title: Impulsivity in adult ADHD patients with and without cocaine dependence.
abstract: BACKGROUND
  Attention deficit hyperactivity disorder (ADHD) is present in about a quarter of patients with a substance use disorder (SUD) and impulsivity is a key feature of both disorders. However, very little is known about differences in impulse control and other cognitive functions between ADHD patients with and without SUD.
  
  
  METHODS
  In adult male medication-naïve ADHD patients with and without comorbid cocaine dependence and healthy controls (matched on gender, age and IQ), we measured motor impulsivity (stop signal task), cognitive impulsivity (delay discounting task), divided attention (trail making test), interference (Stroop task), working memory (n-back task), and time reproduction (time reproduction task). Additionally, self-reported ADHD symptoms (using the ADHD Symptom Rating Scale; ASRS) and self-reported impulsivity (Barratt Impulsivity Scale; BIS) were assessed.
  
  
  RESULTS
  Significantly higher levels of motor and cognitive impulsivity were found in ADHD patients with comorbid cocaine dependence compared to ADHD patients without cocaine dependence and controls, and both measures of impulsivity were highly correlated. No significant group differences were found on other cognitive measures. With regard to the self-report measures, only BIS attention subscores differed significantly between ADHD patients with and without cocaine dependence. ASRS and BIS scores were not significantly correlated.
  
  
  CONCLUSIONS
  This is the first study showing that ADHD patients with cocaine dependence are a distinctly more impulsive subpopulation compared to ADHD patients without cocaine dependence on objective measures of impulsivity. These findings are relevant to optimize psycho-education and treatment of ADHD patients with comorbid SUD.
authors.affiliation: Amsterdam Institute for Addiction Research and Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. cleo.crunelle@gmail.com
authors.forename: Cleo L
authors.initials: CL
authors.lastname: Crunelle
authors.forename: Dick J
authors.initials: DJ
authors.lastname: Veltman
authors.forename: Katelijne
authors.initials: K
authors.lastname: van Emmerik-van Oortmerssen
authors.forename: Jan
authors.initials: J
authors.lastname: Booij
authors.forename: Wim
authors.initials: W
authors.lastname: van den Brink
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology; D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications / Q000523:psychology*; D019970:Cocaine-Related Disorders / Q000150:complications / Q000523:psychology*; D003071:Cognition / Q000502:physiology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000523:psychology*; D007361:Intelligence Tests; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology; D011932:Reading; D057190:Stroop Test; D019966:Substance-Related Disorders / Q000523:psychology; D011795:Surveys and Questionnaires; D013998:Time Perception / Q000502:physiology; D014145:Trail Making Test