Cannabis-based medicinal products (CBMPs) have been identified as novel therapeutics for generalised anxiety disorder (GAD) based on pre-clinical models; however, there is a paucity of high-quality evidence on their effectiveness and safety.

This study aimed to evaluate the clinical outcomes of patients with GAD treated with dried flower, oil-based preparations, or a combination of both CBMPs.

A prospective cohort study of patients with GAD (n = 302) enrolled in the UK Medical Cannabis Registry prescribed oil or flower-based CBMPs was performed. Primary outcomes were changes in generalised anxiety disorder-7 (GAD-7) questionnaires at 1, 3, and 6 months compared to baseline. Secondary outcomes were single-item sleep quality scale (SQS) and health-related quality of life index (EQ-5D-5L) questionnaires at the same time points. These changes were assessed by paired t-tests. Adverse events were assessed in line with CTCAE (Common Terminology Criteria for Adverse Events) v4.0.

Improvements in anxiety, sleep quality and quality of life were observed at each time point (p < 0.001). Patients receiving CBMPs had improvements in GAD-7 at all time points (1 month: difference −5.3 (95% CI −4.6 to −6.1), 3 months: difference −5.5 (95% CI −4.7 to −6.4), 6 months: difference −4.5 (95% CI −3.2 to −5.7)). Thirty-nine participants (12.9%) reported 269 adverse events in the follow-up period.

Prescription of CBMPs in those with GAD is associated with clinically significant improvements in anxiety with an acceptable safety profile in a real-world setting. Randomised trials are required as a next step to investigate the efficacy of CBMPs.