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Synthetic delta-9-tetrahydrocannabinol elicits schizophrenia-like negative symptoms which are distinct from sedation.

Paul D. Morrison, J M Stone

Human psychopharmacology January 2011 DOI: 10.1002/hup.1166 (opens in new tab)

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Characteristics Randomized controlled trial Peer reviewed
Sample size 22
Population Healthy male volunteers
Intervention delta-9-tetrahydrocannabinol (THC)
Dose 2.5 mg
Measures community assessment of psychic experiences scale (CAPE), mood-adjective check-list (UMACL)
Topics Cannabis
Key findings Intravenous THC (2.5 mg) increased self-reported negative symptoms on the CAPE scale compared with baseline, while placebo did not (p < 0.001). The increase was not related to sedation or plasma THC levels, suggesting THC can elicit schizophrenia-like negative symptoms at recreational-use concentrations.

Abstract

It is unknown if cannabis recreates the negative symptoms of schizophrenia. Healthy male volunteers (n = 22) completed two experimental sessions in which they received intravenous (IV) delta-9-tetrahydrocannabinol (THC) 2.5 mg or placebo in a randomised counterbalanced order. Negative symptoms were rated using the self-reported community assessment of psychic experiences scale (CAPE). Sedation was rated using the mood-adjective check-list (UMACL). Plasma concentrations of THC were measured over the course of the study. Data were analysed by non-parametric tests. Participants reported an increase in negative symptoms from baseline under THC but not placebo conditions (p < 0.001). Negative symptoms showed no relationship with self-rated sedation or plasma concentrations of THC. At plasma concentrations resembling recreational use, THC elicited schizophrenia-like negative symptoms which were not merely attributable to sedation. In the community, negative symptoms may be an adverse effect of cannabis use.

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Study Year Design Participants
Cannabidiol inhibits THC-elicited paranoid symptoms and hippocampal-dependent memory impairment Healthy participants 2012 Randomized controlled trial n = 48
Distinct Effects of Δ9-Tetrahydrocannabinol and Cannabidiol on Neural Activation During Emotional Processing Healthy, English-native, right-handed men who had used cannabis 15 times or less in... 2009 Double-blind, randomized, placebo-controlled crossover trial n = 15
Acute Effects of a Single, Oral dose of d9-tetrahydrocannabinol (THC) and Cannabidiol (CBD) Administration in Healthy Volunteers Healthy male subjects 2012 Randomized controlled trial n = 16
Modulation of Mediotemporal and Ventrostriatal Function in Humans by Δ9-Tetrahydrocannabinol Healthy, native English-speaking, right-handed men of white race/ethnicity who had used... 2009 Randomized controlled trial n = 15
Cannabidiol (CBD) content in vaporized cannabis does not prevent tetrahydrocannabinol (THC)-induced impairment of driving and cognition Healthy volunteers with a history of light cannabis use 2019 Randomized, double-blind, within-subjects crossover n = 14

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