Date of Award


Degree Name

Doctor of Philosophy



First Advisor

Kibby, Michelle


Deficits in Processing Speed (PS), a basic neuropsychological construct, are indicated in Attention Deficit Hyperactivity Disorder (Shanahan et al., 2006; Wilcutt, Pennington, Olson, Chhabildas, & Hulslander, 2005), as well as in Depression (Andersson, Lovdahl, & Malt, 2010). PS is correlated with Working Memory (WM), as established in the cognitive literature (Fry & Hale, 2000), and ADHD is significantly correlated with depression as evidenced in the clinical literature (Biederman et al., 2008). However, the current body of literature does not look into the capacity of inattention severity to predict PS, graphomotor versus primarily cognitive, in unmedicated, young adults, when depression and WM are controlled. Therefore, my study investigated the dimension of inattention as a predictor of graphomotor PS and cognitive PS, controlling for depression, and WM, in young adult students at Southern Illinois University Carbondale. Results indicated that the dimension of inattention did not predict motor or cognitive PS, when depression and WM were controlled. Thus it likely requires more severe symptoms of inattention for deficits in PS and WM. Depression symptoms were not predictive of graphomotor or cognitive PS supporting the hypothesis that neurocognitive deficits are not associated with mild or non-melancholic cases of depression. However, inattention was a significant predictor of depression, irrespective of gender. This relationship was independent of the severity of PS and WM deficits. The symptoms of inattention dropped significantly with age in my sample. The cognitive PS of the young adults was correlated with WM, as expected. Future research needs to focus on the extent to which PS and WM vary with regard to the severity of the dimensions of inattention and depression.




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