title: Executive Functioning in Subtypes of Attention Deficit Hyperactivity Disorder.
abstract: BACKGROUND
  This study aims to evaluate executive functions (EF), such as inhibition, planning, working memory, and set shifting, in children with attention deficit hyperactivity disorder (ADHD) by comparing three ADHD subtype groups (ADHD-Inattentive, ADHD-Combined, and ADHD-Comorbid) and a normal control group.
  
  
  METHODS
  Participants included 147 children. In total, 111 children were assigned to the ADHD groups of the study. Each child was matched according to the WISC-R Full-Scale IQ-score, sex, and age and was grouped as follows: ADHD-Inattentive group (ADHD-I; n=37), ADHD-Combined (ADHD-C; n=37), ADHD-Comorbid group (ADHD-Comorbid with oppositional defiant disorder and/or conduct disorder; n=37), and control group (n=36). The tests used to assess the children were Conners' Parent and Teacher Rating Scales; Wechsler Intelligence Scale-Revised; Tower of London test; Wisconsin Card Sorting Test; Stroop Color-Word Test, and verbal fluency test. The data were analyzed by one-way ANOVA between subjects for all dependent variables.
  
  
  RESULTS
  Children in the ADHD-I group had significantly better performances in verbal working memory and verbal category shifting than children in the ADHD-C group. There was no significant difference between the ADHD-I and ADHD-C groups in terms of inhibition, set shifting, verbal fluency, cognitive flexibility, and planning. The ADHD-Comorbid group displayed more severe impairments in EF measures than the ADHD-C group; however, the severity was not statistically significant. EF performances of children in the control group were similar to children in the ADHD-I group but better than children in the ADHD-C and ADHD-Comorbid groups.
  
  
  CONCLUSIONS
  The outcome of the study indicated that subjects in the ADHD-Comorbid and ADHD-C groups had more severe EF deficits than subjects in the ADHD-I and control groups.
authors.affiliation: Department of Child and Adolescent Psychiatry, İstanbul University İstanbul Faculty of Medicine, İstanbul, Turkey.
authors.forename: Reyhan
authors.initials: R
authors.lastname: Bahçivan Saydam
authors.affiliation: Department of Psychology, Orta Doğu Technical University Faculty of Arts and Sciences, Ankara, Turkey.
authors.forename: H Belgin
authors.initials: HB
authors.lastname: Ayvaşik
authors.affiliation: Department of Child and Adolescent Psychiatry, İstanbul University İstanbul Faculty of Medicine, İstanbul, Turkey.
authors.forename: Behiye
authors.initials: B
authors.lastname: Alyanak
keywords: ADHD; comorbidity; executive functions; neuropsychology; subtypes