WHY IT MATTERS: Arizona adults who are about to start using cannabis for a medical condition have a time-sensitive opportunity to contribute to national research that could directly shape how physicians recommend and dose cannabis for patients like them. CLINICAL OVERVIEW: Observational research on medical cannabis is essential for building the real-world evidence base that controlled trials alone cannot provide, particularly given the diversity of conditions, products, and consumption patterns patients bring to clinical settings. Recruiting participants at the point of initiation allows researchers to capture baseline data and track outcomes longitudinally, which strengthens the quality of findings compared to studies that enroll patients already well into their cannabis use.