Inflammatory bowel disease (IBD) includes Crohn’s disease (CD) and ulcerative colitis (UC), two chronic diseases of the gastrointestinal system. They are thought to be caused by a combination of genetic predisposition, environmental triggers and immune responses that culminate in a poorly controlled inflammatory response.¹ Patients typically experience flare-ups followed by symptom-free periods. The most common symptoms include diarrhoea, fatigue and abdominal pain.² Quality of life is reduced in patients with IBD compared to controls.³ Improved insights into the pathogenesis of IBD4 have led to the development of new medical therapies. Current therapies include aminosalicylates, antibiotics, corticosteroids, immunomodulators and biologic medications. Despite treatment, many patients continue to experience symptoms or adverse effects as a result of taking these medications.⁵ Hence patients may seek alternative treatments to manage their symptoms, and some have identified cannabis as an option.⁵

Cannabis is the most widely used illegal drug in New Zealand and worldwide.⁶ A 2012/2013 survey re-ported that 42% of New Zealand adults aged 15 and over used cannabis at some point in their lifetime and 11% used cannabis over the previous 12 months.⁷ Forty two percent of those who used cannabis reported that their use in the previous year was for medicinal purposes.⁷ Currently, Sativex (a combination of cannabidiol and tetrahydrocannabinol) (GW Pharmaceuticals) and cannabidiol (CBD) products (defined as >98% CBD and containing no other controlled drug or active ingredient)⁸ can be prescribed in New Zealand, with certain restrictions.^9,10 There is an increasing interest in cannabinoids as an alter-native medicinal resource for patients with chronic disease.¹¹

Large-scale observational studies based in the US showed that patients with IBD were more likely to have tried cannabis than controls,¹² and that many were using medicinal and/or recreational cannabis for symptom management.¹³ A plausible biological mechanism by which cannabis could be beneficial for those with IBD is the body’s endocannabinoid system. Both endogenous and exogenous canna-binoids have been shown to interact with receptors in the gastrointestinal tract that are involved in regulating motility, secretions and inflammation.^14–18

However, randomised controlled trial (RCT) evidence on the efficacy of cannabinoid products in IBD is limited. Several small RCTs reported no significant difference in remission rates between intervention and control groups,^19–21 although a significant improvement in pain and appetite with THC-containing cigarettes in patients with CD was noted in one study,¹⁹ and an improvement in patient-reported quality of life with CBD extract was reported in a multi-centre RCT of UC patients.²¹ Overall, these RCTs have included small numbers of participants and used different formulations of cannabis, different types of IBD and different concentrations of active components, which makes comparisons difficult. Recent Cochrane reviews concluded that there was insufficient evidence that cannabis and canna-binoids were either efficacious or safe for treating UC or CD.^22,23

There are unanswered questions regarding how many patients with IBD in New Zealand are using cannabis, and how effective they consider cannabis to be. Our anonymous survey aimed to investigate the attitudes towards, use of and perceived effects of medicinal cannabinoids by people with IBD. This should help inform the upcoming referendum regarding the legalisation of cannabis for personal use in New Zealand,²⁴ by providing perspectives from patients with IBD. Our study will also be of interest to New Zealand clinicians who may be in a position to prescribe cannabinoid products to patients with IBD in the future.

Methods

Approval for this study was obtained from the University of Otago Human Ethics Committee (Health) (reference H20/017). Māori consultation was undertaken with the Ngāi Tahu Research Consultation Committee as part of the research ethics process.

Population

The source population was self-reported adult (18 years and older) New Zealand patients with a con-firmed IBD diagnosis. Data were collected between 7–19 February 2020 using an anonymous online questionnaire through the LimeSurvey platform. The survey was advertised using(a) invitations mailed to 444 known patients with IBD (identified via the Southern District Health Board (SDHB) gastroenterology department database) and (b) via the online advertising of the patient support organisation Crohn’s and Colitis New Zealand (CCNZ). Specifically, we advertised the study via the CCNZ website, Facebook page and email list. Informed consent was obtained before the completion of the online questionnaire.

The survey was unintentionally shared on a New Zealand medicinal cannabis awareness Facebook group, but it was removed from there within 24 hours. Due to questions on participants’ district health boards (DHBs) and types of survey invitation (mailed or online), we were able to identify known pa-tients with IBD from the Dunedin database (the ‘SDHB Letter Group’), and hence we could compare their responses with the rest of the sample. Further details regarding this analysis are found in Appendix Figure 1.

Analysis

Once the survey closed on the 19 February 2020, the data were exported from the LimeSurvey plat-form to a Microsoft Excel datasheet. Ineligible responses were removed: those that did not meet or did not answer questions about inclusion criteria (ie, they were younger than 18 or did not have a con-firmed diagnosis of IBD). The analysis was done using Microsoft Excel and Stata. To investigate whether there were any differences between the SDHB Letter Group responses and other responses on cannabis use, reported symptom relief from cannabis use or intention to use cannabis if it was legalised, these groups were compared using Chi-squared tests. Chi-squared tests were also used to test for differences in proportions between the categorical variables of interest. Where there were concerns about the distribution assumptions Fisher’s exact test was used. Independent samples t-tests were used to compare the average age of cannabis users to non-users.

Results

In total, there were 378 participants recruited over a 12-day period. Among those, 89% (334) were included in the analysis. Of these 334, 87 identified as residing in the SDHB region and were recruited via postal mail. Hence the response rate among in the 444 who were mailed invitations was 19.6% (87/444). Comparative analyses with that group of 87 confirmed that there was likely no contamination of the results from those taking part via other social media sources. In particular, there was no evidence of differences in cannabis use, reported symptom relief from cannabis use or intention to use cannabis if it was legal. Therefore, it was considered reasonable to use data from the whole group (n=334) for the analysis. Demographic characteristics of the responders are shown in Table 1.

Table 1: Demographics of respondents.

Participants were predominantly New Zealand European (84%) and female (71%). Sixty-one percent (192) had Crohn’s Disease, and 34% (108) had ulcerative colitis. Twenty-seven percent of respondents reported their disease as mild, 34% as moderate, 13% as severe and 26% as in remission. Thirty-seven percent reported a mild impact on their lives, 43% a moderate impact, 14% a severe impact and 6% no impact.

The most prevalent reported symptoms from the previous six months were tiredness and fatigue (82%), abdominal pain and cramps (74%), urgency (63%) and frequent diarrhoea (54%). Other symptoms included nausea and vomiting (45%), loss of appetite (40%) and fevers (21%).

Cannabis use

Fifty-one percent of respondents (160 people) reported having ever used cannabis. Forty-nine percent of those with CD and 52% of those with UC reported prior use (Pearson Chi2(2)=1.18, P=0.55, Fisher’s exact p-value=0.10). There was no evidence of a difference in the proportion of males who had used cannabis (57%) compared to females (48%) (P=0.15). Those who had used cannabis were, on average, 6.4 years younger than those who had not (95% CI 3.1 to 9.7, P=0.0002). Although use was higher among Māori participants (60%) than New Zealand Europeans (50%), there was no evidence of a statistical difference (Fisher’s exact p-value=0.86).

There was evidence of a difference in cannabis used by smoking status. In current smokers, the use of cannabis was higher (81%) than those who were ex-smokers (63%) or never smokers (36%) (Pearson Chi2(3)=36.0, P<0.005, Fisher’s exact p-value<0.001). There was also evidence that those who drank alcohol had higher cannabis use (57%) than those who did not drink (45%) (Pearson Chi2(2)=9.45, P=0.0009, Fisher’s exact p-value=0.005).

Cannabis use was highest among those who were unemployed (73%), followed by the self-employed (71%), those on the benefit (55%), paid employment and students (both 50%) and retirees (9%) (Pear-son Chi2(6)=33.7, P<0.001, Fisher’s exact p-value=0.000). There was no evidence of a difference in time since the onset of IBD between cannabis users and non-users.

Recreation was the most common reason for cannabis use (63%), and 38% reported use for social reasons. Forty-one percent of respondents reported relief of IBD symptoms with cannabis use, and 31% reported improved sleep. Other reasons for cannabis use included coping with IBD aside from symptom relief (15%), improvement in other medical conditions (13%) and being able to use less prescribed medication (12%).

The main reported route of administration for cannabis was inhaled (77%), such as joints (35%), bongs (15%), pipes (15%), vaporisers (6%) and mixed with tobacco (6%). Other routes of administration of cannabis included cooked and eaten (11%), oil capsule (7%), tincture or tea (3%) and balm (3%).

Participants mainly obtained cannabis from friends and relatives (54%) or bought it from someone else (36%). Nine percent grew their own and just 1% accessed cannabis products on prescription from a doctor.

Cannabis use in IBD

There was no evidence of a difference in having ever used cannabis for those who currently had IBD symptoms (52%) compared to those who did not (32%) (Pearson Chi2(1)=2.94, P=0.09, Fisher’s exact p-value=0.10). When comparing use in those experiencing specific symptoms, use was similar across all symptoms (Table 2). Diarrhoea, loss of appetite and fatigue were the only symptoms associated with a significantly larger proportion of those experiencing these symptoms using cannabis (Table 2).

Table 2: Use of cannabis in the last six months by IBD symptom.

Effects of cannabis

Among those who had used cannabis, 74% of users reported an improvement in quality of life: 25% “very much improved”, 26% “moderately improved” and 22% “somewhat improved”.

Among those who did not use cannabis, the main reason cited was the illegality of cannabis (63%). Other reasons included believing cannabis was not good for them (28%), accessibility (26%), cost (6%) and worsening IBD symptoms (2%). Twenty-five percent reported “other” reasons for not using cannabis, which included worsening anxiety and paranoia, not wanting to risk interactions with other medications and not enjoying the feeling of being “high”.

A variety of symptoms was reported to be improved by the use of cannabis by patients. The symptoms most reported as improved by cannabis use were abdominal pain/cramps (96%), loss of appetite (80%) and nausea and vomiting (79%) (Table 3). Overall, of the 66 respondents who reported using cannabis to help them deal with symptoms, 59 (89%) considered that it did help relieve symptoms, and five (8%) did not know. Specific symptoms that were affected by the use of cannabis are included in Table 3.

Table 3: Effects of cannabis on IBD symptoms.

Attitudes

Fifty-four percent of participants reported that, if cannabis were legal, they would request it for medicinal use to manage their symptoms. A further 15% reported that they would not request cannabis, and 35% said they did not know.

A similar distribution of responses was shown for intentions regarding the upcoming referendum for the legalisation of cannabis in New Zealand. Sixty-one percent of participants reported that they would support legalisation, 17% reported they would not and 21% were unsure.  

Discussion

We collected data on cannabis use and attitudes in over 300 people with IBD across New Zealand. We gained insights into their usual practices and challenges and the reasons for their behaviours, as well as self-reported quality of life and clinical implications. Overall, people reported that using cannabis improved their IBD symptoms such as abdominal pain and cramping, nausea and vomiting and loss of appetite. Along with the effect on the specific symptoms, many respondents felt better able to cope with their diagnosis, an important and perhaps under-acknowledged aspect of living with a chronic condition.

In our survey, the IBD community reported a higher rate of having ever used cannabis (51%) than the general population in 2012/2013 (42%).⁷ Among our survey respondents who had ever used cannabis, 41% reported they used it to reduce their IBD symptoms, and 74% reported that it improved their quality of life to some degree. This is consistent with existing New Zealand data that showed that 42% of those who used cannabis did so for medicinal purposes.⁷ For abdominal pain and cramps, the symptom for which there is perhaps the most clear explanation for an effect of cannabis, 96% of users considered cannabis either “very effective” or “moderately effective” for relief.

Recent Cochrane reviews have found insufficient evidence that cannabis and cannabinoids are either efficacious or safe for treating UC or CD.^22,23 Although there is an absence of clear evidence from randomised controlled trials (RCTs) to say whether cannabis therapy is safe or effective, our observational study provides useful background for prescribers on patients’ experiences and views. In the absence of sufficient RCT data, it is premature to say how our results might relate to the future legislative framework for medicinal cannabis use in New Zealand. At the moment, there is not enough evidence to comment, and there is a need for RCTs to assess efficacy and adverse effects.

To our knowledge, this is the first study of its kind in New Zealand. This is timely given the upcoming 2020 referendum on legalising cannabis for personal use in New Zealand, and this study offers a step towards further study. Our findings also provide information for prescribers on patients’ current usage of cannabis products and their experiences in relation to their disease and symptoms. It cannot, however, comment on the safety or efficacy of cannabis in this population.

Strengths of this study included a good number of responses, with 334 eligible responses over the 12 days the survey was open. Another strength was the participation from respondents around New Zealand, not just the SDHB. However, the likelihood of people responding may have been biased by what they perceived the benefits of cannabis products to be. For example, people who support cannabis legalisation and have ever used cannabis may have been more motivated to take part than those who had never used cannabis.

One limitation was the self-selection aspect in the study design, although this was important for recruitment of the participants. As discussed above, because the link for the survey was open, it was shared to a New Zealand medicinal cannabis awareness Facebook group, and it may have also been shared elsewhere, outside our original recruitment venues. Although there was no evidence of any difference with regard to their use of cannabis, perceived effect of cannabis on IBD symptoms or quality of life, some degree of bias may have been introduced to our data. The likely impact of this would be to overestimate the perceived benefits of cannabis use.

Another limitation of this study relates to cannabis itself. As with other studies looking at cannabis use, it is difficult to accurately measure dose and effect, as “botanical cannabis” preparations contain varying strengths of active ingredients. Furthermore, different methods of use may produce slightly different effects. This study is also limited by the demographics of those who participated, skewing our results towards the experiences of this group.

The legal and political context surrounding cannabis use may have influenced the response rate to this survey. While care was taken to ensure anonymity of participants, some potential participants may have been dissuaded from completing the survey due to concerns about being asked about their use of an illegal substance.

Conclusion

This study suggests that a higher proportion of those with IBD have used cannabis than the general public, and that patients report that cannabis is helpful for relieving a number of IBD symptoms, in particular abdominal pain and cramps, decreased appetite and nausea and vomiting. This is in keeping with a potential biological mechanism for the relief of these symptoms.^15–18

Further studies with a stronger design (eg, RCTs) would be needed to comment on the efficacy and safety of cannabis in relieving IBD symptoms. In the meantime, with medicinal cannabis being topical in New Zealand currently and a common topic of patient enquiry, it is important that medical practitioners are aware of what cannabinoid products are available within New Zealand and that they can respond to relevant questions asked by their patients.

Addendum, 12 February 2021

This survey was conducted in February 2020 and the 2020 New Zealand cannabis referendum, a non-binding referendum, held on 17 October 2020, prior to this study being accepted for publication.  Legalisation of cannabis use was rejected by a narrow margin with 50.7% of voters opposing legalisation and 48.4% in support. There was a lot of publicity around the topic in the months prior to the referendum.

Appendix

Appendix Figure 1: Details of validation of the sample following sharing outside of target population.

A source of potential bias was the survey link being shared to a New Zealand medicinal cannabis awareness Facebook group three days after the survey went live. The link was removed within 24 hours, when we became aware of it. Due to the anonymous nature of our study, and no time stamps on responses, it was impossible to identify and exclude any responses that might have been sourced from the page that shared our link. The survey did, however, include questions about which District Health Board (DHB) respondents were from and how they heard about the survey (via postal mail, or via CCNZ, or both). Respondents who said they were both from SDHB and had been notified of the study by a written letter were considered likely to have been recruited from the Otago IBD database, and therefore likely to have diagnosed IBD and represent our intended source population. Therefore we decided to keep the survey open for nearly two weeks as originally intended, and then to compare responses from this subset (referred to as SDHB Letter Group) with those from the remainder of the eligible responses (referred to as Remainder of Whole Group) for key questions that would be expected to display differences should there have been significant bias from a cannabis awareness group. This allowed us to assess the validity of analysing the larger dataset comprising all eligible responses to answer our study questions, compared to restricting analysis to the SHDB Letter Group.