title: "Maturational lag" hypothesis of attention deficit hyperactivity disorder: an update.
abstract: This article discusses the relationship of maturation to ADHD and hyperkinetic disorder (HKD), with an emphasis on current research in ADHD and HKD, persistence and remission of ADHD symptoms over time and brain maturational trajectories.
  
  
  CONCLUSIONS
  ADHD is a broad, heterogeneous syndrome and only a subgroup of subjects has a diagnosis of HKD, which is a subset of individuals with severe ADHD combined subtype. Children showing symptoms above the threshold for a diagnosis of ADHD are at risk of developing comorbid conditions and increasing stress in both parents and teachers. In some subjects, ADHD symptoms can improve over time during maturation and development. These children with a diagnosis of ADHD could be viewed as showing variants of normal childhood behaviour with maturational trajectories that are lagging behind but will catch up. ADHD could therefore represent a continuum from normality at one extreme to a severe disorder, HKD according to ICD-10, at the other extreme.
authors.affiliation: Department of Woman and Child Health, Child and Adolescent Psychiatric Unit, Karolinska Institutet, Astrid Lindgren Children's Hospital, Karolinska Hospital, Stockholm, Sweden. Eman.El-Sayed@kbh.ki.se
authors.forename: E
authors.initials: E
authors.lastname: El-Sayed
authors.forename: J O
authors.initials: JO
authors.lastname: Larsson
authors.forename: H E
authors.initials: HE
authors.lastname: Persson
authors.forename: P J
authors.initials: PJ
authors.lastname: Santosh
authors.forename: P A
authors.initials: PA
authors.lastname: Rydelius
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology / Q000209:etiology* / Q000235:genetics; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology*; D002648:Child; D003072:Cognition Disorders / Q000209:etiology; D002658:Developmental Disabilities / Q000150:complications*; D004569:Electroencephalography; D006801:Humans; D001523:Mental Disorders / Q000209:etiology; D011930:Reaction Time / Q000502:physiology