title: Cooperation and depressive symptoms.
abstract: BACKGROUND
  Deficits in pro-social cooperation are common in many individuals with mental illnesses such as depression. For decades, researchers have used economic game paradigms to compare cross-cultural cooperative behavior. However, research using economic games to assess cooperative behavior in clinical populations is in the early stages. We hypothesized that individuals with greater depressive symptoms would struggle to maintain reciprocity in iterative games, but not in single-iteration games measuring personal values.
  
  
  METHODS
  Participants (n=41) played four computer-based economic games (prisoner's dilemma, the public goods game, the ultimatum game, and the trust game) measuring different aspects of cooperation. Participants completed the Depression Anxiety and Stress Scale (DASS) and other measures of personality and demographics. Analyses assessed the relationships between game performance and psychological distress as measured by the DASS.
  
  
  RESULTS
  Significant correlations were found between game performance and depressive symptoms, but not symptoms of anxiety or stress. Performance in the prisoner's dilemma and public goods game was significantly related to depression in a linear regression even when known associations with depressive affect such as age, gender, race, education, marital status, and neuroticism were controlled for.
  
  
  CONCLUSIONS
  Depressive symptoms were associated with an inability to sustain reciprocal cooperation. Participants showed the predicted deficits in cooperation in these economic games. Economic games show the potential for assessing the social deficits associated with depressive symptoms.
authors.affiliation: University of Alabama at Birmingham, Department of Psychiatry & Behavioral Neurobiology, Birmingham, AL 35294-0017, USA. cbrendanclark@uab.edu
authors.forename: C
authors.initials: C
authors.lastname: Brendan Clark
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Thorne
authors.forename: Sonya
authors.initials: S
authors.lastname: Hardy
authors.forename: Karen L
authors.initials: KL
authors.lastname: Cropsey
mesh_terms: D000328:Adult; D001008:Anxiety Disorders / Q000150:complications; D003299:Cooperative Behavior; D003863:Depression / Q000150:complications / Q000523:psychology*; D060909:Economics, Behavioral; D005260:Female; D005716:Game Theory; D006801:Humans; D008297:Male; D000075384:Neuroticism; D035502:Trust; D055815:Young Adult
keywords: Behavioral economics; Cooperation; Depression; Prisoner's dilemma; Public goods game