Date of Award
Doctor of Philosophy
Sleep problems are common among college students and are associated with numerous negative outcomes including anxiety, depression, executive dysfunction, and poor academic performance. When sleep is limited, individuals may suffer impaired cognitive capacities, such as reduced memory and difficulty focusing attention. Difficulty with these cognitive functions can result in difficulty disengaging from negative thoughts, thereby contributing to negative mood. Poor sleep contributes to negative mood states, but few studies have examined in what way poor sleep may exacerbate negative mood. The purpose of this study was to examine cognitive factors as explanatory variables between sleep and state affect. Participants were undergraduate students from a university in the Midwest. Participants (N = 150, completed baseline questionnaires and wore an actigraphy watch for one night. They returned to the lab the following day to complete additional self-report measures and a computerized cognitive control task. Participants were primarily female (66.67%, n = 100) and white (67.33%, n = 101). To test the hypothesis that the relationship between sleep and affect is explained by cognitive factors, a path analytic model was fit to the data. It was hypothesized that cognitive factors (i.e., Posner task performance, repetitive negative thinking, and self-report attention control) would explain the relationship between sleep (as measured by objective total sleep time and self-report sleepiness) and state affect. The hypothesized model yielded poor global and local fit to the data. While several direct effects emerged in the model, no indirect effects were statistically significant. The model was re-specified, adding paths where large magnitude correlational residual statistics coincided with statistically significant standardized residual statistics. The final model yielded good global and local fit to the data, with primary modifications being added covariances among control variables (e.g., GAD-7 and PHQ-8 scores) with cognitive factors. Overall, the results of this study indicate that the relationship between sleep and next-day affect is complex and cannot be simply explained by cognitive factors. However, the current study found several significant relationships among study variables, suggesting that sleep, cognitive functioning, and emotion are highly related constructs that warrant further study. Future research should examine alternative models incorporating these constructs to find a comprehensive model with utility that can explain the relationships among these constructs.
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