title: ADHD comorbidity findings from the MTA study: comparing comorbid subgroups.
abstract: OBJECTIVE
  Previous research has been inconclusive whether attention-deficit/hyperactivity disorder (ADHD), when comorbid with disruptive disorders (oppositional defiant disorder [ODD] or conduct disorder [CD]), with the internalizing disorders (anxiety and/or depression), or with both, should constitute separate clinical entities. Determination of the clinical significance of potential ADHD + internalizing disorder or ADHD + ODD/CD syndromes could yield better diagnostic decision-making, treatment planning, and treatment outcomes.
  
  
  METHODS
  Drawing upon cross-sectional and longitudinal information from 579 children (aged 7-9.9 years) with ADHD participating in the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA), investigators applied validational criteria to compare ADHD subjects with and without comorbid internalizing disorders and ODD/CD.
  
  
  RESULTS
  Substantial evidence of main effects of internalizing and externalizing comorbid disorders was found. Moderate evidence of interactions of parent-reported anxiety and ODD/CD status were noted on response to treatment, indicating that children with ADHD and anxiety disorders (but no ODD/CD) were likely to respond equally well to the MTA behavioral and medication treatments. Children with ADHD-only or ADHD with ODD/CD (but without anxiety disorders) responded best to MTA medication treatments (with or without behavioral treatments), while children with multiple comorbid disorders (anxiety and ODD/CD) responded optimally to combined (medication and behavioral) treatments.
  
  
  CONCLUSIONS
  Findings indicate that three clinical profiles, ADHD co-occurring with internalizing disorders (principally parent-reported anxiety disorders) absent any concurrent disruptive disorder (ADHD + ANX), ADHD co-occurring with ODD/CD but no anxiety (ADHD + ODD/CD), and ADHD with both anxiety and ODD/CD (ADHD + ANX + ODD/CD) may be sufficiently distinct to warrant classification as ADHD subtypes different from "pure" ADHD with neither comorbidity. Future clinical, etiological, and genetics research should explore the merits of these three ADHD classification options.
authors.affiliation: Center for the Advancement of Children's Mental Health, Columbia University/NYSPI, 1051 Riverside Drive, Unit 78, New York, NY 10032, USA. pj131@columbia.edu
authors.forename: P S
authors.initials: PS
authors.lastname: Jensen
authors.forename: S P
authors.initials: SP
authors.lastname: Hinshaw
authors.forename: H C
authors.initials: HC
authors.lastname: Kraemer
authors.forename: N
authors.initials: N
authors.lastname: Lenora
authors.forename: J H
authors.initials: JH
authors.lastname: Newcorn
authors.forename: H B
authors.initials: HB
authors.lastname: Abikoff
authors.forename: J S
authors.initials: JS
authors.lastname: March
authors.forename: L E
authors.initials: LE
authors.lastname: Arnold
authors.forename: D P
authors.initials: DP
authors.lastname: Cantwell
authors.forename: C K
authors.initials: CK
authors.lastname: Conners
authors.forename: G R
authors.initials: GR
authors.lastname: Elliott
authors.forename: L L
authors.initials: LL
authors.lastname: Greenhill
authors.forename: L
authors.initials: L
authors.lastname: Hechtman
authors.forename: B
authors.initials: B
authors.lastname: Hoza
authors.forename: W E
authors.initials: WE
authors.lastname: Pelham
authors.forename: J B
authors.initials: JB
authors.lastname: Severe
authors.forename: J M
authors.initials: JM
authors.lastname: Swanson
authors.forename: K C
authors.initials: KC
authors.lastname: Wells
authors.forename: T
authors.initials: T
authors.lastname: Wigal
authors.forename: B
authors.initials: B
authors.lastname: Vitiello
mesh_terms: D000704:Analysis of Variance; D001008:Anxiety Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000145:classification* / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D002648:Child; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009656:North America / Q000453:epidemiology; D015203:Reproducibility of Results