title: A longitudinal examination of neuropsychological and clinical functioning in boys with attention deficit hyperactivity disorder (ADHD): improvements in executive functioning do not explain clinical improvement.
abstract: BACKGROUND
  Attention deficit hyperactivity disorder (ADHD) often, but not always, persists into adulthood. Investigations of the associations between clinical and biological markers of persistence can shed light on causal pathways. It has been proposed that compensatory improvements in executive neuropsychological functioning are associated with clinical improvements. This is the first study to test this hypothesis prospectively.
  
  
  METHODS
  The clinical and neuropsychological functioning of 17 boys with ADHD (mean age 10.45 years at time 1; 14.65 years at time 2) and 17 typically developing (TYP) boys (mean age 10.39 years at time 1; 14.47 years at time 2) was tested on two occasions, 4 years apart. This was done using a battery of standardized neuropsychological tests that included tasks with high and low executive demands.
  
  
  RESULTS
  Clinical improvements were observed over time. Neuropsychological performance improvements were also evident, with ADHD boys developing with a similar pattern to TYP boys, but with a developmental lag. Whilst there was an association between reduced symptoms and superior performance at retest for one task with a high executive demand (spatial working memory), this was not seen with two further high executive demand tasks [Stockings of Cambridge and intra-dimensional extra-dimensional (ID/ED) set shifting]. Also, there was no association between change in executive functioning and change in symptoms. Baseline performance on the ID/ED set-shifting task predicted better clinical outcome. Only change in performance on the low executive demand delayed matching-to-sample task predicted better clinical outcome.
  
  
  CONCLUSIONS
  These data highlight the importance of longitudinal measurements of cognition, symptoms and treatment response over time in children and adolescents with ADHD.
authors.affiliation: Division of Neuroscience, Medical Research Institute, University of Dundee, Ninewells Hospital, Dundee, UK.
authors.forename: D R
authors.initials: DR
authors.lastname: Coghill
authors.affiliation: NHS Tayside, Murray Royal Hospital, Perth, UK.
authors.forename: D
authors.initials: D
authors.lastname: Hayward
authors.affiliation: School of Psychological Sciences and Health, University of Strathclyde, Graham Hills Building, Glasgow, UK.
authors.forename: S M
authors.initials: SM
authors.lastname: Rhodes
authors.affiliation: NHS Fife Child and Adolescent Mental Health Services, Stratheden Hospital, Stratheden, Cupar, Fife, UK.
authors.forename: C
authors.initials: C
authors.lastname: Grimmer
authors.affiliation: Division of Neuroscience, Medical Research Institute, University of Dundee, Ninewells Hospital, Dundee, UK.
authors.forename: K
authors.initials: K
authors.lastname: Matthews
mesh_terms: D000293:Adolescent; D041923:Adolescent Development / Q000502:physiology*; D001289:Attention Deficit Disorder with Hyperactivity / Q000503:physiopathology*; D002648:Child; D018450:Disease Progression; D056344:Executive Function / Q000502:physiology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male