UK Medical Cannabis Registry: A two-year case series of clinical outcomes in depression

BACKGROUND: Whilst preclinical evidence details the effects of cannabinoids on mood regulation, there is a paucity of clinical evidence on the use of cannabis-based medicinal products (CBMPs) in individuals with depression. This study aims to evaluate longitudinal changes in patient-reported outcome measures (PROMs) and the incidence of adverse events over 24 months in patients treated with CBMPs for depression. METHODS: Patient data from the UK Medical Cannabis Registry were used for analysis. PROMs, including the Patient Health Questionnaire-9 (PHQ-9), Generalised Anxiety Disorder-7 (GAD-7), Single-Item Sleep Quality Scale (SQS), EuroQol 5-Dimension 5-Level (EQ-5D-5L), and Patient Global Impression of Change (PGIC), were measured at baseline, 1, 3, 6, 12, 18, and 24 months. Adverse events (AEs) were also recorded. P < 0.050 was considered statistically significant. RESULTS: Of the 34,563 patients in the UK Medical Cannabis Registry on January 6th 2025, 698 (2.02 %) patients were included in the analysis. Improvements were observed across the PHQ-9. GAD-7, SQS, and EQ-5D-5L index value at all time points compared to baseline (p < 0.001). At baseline, half of the patients reported severe anxiety (GAD-7 ≥ 15: 50.86 %, n = 355), which was correlated with depression severity (PHQ-9; r = 0.67, p < 0.001). Sixty-three patients (9.03 %) reported at least one AE during treatment, of which 87.26 % (n = 411) were mild or moderate. DISCUSSION: Initiation of CBMPs was associated with statistically and clinically significant improvements in depression, anxiety, sleep quality, and health-related quality of life among patients. Improvements were most prominent in the first 3 months. Limitations of the study mean that no causal relationship can be ascertained. CONCLUSION: The positive findings from this and other observational data support future evaluation of CBMPs for the treatment of depression to establish their efficacy.