Grant: Project Grant

One in five Canadians lives with chronic pain, an invisible but debilitating, distressing, and costly condition that is complex and difficult to treat. Meanwhile, from January 2016 to June 2019, 13,900 opioid-related deaths were recorded in Canada, with contamination of the illicit drug supply a major driver of overdose mortality. People who inject drugs (PWID) are disproportionately affected by both epidemics. Chronic pain is estimated to be 1.5 to 3.0 times more common among PWID compared with the general population, and these individuals may face particular difficulties obtaining adequate pain treatment. There is concern that some might turn to illicit substances (particularly opioids) to manage their pain, inadvertently exposing them to a greater risk of adverse events such as overdose. Nonetheless, little data exists to describe the effects of chronic pain on substance use and related harms in this population. Building on our current work, this study aims to build knowledge of the relationships between chronic pain, substance use, and the risk of adverse events (fatal and non-fatal overdose, hepatitis C infection) and to investigate how use of health services and mental health status influence outcomes. To achieve this, we will continue to follow a cohort of active PWID in Montreal at 3-month intervals, collecting data via questionnaires and blood samples at each visit. Data will be analysed by statistical techniques examining the relations between pain, substance use, and adverse events over time. We will also conduct in-depth interviews with a subset of the cohort (individuals who have chronic pain and have recently experienced an adverse event) to explore their perceptions of living with chronic pain, its relationship to their use of substances and their experiences with health services, and how this has evolved since the event.