Date of Award

Winter 3-8-2016

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Clinical Psychology (PhD)

Department

Clinical Psychology

First Advisor/Committee Member

Amy Mezulis

Second Advisor/Committee Member

Lynette H. Bikos

Third Advisor/Committee Member

Thane Erickson

Abstract

Trait levels of negative affect (NA) and positive affect (PA) are established risk factors for depressive symptoms (Clark & Watson, 1991), but the mechanisms through which high NA and low PA confer risk for depression are poorly understood. Two proposed mechanisms in the transmission of affective vulnerabilities to depression are the cognitive responses of brooding and positive rumination. Brooding and positive rumination may represent a common cognitive process that amplifies the intensity of affect and contributes to depressive symptoms. Therefore, my dissertation purposes were to (a) determine whether brooding and positive rumination represent a shared cognitive process on distinct affective content and (b) examine brooding and positive rumination as cognitive mechanisms through which NA and PA predict depressive symptoms with an 8-week, prospective design among adults. I hypothesized that brooding and positive rumination would be best modeled as distinct but related factors (Model 2). I also hypothesized that greater brooding and less positive rumination would mediate the relationships between greater NA and less PA in predicting greater depressive symptoms. I first compared three confirmatory factor analysis models of the relationship between brooding and positive rumination as distinct constructs, as the same construct, and as distinct but related constructs to determine how these constructs relate. Thereafter, I utilized structural equation modeling to examine whether brooding and positive rumination mediated the relationship between trait affect and depressive symptoms.

Participants were 321 (73.5% female) undergraduate students (M=19.03, SD=1.64). Participants completed online measures of trait affect, cognitive responses, and depressive symptoms at baseline and again completed an online measure of depressive symptoms seven weeks after baseline assessment. Results indicated that Model 2 best fit the data (χ=195.07, Δχ=8.78, p<.001, CFI=.91, RMSEA=.07), supporting a conceptualization of brooding and positive rumination as distinct but related constructs. Results further indicated that greater NA and less PA distinctly predicted greater depressive symptoms through greater brooding (βNA=.08, p=.007; βPA=-.02, p=.038), but positive rumination did not mediate either relationship (βNA=.01, p=.443; (βPA=.01, p=.441). Findings contribute to an integrated theoretical understanding of the joint contributions of brooding and positive rumination in the relationship between trait affect and depressive symptoms.

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