Opioid poisoning is a public health crisis in Canada, with over 20 Canadians dying daily due to opioid-related incidents. Emergency departments (EDs) play a crucial role in addressing this crisis, as more than half of the individuals who die from opioid poisoning visit an ED in the year prior to their death. However, 20% of these patients leave the ED before completing evaluation or treatment, often due to inadequate systems for engaging and treating them effectively.  This study seeks to establish a national registry to harmonize data collection on patients presenting with opioid poisoning and/or dependence in EDs. This includes patients who are diagnosed with opioid use disorder and who present in opioid withdrawal. Its objectives include understanding variation in clinical practices, identifying effective treatments and harm reduction services, and developing a risk stratification tool to predict 60-day mortality. By targeting patients at the highest risk, this tool will guide the allocation of critical resources in a constrained healthcare environment.  Through collaboration with patients with lived/living experience, the study [...]