Date of Award

January 2021

Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Thomas Petros


Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder marked by symptoms of inattention, hyperactivity, and impulsivity. In addition to the well-known ADHD symptom clusters, a fourth dimension has been identified as sluggish cognitive tempo (SCT) and describes symptoms of sluggishness, drowsiness, and daydreaming. SCT represents a unique symptom domain than cannot be accounted for by the other ADHD dimensions. The current study sought to replicate and expand upon the extant literature, hypothesizing that ADHD/SCT symptoms would significantly predict: 1a) impairment in executive functioning on a self-report measure; 1b) impairment on laboratory measures of executive functioning; 2) symptoms of depression and anxiety; 3) symptoms of substance use disorders; and 4) symptoms of convergence insufficiency. These hypotheses were tested using a series of multiple linear regressions. A total of 103 university students completed this laboratory study. Results indicated ADHD/SCT symptoms significantly predicted impairment on self-reported, but not laboratory measures of executive functioning. SCT symptoms, but not any of the traditional ADHD dimensions, significantly predicted symptoms of depression and anxiety. Conversely, ADHD dimensions significantly predicted problematic substance use while SCT symptoms did not. Lastly, only SCT symptoms predicted symptoms of convergence insufficiency. Overall, these findings suggest that ADHD dimensions and SCT symptoms are distinct in predicting different deficits and comorbidities in a community sample of college students.