In contrast to previous studies, there was no evidence of any benefits of cannabidiol on anxiety or persecutory ideation in healthy volunteers with high trait paranoia. However, a larger sample will be required for a definitive study.

Immersion in the virtual-reality session elicited anxiety as indexed by the Beck’s anxiety inventory ( p <0.005), and increased cortisol concentration ( p =0.05), heart rate ( p <0.05) and systolic blood pressure ( p <0.05). However, cannabidiol had no impact upon any of these effects, except for a strong trend to increase anxiety ( p =0.09). Cannabidiol had no effect on persecutory ideation as assayed by the Community Assessment of Psychic Experiences questionnaire or the State Social Paranoia Scale.

Immersion in a controlled 3D virtual-reality scenario was used to assay persecutory ideation and anxiety in a sample of non-clinical volunteers ( n =32) pre-selected for high paranoid traits. Participants were randomised to receive oral cannabidiol (600 mg) or placebo 130 min prior to entering virtual-reality. Well-validated rating scales were used to assay persecutory thinking and anxiety. Salivary cortisol concentration, heart rate and blood pressure were measured over the course of the experimental session.

Previous studies have suggested that cannabidiol has anxiolytic and antipsychotic properties, raising hopes that cannabidiol will translate to the psychiatric clinic. Cannabidiol may be particularly useful for anxiety and paranoia in those at-risk of major mental illness.

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