Sluggish cognitive tempo and processing speed in adolescents with ADHD: do findings vary based on informant and task?

Few studies have examined whether behavioral sluggish cognitive tempo (SCT) symptoms are related to speeded task performance. Mixed findings in existing research could be due to previous studies using a broad conceptualization of processing speed, not including self-report of SCT symptoms, and relying on non-optimal measures of SCT. Using a multi-informant design with both parent- and adolescent-reported SCT symptoms, the present study provides a preliminary test of the hypothesis that SCT symptoms would be associated with slower performance on tasks having greater graphomotor and fine motor demands. Participants were 80 adolescents (ages 13-17 years; 71% male) with attention-deficit/hyperactivity disorder (ADHD). Adolescents and parents completed ratings of SCT. Adolescents were administered the Wechsler Symbol Search and Coding subtests and the Grooved Pegboard Test. When adjusting for age, sex, and ADHD symptom severity, parent-reported SCT symptoms were not significantly associated with Symbol Search or Coding scores but were significantly associated with slower Grooved Pegboard time. Adolescent-reported SCT symptoms were not significantly associated with Symbol Search but were significantly associated with lower Coding scores and slower Grooved Pegboard time. Findings provide preliminary support for the hypothesis that SCT may be more clearly associated with processing speed task performance as motor demands increase and provide a potential explanation for the mixed literature on SCT in relation to processing speed by demonstrating that the presence and magnitude of associations vary by informant and task.