title: Effects of methamphetamine administration on information gathering during probabilistic reasoning in healthy humans.
abstract: Jumping to conclusions (JTC) during probabilistic reasoning is a cognitive bias repeatedly demonstrated in people with schizophrenia and shown to be associated with delusions. Little is known about the neurochemical basis of probabilistic reasoning. We tested the hypothesis that catecholamines influence data gathering and probabilistic reasoning by administering intravenous methamphetamine, which is known to cause synaptic release of the catecholamines noradrenaline and dopamine, to healthy humans whilst they undertook a probabilistic inference task. Our study used a randomised, double-blind, cross-over design. Seventeen healthy volunteers on three visits were administered either placebo or methamphetamine or methamphetamine preceded by amisulpride. In all three conditions participants performed the "beads" task in which participants decide how much information to gather before making a probabilistic inference, and which measures the cognitive bias towards jumping to conclusions. Psychotic symptoms triggered by methamphetamine were assessed using Comprehensive Assessment of At-Risk Mental States (CAARMS). Methamphetamine induced mild psychotic symptoms, but there was no effect of drug administration on the number of draws to decision (DTD) on the beads task. DTD was a stable trait that was highly correlated within subjects across visits (intra-class correlation coefficients of 0.86 and 0.91 on two versions of the task). The less information was sampled in the placebo condition, the more psychotic-like symptoms the person had after the methamphetamine plus amisulpride condition (p = 0.028). Our results suggest that information gathering during probabilistic reasoning is a stable trait, not easily modified by dopaminergic or noradrenergic modulation.
authors: Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom.
authors: Anna O
authors: AO
authors: Ermakova
authors: Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, United Kingdom.
authors: Pranathi
authors: P
authors: Ramachandra
authors: Department of Psychiatry, Yale University, New Haven, Connecticut, United States of America.
authors: Philip R
authors: PR
authors: Corlett
authors: Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, United Kingdom; Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom.
authors: Paul C
authors: PC
authors: Fletcher
authors: Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, United Kingdom; Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom.
authors: Graham K
authors: GK
authors: Murray
mesh_terms: D000328:Adult; D003657:Decision Making / Q000187:drug effects*; D003702:Delusions / Q000503:physiopathology; D004298:Dopamine / Q000378:metabolism; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008694:Methamphetamine / Q000008:administration & dosage*; D009638:Norepinephrine / Q000378:metabolism; D012559:Schizophrenia / Q000188:drug therapy / Q000503:physiopathology*; D013850:Thinking / Q000187:drug effects*; D055815:Young Adult
chemical_list: D008694:Methamphetamine; D004298:Dopamine; D009638:Norepinephrine