Doctor of Philosophy, The Ohio State University, 2024, Psychology
Background: Approximately one-third of depression cases feature clinically elevated inflammation. The Social Signal Transduction Theory of Depression outlines one pathway to inflammation-driven depressive symptoms. It posits that those who report more frequent social stress and who have heightened inflammatory responses to an acute laboratory social stressor will have the greatest depressive symptom increases over time.
Aims: This series of studies tested the Social Signal Transduction Theory of Depression, and whether this pathway is specific to social stress. It also investigated whether omega-3 supplementation impedes this etiological pathway, especially among those who are socially stressed.
Methods: To test the Social Signal Transduction Theory of Depression, 76 physically healthy adults and 79 breast cancer survivors completed a laboratory social stressor (a marital conflict or the Trier Social Stress Test, respectively), had their blood drawn to assess inflammatory responsivity, and reported their stress exposure at baseline and their depressive symptoms at baseline and follow-up (one month later or four and eight months later, respectively). To test omega-3's effect on inflammatory responses, 138 middle-aged, sedentary adults were randomized to 2.5 g/day of omega-3, 1.25 g/day of omega-3, or placebo for four months. Before and after supplementation, they completed the Trier Social Stress Test and repeatedly had their blood drawn to assess inflammatory responsivity. The final study features secondary analyses from the same randomized, controlled trial to examine whether omega-3 reduced self-reported depressive symptoms among those who reported more social stress.
Results: In the first study, those who reported more frequent social stress, but not other types of stress, and had greater inflammatory responsivity at baseline had heightened depressive symptoms at follow-up. This effect was specific to social stress. In the second study, omega-3
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Committee: Janice Kiecolt-Glaser (Advisor); Michael Vasey (Committee Member); Charles Emery (Committee Member)
Subjects: Clinical Psychology; Immunology; Psychology