Date of Graduation

Spring 2019


Master of Science in Psychology



Committee Chair

Steve Capps


Substance use is pervasive in the United States. With overdose deaths on the rise for the past decade, studies have examined the detrimental effects of a range of substances. Substance use has been shown to affect the domains of executive functioning, while diseases such as Human Immunodeficiency Virus (HIV) and Hepatitis-C (Hep-C) have been shown to increase the severity of these deficits when comorbid with substance use. Alzheimer’s Dementia (AD) also affects many of the same domains of executive functioning as substance use. However, because of the rapid degenerative nature of the disease, individuals clinically determined to have Mild Cognitive Impairment (MCI) with a risk of progression to AD are more uniform in symptom presentation and discerned deficits, and are therefore more feasible to examine. This study examined whether a history of substance abuse impairs executive function in a cumulative manner when comorbid with MCI with a clinically indicated risk of progression to AD. While those subject to both MCI and substance use history did have the lowest scores in all of the assessments and in each of the conditions measured, those differences were insignificant. The hypothesis was not supported, even though the trend in scores was in the predicted trajectory. These results and implications are discussed, while limitations and possible future research directions are outlined.


executive function, substance use, mild cognitive impairment, dementia, additive effects, comorbidity, Digit Span, Trail Making Test, COWAT

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© William C. Dooley

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