Original Articles

Cool and hot executive function in conduct-disordered adolescents with and without co-morbid attention deficit hyperactivity disorder: relationships with externalizing behaviours

M. Dolan^a1a2 c1 and C. Lennox^a3

^a1 Centre for Forensic Behavioural Science, Monash University, Victoria, Australia

^a2 The Victorian Institute of Forensic Mental Health, Melbourne, Australia

^a3 The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK

Abstract

Background An understanding of the exact nature of executive function (EF) deficits in conduct disorder (CD) remains elusive because of issues of co-morbidity with attention deficit hyperactivity disorder (ADHD).

Method Seventy-two adolescents with CD, 35 with CD + ADHD and 20 healthy controls (HCs) were assessed on a computerized battery of putative ‘cool’ and ‘hot’ EFs. Participants also completed the Child Behaviour Checklist (CBCL).

Results In the cool EF tasks such as planning, the CD + ADHD group in particular showed most notable impairments compared to HCs. This pattern was less evident for set shifting and behavioural inhibition but there were significant correlations between errors scores on these tasks and indices of externalizing behaviours on the CBCL across the sample. For hot EF tasks, all clinical groups performed worse than HCs on delay of gratification and poor performance was correlated with externalizing scores. Although there were no notable group differences on the punishment-based card-playing task, there were significant correlations between ultimate payout and externalizing behaviour across groups.

Conclusions Overall, our findings highlight the fact that there may be more common than distinguishing neuropsychological underpinnings to these co-morbid disorders and that a dimensional symptom-based approach may be the way forward.

(Received June 13 2012)

(Revised November 13 2012)

(Accepted November 19 2012)

Key words

• Attention deficit hyperactivity disorder;
• conduct disorder;
• executive behaviour;
• externalizing function

Correspondence:

^c1 Address for correspondence: Professor M. Dolan, Centre for Forensic Behavioural Science, Monash University, 505 Hoddle Street, Clifton Hill, VIC 3068, Australia. (Email: mairead.dolan@forensicare.vic.gov.au)