(219) What motivates patients with chronic musculoskeletal pain to use medical cannabis as a treatment strategy? Results from a questionnaire study.

Background: Chronic musculoskeletal (MSK) pain has multiple causes and affects many people in many countries. Current pharmacological options do not always provide optimal relief from chronic MSK pain. Although some pharmacological properties of cannabis have been known for millennia, evidence on its efficacy and safety in treating pain remains conflicting. Moreover, knowledge about patient perceptions and motivations regarding this therapeutic strategy is very limited. This constitutes an important knowledge gap given the recent legalization of cannabis in several jurisdictions.

Objectives: This study used a questionnaire based on the Theory of Planned Behavior (TPB) to explore and quantify what motivates patients to start or continue use of cannabis for the treatment of chronic MSK pain.

Methods: A qualitative step of this research, performed priorly, consisted of semi-structured interviews with patients, performed in 2020, in Quebec, Canada, and based on the TPB. The results from this step allowed to develop a questionnaire to quantify which TPB elements, together with pain and other patient characteristics, relate to the intention to start or continue use of cannabis for the treatment of chronic MSK pain. The questionnaire was validated and also comprised priorly validated or published scales and questions on pain and other characteristics. We applied a published strategy for TPB based questionnaires on health-related behaviors. The questionnaire was placed online for completion across Canada in both French and English, between October 2021 and May 2022. Questionnaire results were analyzed using descriptive statistics and path analyses regarding the TPB.

Results: Among 226 persons who self-selected to complete the questionnaire, 160 had answered all TPB related questions and could be included in final analyses. The resulting adjusted and reduced TPB based model explained 51% (R square) of the intention to start or continue use of cannabis to treat chronic MSK pain, through exogenous factors related to current pain, perceived pain reduction in the last 24 hour, and prior cannabis use, and, to a larger extent, through normative, control and behavior beliefs. These factors and beliefs affected subjective norms, perceived ability, and attitude, which in turn affected the behavioral intention.

Conclusions: The results of this study are relevant for decision making regarding the use of cannabis to treat chronic MSK pain between patients and their health care providers. The results on patients' beliefs, norms and attitudes informed the development of a decision box, a tool to improve shared decision-making, which is available online in French and English.