title: Depressive patients are more impulsive and inconsistent in intertemporal choice behavior for monetary gain and loss than healthy subjects--an analysis based on Tsallis' statistics.
abstract: OBJECTIVE
  Depression has been associated with impaired neural processing of reward and punishment. However, to date, little is known regarding the relationship between depression and intertemporal choice (delay discounting) for gain and loss. This examination is potentially important for advances in neuroeconomics of intertemporal choice, because depression is associated with reduced serotonergic activities in the brain.
  
  
  METHODS
  We compared impulsivity and inconsistency in intertemporal choice for monetary gain and loss between depressive patients and healthy control subjects.
  
  
  METHODS
  We conducted delay discounting tasks for gain and loss in depressed and healthy control subjects. We then quantified impulsivity and inconsistency in the delay discounting with parameters in the q-exponential discount function based on Tsallis' statistics.
  
  
  RESULTS
  We observed that depressive patients were more impulsive and time-inconsistent in intertemporal choice action for gain and loss, in comparison to healthy controls.
  
  
  RESULTS
  Depressed patients were more irrational in temporal discounting.
  
  
  CONCLUSIONS
  The usefulness of the q-exponential discount function for assessing the impaired decision-making by depressive patients was demonstrated. Furthermore, biophysical mechanisms underlying the altered intertemporal choice by depressive patients are discussed in relation to impaired serotonergic neural systems.
authors.affiliation: Unit of Cognitive and Behavioral Sciences, Department of Life Sciences, School of Arts and Sciences, The University of Tokyo, Komaba, Tokyo, 153-8902, Japan. taikitakahashi@gmail.com
authors.forename: Taiki
authors.initials: T
authors.lastname: Takahashi
authors.forename: Hidemi
authors.initials: H
authors.lastname: Oono
authors.forename: Takeshi
authors.initials: T
authors.lastname: Inoue
authors.forename: Shuken
authors.initials: S
authors.lastname: Boku
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kako
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kitaichi
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kusumi
authors.forename: Takuya
authors.initials: T
authors.lastname: Masui
authors.forename: Shidn
authors.initials: S
authors.lastname: Nakagawa
authors.forename: Katsuji
authors.initials: K
authors.lastname: Suzuki
authors.forename: Teruaki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Koyama
authors.forename: Mark H B
authors.initials: MH
authors.lastname: Radford
mesh_terms: D000328:Adult; D000368:Aged; D002755:Choice Behavior / Q000502:physiology*; D003627:Data Interpretation, Statistical; D003866:Depressive Disorder / Q000523:psychology*; D004467:Economics; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012201:Reward; D012701:Serotonin / Q000097:blood; D011795:Surveys and Questionnaires
chemical_list: D012701:Serotonin