Illicit cannabis use to self-treat chronic health conditions:a cross-sectional study from the United Kingdom

Background: In 2019, it was estimated that approximately 1.4 million adults in the United Kingdom (UK) purchase illicit cannabis to self-treat chronic physical and mental health conditions. This analysis was conducted following the rescheduling of cannabis-based medicinal products (CBMPs) in the UK, but before the first specialist clinics had started treating patients. <br/>Objective: The aim of this study was to assess the prevalence of illicit cannabis consumption to treat a medically diagnosed condition, following the introduction of specialist clinics who could prescribe legal CBMPs in the UK.<br/>Methods: Adults over the age of 18 in the UK were invited to participate in a cross-sectional survey through YouGov® between 22nd and 29th September 2022. A series of questions were asked about respondents’ medical diagnoses, illicit cannabis use, cost of purchasing illicit cannabis per month, and basic demographics. The responding sample was weighted to generate a sample representative of the adult population of the UK. Modelling of population size was conducted based on an adult (≥ 18 years) population of 53,369,083 according to 2021 national census data.<br/>Results: There were 10,965 respondents to the questionnaire, to which weighting was applied. 5,700 (51.98%) respondents indicated that they were affected by a chronic health condition. The most reported condition was anxiety (n = 1588; 14.48%). Of those suffering with health conditions, 364 (6.38%) purchased illicit cannabis to self-treat health conditions. Based on survey responses, it was modelled that 1,770,627 (95% confidence interval: 1,073,791–2,467,001) individuals consume illicit cannabis for health conditions across the United Kingdom. On multivariable logistic regression, the following were associated with increased likelihood of reporting illicit cannabis use for health reasons: chronic pain, fibromyalgia, post-traumatic stress disorder, multiple sclerosis, other mental health disorders, male gender, younger age, living in London, being unemployed or not working for other reasons, and working part-time (p&lt;0.050).<br/><br/>Conclusions: This study highlights the scale of illicit cannabis use for health reasons in the UK and the potential barriers to accessing legally prescribed CBMPs. This is an important step in developing harm reduction policies to transition these individuals, where appropriate, to CBMPs. Such policies are particularly important considering the potential risks from harmful contaminants of illicit cannabis and self-treating a medical condition without clinical oversight. Moreover, it emphasises the need for further funding of randomised controlled trials and the use of novel methodologies to determine the efficacy of CBMPs and their utility in common chronic conditions.<br/>