This study aims to analyze changes in health-related quality of life (HRQoL) and safety in patients with generalized anxiety disorder (GAD) prescribed a homogenous selection of cannabis-based medicinal products (CBMPs). Patients prescribed Adven CBMPs (Curaleaf International, UK) for GAD were identified from the UK Medical Cannabis Registry. Primary outcomes were changes in patient-reported outcome measures (PROMs) from baseline up to 12 months, including GAD-7, Single-Item Sleep Quality Scale (SQS), and EQ-5D-5L. Adverse events were recorded using CTCAE version 4.0. A total of 120 patients were identified for inclusion, of which 38 (31.67%), 52 (43.33%), and 30 (25.00%) were prescribed oils, dried flower, and both formulations of CBMP. Associated improvements in GAD-7, SQS, and EQ-5D-5L at 1, 3, 6, and 12 months were observed compared to baseline (P < 0.010). There were 24 (20.00%) patients who reported 442 (368.33%) adverse events, most of which were mild (n = 184, 41.63%) and moderate (n = 197, 44.57%). This study reports an association between initiation of a homogeneous CBMP therapy and improvements in anxiety severity and HRQoL in individuals with GAD. Moreover, therapy was well-tolerated at 12 months follow-up. Further investigation through randomized controlled trials will ultimately be required to determine causation.