title: Dopamine effects on evidence gathering and integration.
abstract: BACKGROUND
  Disturbances in evidence gathering and disconfirmatory evidence integration have been associated with the presence of or propensity for delusions. Previous evidence suggests that these 2 types of reasoning bias might be differentially affected by antipsychotic medication. We aimed to investigate the effects of a dopaminergic agonist (L-dopa) and a dopaminergic antagonist (haloperidol) on evidence gathering and disconfirmatory evidence integration after single-dose administration in healthy individuals.
  
  
  METHODS
  The study used a randomized, double-blind, placebo-controlled, 3-way crossover design. Participants were healthy individuals aged 18-40 years. We administered a new data-gathering task designed to increase sensitivity to change compared with traditional tasks. The Bias Against Disconfirmatory Evidence (BADE) task was used as a measure of disconfirmatory evidence integration.
  
  
  RESULTS
  We included 30 individuals in our study. In the data-gathering task, dopaminergic modulation had no significant effect on the amount of evidence gathered before reaching a decision. In contrast, the ability of participants to integrate disconfirmatory evidence showed a significant linear dopaminergic modulation pattern (highest with haloperidol, intermediate with placebo, lowest with L-dopa), with the difference between haloperidol and L-dopa marginally reaching significance.
  
  
  CONCLUSIONS
  Although the doses used for haloperidol and L-dopa were similar to those used in previous studies, drug plasma level measurements would have added to the validity of findings.
  
  
  CONCLUSIONS
  Evidence gathering and disconfirmatory evidence integration might be differentially influenced by dopaminergic agents. Our findings are in support of a dual-disturbance account of delusions and provide a plausible neurobiological basis for the use of interventions targeted at improving reasoning biases as an adjunctive treatment in patients with psychotic disorders.
authors.affiliation: From the Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Andreou
authors.affiliation: From the Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Brooke C
authors.initials: BC
authors.lastname: Schneider
authors.affiliation: From the Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Vivien
authors.initials: V
authors.lastname: Braun
authors.affiliation: From the Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Kolbeck
authors.affiliation: From the Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Gallinat
authors.affiliation: From the Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Moritz
mesh_terms: D000293:Adolescent; D000328:Adult; D018592:Cross-Over Studies; D003657:Decision Making / Q000187:drug effects* / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism*; D015259:Dopamine Agents / Q000494:pharmacology*; D004311:Double-Blind Method; D005260:Female; D006220:Haloperidol / Q000494:pharmacology; D006801:Humans; D007980:Levodopa / Q000494:pharmacology; D016014:Linear Models; D008297:Male; D009483:Neuropsychological Tests; D011340:Problem Solving / Q000187:drug effects* / Q000502:physiology*; D055815:Young Adult
chemical_list: D015259:Dopamine Agents; D007980:Levodopa; D006220:Haloperidol; D004298:Dopamine