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Acute effects of delta-9-tetrahydrocannabinol, cannabidiol and their combination on facial emotion recognition: A randomised, double-blind, placebo-controlled study in cannabis users
Hindocha, Chandni Freeman, Tom P. Schafer, Grainne Gardener, Chelsea Das, Ravi K. Morgan, Celia J. A. Curran, H. Valerie
Hindocha, Chandni
Freeman, Tom P.
Schafer, Grainne
Gardener, Chelsea
Das, Ravi K.
Morgan, Celia J. A.
Curran, H. Valerie
Abstract
Acute administration of the primary psychoactive constituent of cannabis, Δ-9-tetrahydrocannabinol (THC), impairs human facial affect recognition, implicating the endocannabinoid system in emotional processing. Another main constituent of cannabis, cannabidiol (CBD), has seemingly opposite functional effects on the brain. This study aimed to determine the effects of THC and CBD, both alone and in combination on emotional facial affect recognition. 48 volunteers, selected for high and low frequency of cannabis use and schizotypy, were administered, THC (8 mg), CBD (16 mg), THC+CBD (8 mg+16 mg) and placebo, by inhalation, in a 4-way, double-blind, placebo-controlled crossover design. They completed an emotional facial affect recognition task including fearful, angry, happy, sad, surprise and disgust faces varying in intensity from 20% to 100%. A visual analogue scale (VAS) of feeling ‘stoned’ was also completed. In comparison to placebo, CBD improved emotional facial affect recognition at 60% emotional intensity; THC was detrimental to the recognition of ambiguous faces of 40% intensity. The combination of THC+CBD produced no impairment. Relative to placebo, both THC alone and combined THC+CBD equally increased feelings of being ‘stoned’. CBD did not influence feelings of ‘stoned’. No effects of frequency of use or schizotypy were found. In conclusion, CBD improves recognition of emotional facial affect and attenuates the impairment induced by THC. This is the first human study examining the effects of different cannabinoids on emotional processing. It provides preliminary evidence that different pharmacological agents acting upon the endocannabinoid system can both improve and impair recognition of emotional faces.
Keywords
endocannabinoid system, emotional processing, schizotypy, Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD)
Date
2015
Type
Journal article
Journal
European Neuropsychopharmacology
Book
Volume
25
Issue
3
Page Range
325-334
Article Number
ACU Department
Relation URI
Source URL
Event URL
Open Access Status
Open access
License
CC BY 4.0
File Access
Open