Due to changes in cannabis policy, most Americans now have access to an array of retail cannabis products. An estimated 5.5 million Americans are registered with state-regulated medical cannabis programs and the therapeutic use of federally legal hemp (e.g. CBD) products is widespread. Despite most states having legalized medicinal cannabis use, little is known about the characteristics of these patients, the cannabis products they use, or the patient-level health impact of their medicinal cannabis use. Filling these gaps in knowledge remains an urgent public health need. We propose to: 1) design and implement a prospective medicinal cannabis patient registry for longitudinal data collection. We will recruit a nationally representative cohort of patients newly initiating the use of cannabis for therapeutic purposes into a longitudinal observational research registry. We will assess patient demographics, cannabis product use, and a range of health outcomes prior to and repeatedly after initiation of medicinal cannabis use via web-based surveys. A subset of patients will complete intensive data collection via ecological momentary assessment (EMA) and/or provide biospecimens for clinical chemistry testing to determine the impact of medicinal cannabis use on daily functioning and symptom management in addition to potential unseen harms such as liver toxicity; 2) Establish a program of medicinal cannabis product testing based on adverse event reporting and other mentions of injury/harm in the patient registry or via surveillance of other data sources (e.g. poison control data, FDA warnings, online forum posts). Products associated with adverse events or other harms will be targeted for testing related to dose-label accuracy, cannabinoid content, and presence of contaminants; 3) Identify and integrate existing sources of data that can inform the health impacts of medicinal cannabis use. This includes electronic medical record (EMR) databases as well as prior and ongoing research projects of the study team (e.g., Realm of Caring Observational Research Registry); 4) Develop and implement a website that will include annual summary reports of the combined data, an application process for researcher access to de-identified data for the conduct of novel analyses, and an archive of published papers related to the health impacts of medicinal cannabis use. A pilot research program to fund scientists interested in probing the data repository will be established. Our team includes internationally recognized expertise in the comprehensive research methods proposed. The result of this project will be a rich data resource for understanding the health impacts of medicinal cannabis use. Data will include patient-level outcomes across a broad range of therapeutic purposes and include use of a variety of cannabis products. Data will help inform clinical decision making related to initiation of cannabis products, guidance on product, route of administration and dose selection, risks related to adverse events, injury/poisoning risk and abuse liability. Findings will also help local and federal government agencies develop effective policies, programs, and regulatory strategies to mitigate harms associated with the rapidly growing cannabis industry.

The medicinal use of cannabis has been legalized widely without much evaluation of patient-level outcomes to determine the health effects, positive or negative, of this policy change. This project will include the establishment of a national patient research registry, a cannabis product surveillance and testing program, a program of evaluating patient electronic medical records and a data repository to integrate data from other sources with those collected as part of these initiatives. The data collected and made available to researchers and the public will help inform clinical decision-making about the medicinal use of cannabis as well as help steer policy and regulatory decisions in the interest of public and patient health.