Loading...
Individual and combined effects of acute delta-9-tetrahydrocannabinol and cannabidiol on psychotomimetic symptoms and memory function
Celia Morgan Tom P. Freeman Chandni Hindocha Grainne Schafer Chelsea Gardner H. Valerie Curran
Celia Morgan
Tom P. Freeman
Chandni Hindocha
Grainne Schafer
Chelsea Gardner
H. Valerie Curran
Abstract
The main active ingredient in cannabis, delta-9-tetrahydrocannabinol (THC), can acutely induce psychotic symptoms and impair episodic and working memory. Another major constituent, cannabidiol (CBD), may attenuate these effects. This study aimed to determine the effects of THC and CBD, both alone and in combination on psychotic symptoms and memory function. A randomised, double-blind crossover design compared the effects of (i) placebo, (ii) THC 8 mg, (iii) CBD 16 mg and (iv) THC 8 mg + CBD 16 mg administered by inhalation through a vaporiser. Using an experimental medicine approach to predict treatment sensitivity, we selected 48 cannabis users from the community on the basis of (1) schizotypal personality questionnaire scores (low, high) and (2) frequency of cannabis use (light, heavy). The Brief Psychiatric Rating Scale (BPRS), Psychotomimetic States Inventory (PSI), immediate and delayed prose recall (episodic memory), 1- and 2-back (working memory) were assessed on each day. Results indicated that THC increased overall scores on the PSI, negative symptoms on BPRS, and robustly impaired episodic and working memory. Co-administration of CBD did not attenuate these effects. CBD alone reduced PSI scores in light users only. At a ratio of 2:1, CBD does not attenuate the acute psychotic and memory impairing effects of vaporised THC. Frequent cannabis users may show a blunted anti- psychotic response to CBD, which is of concern due to the high rates of cannabis use disorders in patients with schizophrenia.
Keywords
addiction, clinical pharmacology, human behaviour
Date
2018
Type
Journal article
Journal
Translational Psychiatry (online)
Book
Volume
8
Issue
1
Page Range
1-10
Article Number
ACU Department
School of Behavioural and Health Sciences
Faculty of Health Sciences
Faculty of Health Sciences
Relation URI
Source URL
Event URL
Open Access Status
Published as ‘gold’ (paid) open access
License
CC BY 4.0
File Access
Open