Cannabidiol does not attenuate acute delta‐9‐tetrahydrocannabinol‐induced attentional bias in healthy volunteers: A randomised, double‐blind, cross‐over study

Abstract

AbstractAimsTo test how attentional bias and explicit liking are influenced by delta‐9‐tetrahydrocannabinol (THC) and whether these effects are moderated by cannabidiol (CBD).DesignDouble‐blind, randomised, within‐subjects cross‐over study.SettingNIHR Wellcome Trust Clinical Research Facility at King's College Hospital, London, United Kingdom.Participants/CasesForty‐six infrequent cannabis users (cannabis use <1 per week).Intervention(s)Across four sessions, participants inhaled vaporised cannabis containing 10 mg of THC and either 0 mg (0:1 CBD:THC), 10 mg (1:1), 20 mg (2:1) or 30 mg (3:1) of CBD, administered in a randomised order and counter‐balanced across participants (a total of 24 order groups).MeasurementsParticipants completed two tasks: (1) Attentional Bias (AB), comparing reaction times toward visual probes presented behind 28 target stimuli (cannabis/food) compared with probes behind corresponding non‐target (neutral) stimuli. Participants responding more quickly to probes behind target than non‐target stimuli would indicate greater attentional bias to cannabis/food; (2) Picture Rating (PR), where all AB stimuli were rated on a 7‐point pleasantness scale, measuring explicit liking.FindingsDuring the AB task, participants were more biased toward cannabis stimuli in the 0:1 condition compared with baseline (mean difference = 12.2, 95% confidence intervals [CIs] = 1.20–23.3, d = 0.41, P = 0.03). No other significant AB or PR differences were found between cannabis and food stimuli between baseline and 0:1 condition (P > 0.05). No significant CBD effect was found on AB or PR task performance at any dose (P > 0.05). There was additionally no cumulative effect of THC exposure on AB or PR outcomes (P > 0.05).ConclusionsA double‐blind, randomised, cross‐over study among infrequent cannabis users found that inhaled delta‐9‐tetrahydrocannabinol increased attentional bias toward cannabis in the absence of explicit liking, a marker of liability toward cannabis use disorder. At the concentrations normally found in legal and illegal cannabis, cannabidiol had no influence on this effect.