Inhibition and working memory in young preschool children with symptoms of ADHD and/or oppositional-defiant disorder.
BACKGROUND
Early symptoms of attention deficit/hyperactivity disorder (ADHD) and oppositional-defiant disorder (ODD) are associated with deficits in cognitive self-regulatory processes or executive functions (EF)s. However, the hypothesis that neurocognitive deficits underlying the two disorders are already evident during early preschool years still has limited empirical support. The present study investigated associations between symptoms of ADHD and/or ODD and two core EFs, inhibition and working memory, in a large nonclinical sample of 3-year old children.


METHODS
Participants were 1045 children (554 boys, age 37-47 months), recruited from the population based Norwegian Mother and Child Cohort Study (MoBa). Relations between behavioral symptoms and measures of inhibition and working memory were studied both categorically and dimensionally.


RESULTS
Children with co-occurring symptoms of ADHD and ODD performed at a significantly lower level than typically developing children in 4 out of 5 EF measures. Symptoms of ADHD, both alone and in combination with ODD, were associated with reduced performance on tests of inhibition in the group comparisons. Dimensional analyses showed that performance within both EF domains contributed to variance primarily in ADHD symptom load. The associations between test results and behavioral symptoms remained significant after gender and verbal skills had been controlled.


CONCLUSIONS
Young preschoolers show the same pattern of relations between EF and behavioral symptoms of ADHD and/or ODD as previously described in older children diagnosed with ADHD and/or ODD. Effect sizes were generally small, indicating that measures of EF have limited clinical utility at this stage in development.
a Oslo University Hospital, Child and Adolescent Mental Health Research Unit , Oslo , Norway.
Annette Holth
AH
Skogan
Pål
P
Zeiner
Jens
J
Egeland
Nina
N
Rohrer-Baumgartner
Anne-Grethe
AG
Urnes
Ted
T
Reichborn-Kjennerud
Heidi
H
Aase
D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000523:psychology*; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000523:psychology*; D002675:Child, Preschool; D015331:Cohort Studies; D015897:Comorbidity; D015986:Confounding Factors, Epidemiologic; D056344:Executive Function; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008570:Memory, Short-Term; D009664:Norway; D012107:Research Design
ADHD; Development; Executive functions; ODD; Preschool children