title: ADHD subtypes and co-occurring anxiety, depression, and oppositional-defiant disorder: differences in Gordon diagnostic system and Wechsler working memory and processing speed index scores.
abstract: OBJECTIVE
  Wechsler Intelligence Scale for Children Freedom-from-Distractibility/Working Memory Index (FDI/WMI), Processing Speed Index (PSI), and Gordon Diagnostic System (GDS) scores in ADHD children were examined as a function of subtype and coexisting anxiety, depression, and oppositional-defiant disorder.
  
  
  METHODS
  Participants were 587 children with ADHD combined type (alone, with oppositional-defiant disorder, and with anxiety or depression) and ADHD inattentive type (alone and with anxiety or depression).
  
  
  RESULTS
  Attention scores (FDI/WMI and GDS Vigilance and Distractibility) were similar and low for all groups. ADHD combined groups had greater impulsivity (GDS Delay) than ADHD inattentive groups, and ADHD inattentive groups had slower processing speed (PSI) than ADHD combined groups. Comorbidity did not affect test performance. Scores differentiated ADHD subtypes with 72% accuracy.
  
  
  CONCLUSIONS
  Findings support the validity of DSM-IV ADHD combined and inattentive subtypes and the validity of the GDS, FDI/WMI, and PSI in assessing attention, impulsivity, and processing speed in children with ADHD.
authors.affiliation: Penn State College of Medicine, Milton S. Hershey Medical Center, Department of Psychiatry, Hershey, PA 17033, USA. smayes@psu.edu
authors.forename: Susan Dickerson
authors.initials: SD
authors.lastname: Mayes
authors.forename: Susan L
authors.initials: SL
authors.lastname: Calhoun
authors.forename: Gary A
authors.initials: GA
authors.lastname: Chase
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Mink
authors.forename: Ryan E
authors.initials: RE
authors.lastname: Stagg
mesh_terms: D000293:Adolescent; D001008:Anxiety Disorders / Q000175:diagnosis / Q000453:epidemiology*; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D002648:Child; D015897:Comorbidity; D003866:Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D003937:Diagnosis, Differential; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data*; D011594:Psychometrics; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D014888:Wechsler Scales / Q000706:statistics & numerical data