title: Effects of working memory load, a history of conduct disorder, and sex on decision making in substance dependent individuals.
abstract: BACKGROUND
  Substance dependence and antisocial psychopathology, such as a history of childhood conduct disorder (HCCD), are associated with impulsive or disadvantageous decision making and reduced working memory capacity (WMC). Reducing WMC via a working memory load increases disadvantageous decision making in healthy adults, but no previous studies have examined this effect in young adults with substance dependence and HCCD.
  
  
  METHODS
  Young adults with substance dependence (SubDep; n=158, 71 female), substance dependence and HCCD (SubDep+HCCD; n=72, 24 female), and control participants (n=152, 84 female) completed a test of decision making (the Iowa Gambling Task; IGT) with or without a concurrent working memory load intended to tax WMC. Outcomes were (i) net advantageous decisions on the IGT, and (ii) preferences for infrequent- versus frequent-punishment decks.
  
  
  RESULTS
  SubDep+HCCD men made fewer advantageous decisions on the IGT than control men without a load, but there were no group differences among women in that condition. Load was associated with fewer advantageous decisions for SubDep+HCCD women and control men, but not for men or women in the other groups. Participants showed greater preference for infrequent-punishment, advantageous decks under load as well.
  
  
  CONCLUSIONS
  There are gender differences in the effects of substance dependence, HCCD, and working memory load on decision making on the IGT. Decision making by control men and SubDep+HCCD women suffered the most under load. Load increases preferences for less-frequent punishments, similar to a delay discounting effect. Future research should clarify the cognitive and neural mechanisms underlying these effects.
authors.affiliation: Department of Psychological and Brain Sciences, Indiana University Bloomington, 1101 East 10th Street, Bloomington, IN 47405, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Fridberg
authors.forename: Kyle R
authors.initials: KR
authors.lastname: Gerst
authors.forename: Peter R
authors.initials: PR
authors.lastname: Finn
mesh_terms: D000293:Adolescent; D000328:Adult; D000437:Alcoholism / Q000523:psychology; D000704:Analysis of Variance; D019955:Conduct Disorder / Q000523:psychology*; D003657:Decision Making / Q000502:physiology*; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000523:psychology; D007361:Intelligence Tests; D008297:Male; D002189:Marijuana Abuse / Q000523:psychology; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests; D011678:Punishment; D012055:Reinforcement Schedule; D012727:Sex Characteristics; D019966:Substance-Related Disorders / Q000523:psychology*; D055815:Young Adult
keywords: Conduct disorder; Decision-making; Substance dependence; Working memory capacity