ABSTRACT Background Cannabis-based medicinal products (CBMPs) are a potential treatment for post-traumatic stress disorder (PTSD), but their long-term efficacy and safety need further investigation. This study assessed the changes in health-related quality of life (HRQoL) and adverse events in PTSD patients prescribed CBMPs. Research design and methods This observational cohort study included PTSD patients enrolled on the UK Medical Cannabis Registry for 18 months or longer. Changes in PTSD-specific symptoms (IES-R), anxiety (GAD-7), sleep quality (SQS), and general HRQoL (EQ-5D-5 L) were assessed at 1, 3, 6, 12, and 18 months. Results In 269 patients, significant improvements in PTSD symptoms, anxiety, sleep quality, and HRQoL were observed...