Background: Early evidence outside of oncology has suggested that cannabidiol (CBD) may have anxiolytic effects without neuropsychiatric risks. An understanding of oral CBD in patients with cancer-related anxiety is urgently needed.
DESIGN This phase II, double-masked, placebo-controlled, randomized clinical trial was conducted from November 2, 2021, through March 1, 2023. Women aged >18 years old with advanced breast cancer and baseline clinical anxiety were randomized 1:1 to receive oral CBD, 400 mg, vs placebo within 48hours before a scan assessing tumor burden.
MEASURES The primary endpoint was a between-arm comparison of change scores on the afraid subscale of the Visual Analog Mood Scale (VAMS) before and 2-4 hours after study drug ingestion. The VAMS T-scores of >20 indicates a reliable change, and >30 indicates clinical significance. Exploratory outcomes included between-arm comparisons of anxiety levels 2-4 hours after drug ingestion, change scores on other VAMS, and safety.
RESULTS Among the 50 participants, 25 were randomized to placebo (mean [range] age, 57 [37-81] years) and 25 were randomized to the CBD (mean [range] age, 60 [30-79] years). The primary endpoint of VAMS afraid subscale change score, although numerically greater in the CBD arm, was not significantly different between arms (mean [SD]: CBD, −19.1 [15.4]; placebo, −15.0 [10.9]; P = .37). Comparing anxiety levels between arms 2-4 hours after drug ingestion demonstrated significantly lower VAMS afraid in the CBD arm compared to placebo (mean [SD]: CBD, 51.5 [12.8]; placebo, 58.0 [11.6]; P = .02). No grade 3 or 4 toxic effects were reported.
CONCLUSIONS The findings of this RCT show that CBD can was safe and although, the study did not meet its primary endpoint comparing anxiety change scores between study arms, anxiety levels in the CBD arm were significantly lower 2-4 hours after ingestion, suggesting a possible anxiolytic effect.