Publication Date

2012-08-06

Availability

Open access

Embargo Period

2012-08-06

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Psychology (Arts and Sciences)

Date of Defense

2012-05-07

First Committee Member

Jutta Joormann

Second Committee Member

Matthias Siemer

Third Committee Member

Frank J. Penedo

Fourth Committee Member

Debra Lieberman

Fifth Committee Member

Mahendra Kumar

Abstract

Diathesis-stress models of depression highlight that stress triggers the onset of a depressive episode. Increasing evidence, however, suggest that increased risk comes not from the initial response to stress, but rather from difficulty regulating emotions in a way that facilitates recovery. Rumination is a maladaptive emotion regulation strategy shown to prolong negative affect in response to distress. The current study extends past research by comparing the effects of a rumination versus distraction induction on biological and psychological recovery from stress among individuals with major depressive disorder (MDD) and healthy controls (CTLs). Participants were exposed to a psychosocial stressor and then randomly assigned to either the rumination or distraction condition. Self-reported affect and markers of biological arousal (salivary cortisol and respiratory sinus arrhythmia; RSA) were assessed before, during, and after the stressor. Participants demonstrated significant reactivity to stress, evidenced by an increase in self-reported negative affect and decrease in RSA. In contrast, participants did not demonstrate the expected significant cortisol reactivity to stress. Also unexpected was a significant increase in RSA during the latter-half of the stressor, suggesting spontaneous parasympathetic recovery. Although no group differences were seen in stress reactivity, significant time by group by condition interactions were seen in stress recovery. Within the CTL group, participants in the rumination and distraction conditions did not differ in their psychological or biological recovery from stress. Within the MDD group, however, participants in the rumination condition demonstrated higher negative affect and salivary cortisol during the recovery period than participants in the distraction condition. Evidence therefore suggests that rumination affects neuroendocrine and psychological recovery from stress in depression. Moreover, depressed participants in the distraction condition demonstrated significantly greater RSA withdrawal during the ER induction compared to control participants in the distraction condition, potentially suggesting that distraction was more effortful for the MDD versus CTL group. During the subsequent nature video, RSA recovery was greater in the MDD versus CTL group. Results from this study provide important insights into the effect of rumination on psychological and biological recovery from stress in MDD.

Keywords

major depressive disorder; rumination; cortisol; respiratory sinus arrhythmia; stress

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