Previous research has failed to find a consistent relation between Sluggish Cognitive Tempo (SCT) and executive function (EF) in youth with Attention-Deficit/Hyperactivity Disorder (ADHD) when laboratory-based neuropsychological tasks of EF are used, whereas recent research with youth and adults suggests a significant relation between SCT and ratings of EF. The purpose of this study was to examine ADHD dimensions and SCT symptoms in relation to ratings of EF in adolescents with ADHD. Fifty-two adolescents (ages 12–16; 70 % male) participated in this study. Parents and teachers completed validated measures of SCT, ADHD symptoms, and EF in daily life. Adolescents’ intelligence and academic achievement were also assessed. ADHD and SCT symptoms were significantly correlated with ratings of EF. Regression analyses demonstrated that, as hypothesized, ADHD hyperactive-impulsive symptoms were strongly associated with behavioral regulation EF deficits, with ADHD inattentive and SCT symptoms unrelated to behavioral regulation EF when hyperactive-impulsivity symptoms were included in the model. The parent-reported SCT Slow scale measuring motivation, initiative, and apathy predicted both parent- and teacher-reported metacognitive EF deficits above and beyond youth characteristics and ADHD symptoms. In contrast, teacher-reported ADHD inattention was most clearly associated with teacher-reported metacognitive EF deficits. This study provides preliminary evidence for the importance of SCT symptoms in relation to metacognitive EF deficits among adolescents with ADHD and the need to further investigate the overlap and distinctiveness of SCT/ADHD. Further research is needed to replicate and extend these findings.
