The impact of cannabidiol placebo on responses to an acute stressor: A replication and proof of concept study

Background: Our group has previously reported that cannabidiol (CBD) expectancy alone blunts markers of stress, particularly during anticipation, but it is not clear the extent to which such findings were specific to the methods utilized.

Aims: To examine CBD-related placebo effects on stress reactivity and anticipation and to validate a protocol to be used in a neuroimaging study.

Methods: Forty-eight healthy adults (24 female) were randomly assigned to be informed that they ingested a CBD-containing oil or a CBD-free oil despite receiving the same oil (CBD-free). Following oil administration, participants engaged in a laboratory stressor and were then incorrectly informed that they would engage in a second more difficult task following a waiting period. Subjective state (sedation, energy, stress, anxiety) and heart rate were assessed at baseline, post-oil administration, immediately following the first stressor, and while anticipating the second stressor.

Results: Subjective stress and anxiety were significantly elevated immediately following the stressor (p-values < 0.001). CBD expectancy was associated with increased subjective sedation (p < 0.01) and tended to be associated with blunted subjective stress (p = 0.053). Post hoc within-condition pairwise compassions suggested a return to pre-stressor levels during the anticipation period in the CBD condition for subjective stress and anxiety (p = 0.784, 0.845), but not the CBD-free condition (p = 0.025, 0.045).

Conclusion: Results replicate and extend previous findings that CBD expectancy alone can impact stress- and anxiety-relevant responses in the laboratory context.