title: Intolerance of uncertainty mediates reduced reward anticipation in major depressive disorder.
abstract: BACKGROUND
  Reduced reward sensitivity has long been considered a fundamental deficit of major depressive disorder (MDD). One way this deficit has been measured is by an asymmetry in electroencephalogram (EEG) activity between left and right frontal brain regions. MDD has been associated with a reduced frontal EEG asymmetry (i.e., decreased left relative to right) while anticipating reward. However, the mechanism (or mediator) of this association is unclear. The present study examined whether intolerance of uncertainty (IU) mediated the association between depression and reduced reward anticipation.
  
  
  METHODS
  Data were obtained from a prior study reporting reduced frontal EEG asymmetry while anticipating reward in early-onset MDD. Participants included 156 individuals with early-onset MDD-only, panic disorder-only, both (comorbids), or controls. Frontal EEG asymmetry was recorded during an uncertain reward anticipation task. Participants completed a self-report measure of IU.
  
  
  RESULTS
  All three psychopathology groups reported greater IU relative to controls. Across all participants, greater IU was associated with a reduced frontal EEG asymmetry. Furthermore, IU mediated the relationship between MDD and frontal EEG asymmetry and results remained significant after controlling for neuroticism, suggesting effects were not due to broad negative affectivity.
  
  
  CONCLUSIONS
  MDD participants were limited to those with early-onset depression. Measures were collected cross-sectionally, precluding causal relationships.
  
  
  CONCLUSIONS
  IU mediated the relationship between MDD and reduced reward anticipation, independent of neuroticism. Explanations are provided regarding how IU may contribute to reduced reward anticipation in depression. Overall, IU appears to be an important mechanism for the association between depression and reduced reward anticipation.
authors.affiliation: Stony Brook University, Department of Psychology, Stony Brook, NY 11794, United States. Electronic address: bradynelson103@gmail.com.
authors.forename: Brady D
authors.initials: BD
authors.lastname: Nelson
authors.affiliation: University of Illinois-Chicago, Department of Psychology, 1007 W. Harrison St. (M/C 285), Chicago, IL 60607, United States.
authors.forename: Stewart A
authors.initials: SA
authors.lastname: Shankman
authors.affiliation: Stony Brook University, Department of Psychology, Stony Brook, NY 11794, United States.
authors.forename: Greg H
authors.initials: GH
authors.lastname: Proudfit
mesh_terms: D000328:Adult; D017668:Age of Onset; D016022:Case-Control Studies; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000453:epidemiology / Q000503:physiopathology* / Q000523:psychology*; D004569:Electroencephalography; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D006801:Humans; D008297:Male; D016584:Panic Disorder / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology; D012201:Reward; D035501:Uncertainty; D055815:Young Adult
keywords: Anticipation; Depression; Electroencephalography; Intolerance of uncertainty; Reward