Graduation Semester and Year
Spring 2024
Language
English
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Kinesiology
Department
Kinesiology
First Advisor
Jody Greaney
Second Advisor
Paul Fadel
Third Advisor
Daniel Trott
Fourth Advisor
Tracy Greer
Fifth Advisor
David Almeida
Abstract
Major depressive disorder (MDD) is a mood disorder characterized by persistently depressed mood and/or anhedonia that causes significant functional impairment in daily life. MDD affects nearly 15% of adults in their lifetime, and since 2019, prevalence estimates have increased up to ~30% in young adults (18-25 years old). In addition to its debilitating effects on daily functioning, epidemiological studies link MDD to ~3 times greater risk of cardiovascular disease (CVD), followed by accelerated CVD progression and mortality. Although the mechanisms contributing to MDD-CVD comorbidity are unclear, there is evidence of stress system dysfunction in adults with MDD.
Accordingly, the aim of this dissertation is to investigate whether and how potential alterations to the stress response contribute to elevated CVD risk in young adults with MDD. It is well-established that greater sympathetic-cardiovascular responses to acute laboratory stressors predicts the development of future CVD risk. As such, study 1 tested the hypothesis that the magnitude of increase (i.e., reactivity) in muscle sympathetic nerve activity (MSNA) and blood pressure (BP) in response to acute stress would be greater in young adults with MDD compared to healthy non-depressed adults (HA). Although the findings indicate that sympathetic and cardiovascular reactivity to acute stress is preserved compared to HA, we show that greater depressive symptom severity predicts greater cardiovascular reactivity to a generalized sympathoexcitatory stress stimulus in young adults with MDD. In contrast to these physiological responses to stress, there is evidence to suggest that adults with MDD may be uniquely susceptible to the emotional consequences of stress in their everyday lives, which has been more closely linked to the development of future chronic diseases than merely stress exposure. In study 2, we aimed to determine whether and how depressive symptom severity is related to daily stressor exposure as well as the magnitude of change in negative, and separately positive, affect on days with at least one stressor compared to stressor free days (i.e., affective responsivity). We found that greater depressive symptom severity was associated with both greater exposure and negative affective responsivity to daily stressors. Lastly, given that affective responsivity and acute sympathetic-cardiovascular reactivity separately predict CVD risk and both are highly variable between individuals, study 3 tested the hypothesis that increased frequency of exposure and negative affective responsivity to daily stress would be associated with greater sympathetic-cardiovascular reactivity to acute stress. Further, we hypothesized that this relation would be moderated by MDD, such that the slope of this relation will be steeper in young adults with MDD compared to HA. The novel major findings are that 1) increased frequency of daily stressor exposure was related to greater HR, and blunted MSNA, reactivity to acute stress, 2) greater negative affective responsivity was associated with greater HR reactivity, and 3) MDD moderated this relation, such that greater negative affective responsivity was related to greater HR reactivity to acute stress in adults with MDD, but not HA. Taken together, these data provide additional insight into the complex interrelations between stress, depression, and the sympathetic reflex axis in contributing to heightened CVD risk.
Keywords
Depression, Muscle sympathetic nerve activity, Microneurography, Cold pressor test, Positive affect, Negative affect, Daily stress, Sympathetic reactivity, Blood pressure reactivity, Depressive symptom severity
Disciplines
Biological Psychology | Mental Disorders | Other Social and Behavioral Sciences | Psychiatric and Mental Health | Systems and Integrative Physiology
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Darling, Ashley, "Sympathetic-Cardiovascular Stress Reactivity in Adults with Major Depressive Disorder" (2024). Kinesiology Dissertations. 2.
https://mavmatrix.uta.edu/kinesiology_dissertations/2
Included in
Biological Psychology Commons, Mental Disorders Commons, Other Social and Behavioral Sciences Commons, Psychiatric and Mental Health Commons, Systems and Integrative Physiology Commons