title: The effects of low doses of delta-9 tetrahydrocannabinol on reinforcement processing in the risky decision-making of young healthy adults.
abstract: Research suggests that risky decision-making is sensitive to neuromodulatory influences acting upon corticolimbic circuitry. However, while other evidence attests to effects of delta-9 tetrahydrocannabinol (THC) on the activity of reward pathways, relatively little is known about the possible involvement of cannabinoid activity in risky choice. In this experiment, we examined the effects of a single sublingual 5 mg dose of THC on a test of risky decision-making (requiring choices between simultaneously presented gambles differing in their magnitude of gains, magnitude of losses and the probability with which these outcomes were delivered). Tests of non-normative decision-making involving risk-aversion when deciding between gains and risk-seeking choices when deciding between losses were also included. In all, 15 healthy adults were administered 5 mg THC and placebo in a double-blind, placebo-controlled, within-subject, cross-over design. THC had three principal effects relative to placebo: (i) THC reduced choice of gambles with variable gains and losses, but increased choice of gambles with zero-expected value; (ii) THC reduced participants' attention towards losses when the probability of winning was low (and the probability of losing was high); and (iii) THC speeded participants' responses to gambles with large compared to small potential gains. These results suggest that THC mediates specific motivational processes and the processing of reinforcement cues during risky choice, perhaps reflecting altered CB1 receptor or catecholamine activity within corticolimbic pathways.
authors.affiliation: Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK. robert.rogers@psych.ox.ac.uk
authors.forename: Robert D
authors.initials: RD
authors.lastname: Rogers
authors.forename: Judi
authors.initials: J
authors.lastname: Wakeley
authors.forename: Phillip J
authors.initials: PJ
authors.lastname: Robson
authors.forename: Zubin
authors.initials: Z
authors.lastname: Bhagwagar
authors.forename: Petra
authors.initials: P
authors.lastname: Makela
mesh_terms: D000328:Adult; D000367:Age Factors; D001288:Attention / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D002395:Catecholamines / Q000378:metabolism; D003071:Cognition / Q000187:drug effects* / Q000502:physiology; D003072:Cognition Disorders / Q000139:chemically induced* / Q000503:physiopathology / Q000523:psychology; D018592:Cross-Over Studies; D003657:Decision Making / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D013759:Dronabinol / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D009434:Neural Pathways / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D009483:Neuropsychological Tests; D010919:Placebos; D011619:Psychotropic Drugs / Q000494:pharmacology; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D043884:Receptor, Cannabinoid, CB1 / Q000187:drug effects / Q000378:metabolism; D012054:Reinforcement, Psychology; D012309:Risk-Taking
chemical_list: D002395:Catecholamines; D010919:Placebos; D011619:Psychotropic Drugs; D043884:Receptor, Cannabinoid, CB1; D013759:Dronabinol