This study found that motivations for cannabis consumption by people with endometriosis internationally are comparable to those previously reported in Australia and New Zealand (Armour et al. 2019b, Sinclair et al. 2021b, 2023a). In addition, significant associations were observed for the non-legal therapeutic cohort relating to the negative impact of cannabis-associated stigma, breaking the law, and potentially losing employment or driving licences due to prevailing laws or workplace drug policies, which mirror concerns from previous research in Australia and New Zealand (Sinclair et al. 2023a). Similarly, those seeing medical professionals to obtain their cannabis reported a significant impact relating to cost concerns versus non-legal therapeutic and legal therapeutic access pathways. The impact of the cost of medicinal cannabis products has been previously reported (Lintzeris et al. 2018, Lintzeris et al. 2020, Proudfoot et al. 2024), and may be driving people to utilise cannabis from non-legal sources. Such trends raise concerns about equity, particularly as those utilising non-legal cannabis are also concerned about the potential poor quality and adulteration (e.g. heavy metals, pesticide residues, microbial contamination, non-standardised cannabinoid profile) of the cannabis they are accessing, described in this study and others (Lintzeris et al. 2018, Sinclair et al. 2021b, 2023a). As such, barriers to cannabis usage by people with endometriosis appear relatively universal across various geographical locations and cultural backgrounds, as represented by our diverse sample of respondents.

Respondents’ motivations to try cannabis are interlinked with their subsequent decisions behind continuing to consume cannabis for symptomatic management. Similar to the motivations reported in this study, previous research, both qualitative and quantitative (Mercurio et al. 2019, Sinclair et al. 2021b, 2023a), has highlighted that participants with endometriosis deemed cannabis to be superior to prescription medications, while also having fewer side-effects and improving quality of life. Another common reason for ongoing cannabis consumption included concerns over addiction and dependence on pharmaceutical medications. These concerns are valid given people with endometriosis have higher probabilities of prolonged use of opioids and concomitant use with benzodiazepines (Lamvu et al. 2019), as well as a four-times greater risk of chronic opioid use compared to those without endometriosis (Chiuve et al. 2021). Conversely, cannabis itself (mainly the THC component, as CBD is non-addictive) also has addiction and abuse potential (Panlilio et al. 2015, Zehra et al. 2018, Millar et al. 2021), with cannabis use disorder (CUD) being an underappreciated risk that impacts up to 10% of the population utilising cannabis (Connor et al. 2021). Such risks highlight the importance of open communication with medical professionals, and their ongoing supervision and monitoring. Unfortunately, non-disclosure of cannabis consumption for endometriosis symptom management to health professionals, that our team has previously reported in Australia and New Zealand (Sinclair et al. 2021b), appears to be occurring worldwide. Concerns include potentially clinically important pharmacokinetic and pharmacodynamic interactions between cannabis and pharmaceutical medications, which, while rare (Maccallum & Russo 2018), are an important consideration, particularly with warfarin, clobazam, and drugs that affect the central nervous system (CNS) (Devinsky et al. 2017, Maccallum & Russo 2018, Damkier et al. 2019, Lopera et al. 2022).

There are potential consequences from this lack of discussion or disclosure: i) possible interactions between cannabis and pharmaceutical drugs that patients are taking concurrently (Alsherbiny & Li 2019, Lopera et al. 2022), ii) potentially significant adverse outcomes such as CUD and cannabis hyperemesis syndrome (Sinclair et al. 2023b) that consumers may not be aware of, and iii) patient-initiated reductions in medications such as opioids and benzodiazepines, both commonly prescribed in endometriosis (Lamvu et al. 2019, Chiuve et al. 2021), being undertaken without medical supervision, which is potentially dangerous, especially in the case of benzodiazepines, due to potentially fatal withdrawals (Schweizer & Rickels 1998). In addition, patients undergoing surgery who do not disclose cannabis utilisation to their medical team are risking possibly dangerous interactions with anaesthesia.

Another significant driver for cannabis consumption was that consumers considered it a natural product. The emphasis on ‘naturalness’ may be an indication that people with endometriosis perceive cannabis as a safer option compared to other pharmaceutical treatments. While it cannot be known if the concern towards current or previous pharmaceutical medications is derived from prior experience, respondents were less worried about possible dependence on cannabis, with only 15.9% concerned about this, compared to the 43.9% who were concerned about dependence or addiction with their current or previous pharmaceutical medications. This is similar to trends observed in the wider reproductive health field; women have reported dissatisfaction with hormonal contraceptives because they are deemed ‘unnatural’, thus less safe, than natural options (Le Guen et al. 2021). However, perceived naturalness being inherently healthier and safer is not necessarily the case. While cannabis usage has been linked with decreased side-effects compared to other commonly prescribed analgesics (e.g. opioids) (Boehnke et al. 2016), it is not without its risks (as noted above), and there is little evidence on long-term safety for regular consumers. As such, healthcare professionals need to be aware that some people consuming cannabis may not be aware of potential adverse events and believe this option to be ‘risk free’, and thus need to spend time educating those who consume cannabis on possible risks and side-effects. Another factor in the emphasis on the naturalness of cannabis may also be an effort to de-stigmatise its usage (Morris 2020). Naturalism is often used to downplay stigma associated with cannabis, as framing cannabis as a medicine of ‘nature’ and ‘natural’ works to separate cannabis from chemical substances; with the latter viewed as carrying more side-effects (Morris 2020).

Regarding concerns related to cannabis consumption, stigma is still the greatest concern expressed by respondents continuing to consume cannabis. This finding is a consistent concern across various jurisdictions and clinical indications (Bottorff et al. 2013, Reid 2020, Sinclair et al. 2022, 2023a, Troup et al. 2022, Fehr et al. 2023, Nayak et al. 2023), and in this study, is greater for the population relying on non-legal cannabis for therapeutic purposes. The pervasiveness of stigma represents a critical challenge to overcome if cannabis is to be taken seriously as a medical management option in the wider community, aside from the need for more robust clinical evidence. Stigma is a complex barrier, interwoven into various levels of society, including macro, meso, and micro stigmas, attached to the fact that cannabis as both a medicinal object and recreational object are difficult to separate (Lancaster et al. 2017). A recent UK study highlighted there is a high prevalence of perceived stigma facing patients treated with MC from government officials, medical professionals, the criminal justice system, and society more broadly (Troup et al. 2022). Similar evidence has been reported in the USA (Satterlund et al. 2015, Valencia et al. 2017, Howell et al. 2019), Canada (Ko et al. 2016), and Australia and New Zealand (Siewert et al. 2020, Sinclair et al. 2022, 2023a). While factors such as prevalence, availability, and social tolerance are often cited as reasons for cannabis undergoing a normalisation process in certain countries (Hathaway et al. 2011), other factors such as geographical location, gender, race, culture, religion, socioeconomic status, and social privilege suggest that cannabis-related stigma and discrimination is still largely extant, and that ideas of normalisation may be somewhat premature (Reid 2020, 2021). Certainly, some participants in this study noted extra worries or fears attached to cannabis consumption for certain patient populations, such as people worried about fear of being reprimanded due to having a child; parents who consume cannabis may be further stigmatised and judged more than those without children (Reid 2020). This stigma also seemed to persist across geographical boundaries, even in places such as Canada, where cannabis is federally legal both as a medicine and a recreational substance. To assist in mitigating the impact of stigma, future government health policies, and public health education more broadly, should take a balanced and proactive stance to assist in reducing stigma associated with MC (Clobes et al. 2022).

Respondents reported consuming both legal (medical or social/recreational) and illicit cannabis products. An interesting finding was that in Canada, a country that has federally legalised both social/adult use and medicinal cannabis programmes, the predominant cannabis access pathway for managing their endometriosis symptoms was via legal social/adult use dispensaries, ostensibly without direct medical supervision. The prevalence of obtaining cannabis from social/adult use dispensaries for therapeutic purposes may be due to avoidance of additional incurred medical costs of seeing their doctor, and the convenience of using a local dispensary. This raises an important point for discussion, which is what ‘medicinal cannabis’ is and what it is not. In North America, a doctor typically provides legal authorisation (e.g. a medical cannabis card) for a patient to access and utilise cannabis, but does not specify the specific products to be utilised, with this information typically coming from dispensary staff; conversely, in countries such as New Zealand and Australia, the access to and prescription of specific medicinal cannabis products is entirely overseen by doctors, with pharmacist dispensation of product. As such, it does raise concerns as to whether cannabis dispensary staff are adequately equipped to address the complex symptomatology of endometriosis, and whether this pathway may reduce disclosure to, and oversight by, medical doctors. Lack of communication about cannabis consumption for therapeutic reasons should not be considered as solely the responsibility of the patient. Doctors and other healthcare providers have reported a lack of knowledge and a dearth of clinical evidence associated with cannabis being responsible, in part, for hindering the discussion, and subsequent prescription, of MC (Karanges et al. 2018, Gardiner et al. 2019, Oldfield et al. 2020, Dobson et al. 2024). Similarly, King et al. (2024) also found this to be the case in the US, with this present study adding to the evidence that people anticipate stigma from healthcare providers, thus leading to non-disclosure of cannabis consumption. The issue of stigma in the doctor-patient interaction may be even more relevant for those with endometriosis, given that people with endometriosis often report inadequate treatment by healthcare professionals (Evans et al. 2022, Sirohi et al. 2023). As standard endometriosis care is often perceived as inadequate, this may be exacerbated by treating doctors who know little about MC, leading to further stigmatisation and inadequate care. As more people with endometriosis are seeking and using cannabis as a viable symptom management option, healthcare professionals should educate themselves on MC and its potential role in endometriosis treatment. Despite our data being collected in 2021, stigma still unfortunately seems to remain a significant barrier for cannabis consumption in a variety of age groups (Dahlke et al. 2024, King et al. 2024), noting that there is often a lag between societal change and the published literature.

There are several limitations to this study which are important to outline. Recall bias (Pannucci & Wilkins 2010) and non-response bias (Berg 2005) can influence responses and skew the sample towards those that are either more severe in their symptom expression or more favourable towards cannabis, are respective limitations. So too is sampling bias (Benedict et al. 2019) due to the survey being advertised through the use of social media to endometriosis advocacy and support groups, potentially skewing results to include people more negatively impacted by their endometriosis compared to the general population. It also stands to reason that those having strong positive or negative responses to MC consumption may be more likely to spend time completing the survey, and therefore it is likely that the responses may be skewed. Notwithstanding, data from this paper is consistent with previous studies of similar scope and design (Armour et al. 2019a, 2021, Sinclair et al. 2019). While international in scope, limited participation was noted compared to our team’s previous study (Armour et al. 2022), with lower than projected responses. This in part could be due to the survey running in the midst of the global COVID-19 pandemic; however, it may also be a result of survey (response) fatigue (De Koning et al. 2021, Brown et al. 2024), as this method of inquiry (i.e. surveys) was all that was available to many research teams during this time, and results may therefore not be generalisable to the wider endometriosis population. The sample was also Western-centric, which may influence the barriers described by respondents compared with other geographic locations. This data was collected in 2021, and cannabis regulations may have changed for certain countries since this time (e.g. Germany legalised medicinal cannabis in 2017, but legalised recreational cannabis in 2024). Given the majority of our respondents were from Western-centric countries that had state-specific or federally legal medicinal cannabis programmes before 2021 (i.e. USA, Canada, Australia, UK, Ireland, New Zealand), these changes are unlikely to materially impact our findings.