title: Changes in cocaine consumption are associated with fluctuations in self-reported impulsivity and gambling decision-making.
abstract: BACKGROUND
  In cross-sectional studies, cocaine users generally display elevated levels of self-reported and cognitive impulsivity. To what extent these impairments are stable v. variable markers of cocaine use disorder, and, thus, are pre-existing or drug-induced, has not yet been systematically investigated.
  
  
  METHODS
  We conducted a longitudinal study with cocaine users who changed or maintained their consumption intensity, measuring self-reported impulsivity with the Barratt Impulsiveness Scale (BIS-11), and cognitive impulsivity with the Rapid Visual Processing task (RVP), Iowa Gambling task (IGT), and Delay Discounting task (DD) at baseline and at 1-year follow-up. We assessed 48 psychostimulant-naive controls and 19 cocaine users with decreased, 19 users with increased, and 19 users with unchanged cocaine intake after 1 year as confirmed by hair analysis.
  
  
  RESULTS
  Results of linear multilevel modelling showed significant group × time interactions for the BIS-11 total score and the IGT total card ratio. Increasers showed a trend for elevated scores, whereas decreasers exhibited reduced self-reported impulsivity scores within 1 year. Surprisingly, increasers' IGT performance was improved after 1 year, whereas decreasers' performance deteriorated. By contrast, neither RVP response bias B" nor DD total score showed substantial group × time interactions. Importantly, BIS-11 and DD revealed strong test-retest reliabilities.
  
  
  CONCLUSIONS
  Self-reported impulsivity (BIS-11) and decision-making impulsivity (IGT) covary with changing cocaine use, whereas response bias and delay discounting remain largely unaffected. Thus, self-reported impulsivity and gambling decision-making were strongly state-dependent in a stimulant-using population and may be suitable to monitor treatment success, whereas delay of gratification was confirmed as a potential endophenotype of stimulant addiction.
authors.affiliation: Experimental and Clinical Pharmacopsychology,Department of Psychiatry,Psychotherapy, and Psychosomatics, Psychiatric Hospital,University of Zurich,Switzerland.
authors.forename: L M
authors.initials: LM
authors.lastname: Hulka
authors.affiliation: Experimental and Clinical Pharmacopsychology,Department of Psychiatry,Psychotherapy, and Psychosomatics, Psychiatric Hospital,University of Zurich,Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Vonmoos
authors.affiliation: Experimental and Clinical Pharmacopsychology,Department of Psychiatry,Psychotherapy, and Psychosomatics, Psychiatric Hospital,University of Zurich,Switzerland.
authors.forename: K H
authors.initials: KH
authors.lastname: Preller
authors.affiliation: Center of Forensic Hairanalytics,Institute of Forensic Medicine,University of Zurich,Switzerland.
authors.forename: M R
authors.initials: MR
authors.lastname: Baumgartner
authors.affiliation: Director of the Department of Psychiatry,Psychotherapy, and Psychosomatics,Psychiatric Hospital,University of Zurich,Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Seifritz
authors.affiliation: Division of ADHD Research,Department of Psychiatry, Psychotherapy, and Psychosomatics,Psychiatric Hospital,University of Zurich,Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Gamma
authors.affiliation: Experimental and Clinical Pharmacopsychology,Department of Psychiatry,Psychotherapy, and Psychosomatics, Psychiatric Hospital,University of Zurich,Switzerland.
authors.forename: B B
authors.initials: BB
authors.lastname: Quednow
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D003042:Cocaine / Q000009:adverse effects*; D019970:Cocaine-Related Disorders / Q000523:psychology*; D003430:Cross-Sectional Studies; D003657:Decision Making / Q000187:drug effects*; D065786:Delay Discounting / Q000187:drug effects*; D005260:Female; D005500:Follow-Up Studies; D005715:Gambling / Q000523:psychology*; D006801:Humans; D007175:Impulsive Behavior / Q000187:drug effects*; D008137:Longitudinal Studies; D008297:Male; D009483:Neuropsychological Tests; D057566:Self Report; D055815:Young Adult
chemical_list: D003042:Cocaine
keywords: Addiction; drug dependence; impulse control; intertemporal choice; planning; stimulants; temporal discounting