Do executive function deficits differentiate between adolescents with ADHDand Oppositional Defiant/Conduct Disorder? A neuropsychological study using the Six Elements Test and Hayling Sentence Completion Test

Two neuropsychological measures of executive functions-Six Elements Tests ( SET) and Hayling Sentence Completion Test (HSCT)-were administered to 110 a dolescents, aged 12-15 years. Participants comprised four groups: Attention Deficit Hyperactivity Disorder (ADHD) only (n = 35), ADHD and Oppositional Defiant Disorder/Conduct Disorder (ODD/CD) (n = 38), ODD/CD only (n = I I) , and a normal community control group (n = 26). Results indicated that ado lescents with ADHD performed significantly worse on both the SET and HSCT t han those without ADHD, whether or not they also had ODD/CD. The adolescent s with ADHD and with comorbid ADHD and ODD/CD were significantly more impai red in their ability to generate strategics and to monitor their ongoing be havior compared with age-matched controls and adolescents with ODD/CD only. It is argued that among adolescents with clinically significant levels of externalizing behavior problems, executive function deficits are specific t o those with ADHD. The findings support the sensitivity of these two relati vely new tests of executive functions and their ecological validity in tapp ing into everyday situations, which are potentially problematic for individ uals with ADHD.