0.9 0.7-1.3 1.1 0.7-1.6 0.6226 Ethnicity (row %) Mori 36.3 33.6-39.0 39.1 36.6-41.6 14.5 12.5-16.7 10.2 8.7-12.0 0.0016 Pacific people 68.2 63.3-72.7 24.7 20.6-29.4 4.9 * 3.2-7.6 2.2 * 1.3-3.5 0.0257 Asian 91.1 88.5-93.1 6.3 4.8-8.2 - - - - - European/Other 57.0 55.7-58.3 32.8 31.6-34.1 5.8 5.2-6.6 4.4 3.8-5.1 0.0029 Notes: 1 - an estimate with RSE between 30% and 50% will be marked with an asterisk, estimates with RSE over 50% will be marked with a double asterisk and estimates that rely on a few respondents will be suppressed.SexNon-users were more likely to be female than male (54.5% (53.5-55.4) vs 45.5% (44.6-46.5), respectively), ex-users were more evenly split (male 50.8% (48.8-52.4), female 49.4% (47.7-51.2)), and last year users were more likely to be male, whether medicinal users (62.9% (57.9-67.6)) or non-medicinal users (63.9% (59.6-67.9)). Of the people using cannabis for medicinal purposes only, 61.0% (51.7-69.7) were male.AgeNine percent (8.8% (7.3-10.6)) of 15-24-year-olds said they used cannabis for medicinal reasons, and 14.7% (12.6-17.0) had used it non-medicinally. This age group had the largest proportion of both types of users. They were also the group with the second largest proportion of respondents who have never used cannabis (56.6% (53.8-59.4)), behind the oldest age group, 55+ years, with 79.3% (77.8-80.6). The proportion of those who have never used cannabis in the three middle age groups lies between 43% and 49%.Prioritised ethnicityTen percent of Mori reported using cannabis medicinally (10.2% (8.7-12.0)) and 14.5% (12.5-16.7) reported using cannabis non-medicinally. Mori have the highest rates of medicinal and non-medicinal use and also ex-use (39.1% (36.6-41.6)). However, European New Zealanders/Others make up 64.3% (60.2-68.2) of non-medicinal users and 67.9% (62.7-72.6) of medicinal users.Demographic factors associated with medicinal use amongst cannabis usersMedicinal users of cannabis were more likely to have no school qualification (33.7% (29.1-38.7)) compared to non-medicinal users (24.9% (21.5-28.7)), and less likely to have qualifications from Year 13/Form 7 (see Table 4).Table 4: Demographic information about Cannabis users and non-users. Non-Users ex-Users Last Year Users: non-Medicinal Last Year Users: Medicinal p-value for difference between group 3 and 4 Statisitic 95% CI Statisitic 95% CI Statisitic 95% CI Statisitic 95% CI School Qualifications (col %) None 27.1 25.6-28.8 21.3 19.7-23.0 24.9 21.5-28.7 33.7 29.1-38.7 0.0056 Year 11/ Form 5 17.7 16.5-18.9 20.3 18.6-22.0 21.5 17.8-25.8 23.3 18.0-29.6 0.6304 Year 12/ Form 6 16.2 14.9-17.6 23.4 21.5-25.4 21.8 17.9-26.3 21.6 17.2-26.7 0.9473 Year 13/ Form 7 17.0 15.7-18.4 26.0 23.8-28.2 27.4 22.4-33.0 16.0 12.2-20.6 0.0008 Non-NZ qualification 22.0 20.6-23.5 9.1 7.6-10.8 4.4 2.7-6.9 5.4 3.4-8.6 0.5171 New Zealand Deprivation Index 2006 (col %) Deciles 1 & 2 (least deprived) 21.1 20.0-22.3 21.7 20.1-23.5 11.3 * 7.7-16.4 14.2 * 10.0-19.8 0.3088 Deciles 3 & 4 21.5 20.3-22.8 20.3 18.7-22.1 19.6 15.5-24.5 11.7 * 8.2-16.4 0.0028 Deciles 5 & 6 20.1 19.0-21.2 19.9 18.5-21.4 23.5 18.7-29.1 20.8 15.5-27.4 0.5215 Deciles 7 & 8 19.9 19.0-20.8 19.9 18.8-21.0 21.8 18.3-25.7 21.2 16.9-26.2 0.8464 Deciles 9 & 10 (most deprived) 17.4 16.5-18.3 18.2 16.9-19.5 23.7 20.3-27.5 32.1 27.5-37.0 0.0025 Household No of adults (mean) 2.5 2.5-2.6 2.4 2.4-2.5 2.9 2.8-3.1 2.7 2.6-2.8 0.0022 No of children (mean) 0.6 0.5-0.6 0.8 0.8-0.8 0.8 0.7-0.9 0.7 0.6-0.8 0.1665 Income Source (%) Income from employer1 52.3 50.9-53.8 69.2 67.0-71.3 70.4 66.2-74.3 65.0 59.9-69.8 0.0899 Invalids/sickness/ accident benefits2 3.5 3.1-4.0 5.3 4.5-6.2 7.0 4.8-10.0 16.8 13.6-20.5 0.0000 Self-employment3 11.1 9.9-12.3 18.5 16.8-20.3 10.6 * 7.7-14.4 9.8 7.2-13.2 0.7488 Unemployment benefit 1.2 0.9-1.6 1.7 1.3-2.1 7.1 5.3-9.5 9.3 * 6.5-13.0 0.2491 Domestic purposes benefit 1.5 1.2-1.8 4.6 3.9-5.3 4.3 3.3-5.8 7.5 5.9-9.4 0.0041 Student allowance 2.5 2.0-3.1 3.0 2.3-4.0 9.2 * 6.2-13.6 6.5 * 4.3-9.5 0.1976 Interest/dividends/ rents/other investments 14.2 12.5-16.1 14.2 12.2-16.4 8.1 * 5.6-11.6 2.9 ** 1.5-5.6 0.0063 Retirement age benefits4 25.8 25.0-26.6 5.3 4

Summary

Abstract

Aim

To explore the characteristics of medicinal and non-medicinal cannabis users, and the conditions that were treated with cannabis.

Method

The data comes from the New Zealand Health Survey 2012/2013, which sampled 13,009 people, aged 15+ years, living in private or non-private dwellings in New Zealand. Participants self-reported cannabis use and were put into groups: 1) non-users; 2) ex-users; 3) last year users non-medicinal; 4) last-year users medicinal. Prevalence was reported for the major demographic subgroups; sex, age and ethnicity. Regression models were then used to find associations between demographic characteristics and cannabis use for groups 3 and 4.

Results

About five percent (4.6%, 95% CI 4.1-5.1) of those aged 15+ report using cannabis medicinally. This use was associated with being male, younger, less well-educated and relatively poor. While Mori have the highest prevalence of medicinal use, European NZ/Others make up 67.9% (95% CI 62.7-72.6) of medicinal users. Reported medicinal use was associated with reported conditions that were typically hard to manage: pain, anxiety/nerves and depression. Medicinal users were more likely to report chronic pain and pain interfering, moderately or more, with housework and other work.

Conclusion

Author Information

Megan Pledger, Senior Research Fellow; Greg Martin, Senior Research Fellow; Jacqueline Cumming, Professor of Health Policy and Management and Director, Health Services Research Centre, School of Government, Victoria University of Wellington, Wellington.

Acknowledgements

We thank the respondents of the New Zealand Health Survey, 2012/13 for their participation in the survey. Access to the data used in this study was provided by Statistics New Zealand under conditions designed to keep individual information secure in accordance with requirements of the Statistics Act 1975. The opinions presented are those of the authors and do not necessarily represent an official view of Statistics New Zealand.

Correspondence

Megan Pledger, Health Services Research Centre, School of Government, Victoria University of Wellington, PO Box 600, Wellington 6140.

Correspondence Email

Megan.Pledger@vuw.ac.nz

Competing Interests

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