Does Sluggish Cognitive Tempo Fit Within a Bi-Factor Model of ADHD?

OBJECTIVE: Studies demonstrate sluggish cognitive tempo (SCT) symptoms to be distinct from inattentive and hyperactive-impulsive dimensions of ADHD. No study has examined SCT within a bi-factor model of ADHD, whereby SCT may form a specific factor distinct from inattention and hyperactivity/impulsivity while still fitting within a general ADHD factor, which was the purpose of the current study. METHOD: A total of 168 children were recruited from an ADHD clinic. Most (92%) met diagnostic criteria for ADHD. Parents and teachers completed measures of ADHD and SCT. RESULTS: Although SCT symptoms were strongly associated with inattention, they loaded onto a factor independent of ADHD g. Results were consistent across parent and teacher ratings. CONCLUSION: SCT is structurally distinct from inattention as well as from the general ADHD latent symptom structure. Findings support a growing body of research suggesting SCT to be distinct and separate from ADHD.