Sluggish Cognitive Tempo, Internalizing Symptoms, and Executive Function in Adults With ADHD

Objective: We sought to characterize relationships between sluggish cognitive tempo (SCT) and both internalizing symptoms and executive functioning in adults with ADHD. Method: A total of 102 adults with ADHD completed clinical interviews and clinical rating scales. Hierarchical regression analyses were conducted to ascertain the independent predictive power of SCT symptoms for deficits in executive function (EF) after considering severity of ADHD inattentive and hyperactive-impulsive symptoms and internalizing symptoms. Results: SCT correlated with ADHD inattentive symptoms and dimensional measures of depression and anxiety but not with clinical diagnosis of depression or anxiety. SCT predicted EF deficits over and above the effects of internalizing and ADHD symptoms. This relationship between SCT and EF was limited to the subset of participants (n = 48) receiving stimulant treatment. Conclusion: SCT in adults with ADHD is associated with internalizing symptoms, ADHD inattentive symptoms, and, independently, with EF deficits. Further research is needed to ascertain why this relationship occurred primarily in adults concurrently receiving stimulants.