Multiple deficits in ADHD: executive dysfunction, delay aversion, reaction time variability, and emotional deficits.
BACKGROUND
The notion that ADHD constitutes a heterogeneous disorder is well accepted. However, this study contributes with new important knowledge by examining independent effects of a large range of neuropsychological deficits. In addition, the study investigated whether deficits in emotional functioning constitute a dissociable component of ADHD.


METHODS
The study included children with ADHD (n = 102; 7-13 years) and a control sample individually matched with regard to age and gender. The administered tasks were designed to tap into three different neuropsychological domains: executive functions (i.e., working memory, inhibition, and shifting), delay aversion, and reaction time variability. Parent ratings of emotion regulation and a test of emotion recognition were also included.


RESULTS
Children with ADHD differed significantly from controls on all measures, except for delay aversion and recognition of disgust. No main effects of gender or interaction effects of gender and group were found. More importantly, executive functioning, reaction time variability, and emotional functioning all contributed independently to distinguishing between children with ADHD and controls.


CONCLUSIONS
The current study supports the view of ADHD as a heterogeneous disorder related to multiple neuropsychological deficits. In addition, emotional functioning appears to be an area of importance for ADHD that needs to be incorporated into future theoretical models.
Department of Clinical Neuroscience and Stockholm Brain Institute, Karolinska Institutet, Stockholm, Sweden. douglas.sjowall@ki.se
Douglas
D
Sjöwall
Linda
L
Roth
Sofia
S
Lindqvist
Lisa B
LB
Thorell
D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis* / Q000523:psychology*; D002648:Child; D003937:Diagnosis, Differential; D056344:Executive Function; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000175:diagnosis* / Q000523:psychology*; D007266:Inhibition, Psychological; D008297:Male; D008570:Memory, Short-Term; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D009769:Object Attachment; D011594:Psychometrics; D011930:Reaction Time; D012016:Reference Values; D012193:Reversal Learning; D012718:Set, Psychology