Dissertations, Theses, and Capstone Projects

Date of Degree

2-2016

Document Type

Dissertation

Degree Name

Ph.D.

Program

Psychology

Advisor

Regina Miranda

Committee Members

Victoria Luine

Mariann Weierich

Elizabeth Jeglic

Joel Erblich

Subject Categories

Biological Psychology | Cognitive Psychology

Keywords

Suicide, HPA Axis, 5-HTTLPR, Rumination, Negative Urgency, Impulsivity

Abstract

Suicide is one of the leading causes of death in young adults in the United States. Previous research has established distal and proximal life stress as a strong risk factor for suicidal behavior. However, how stress impacts suicidal behavior via interactive cognitive and biological mechanisms has not been thoroughly examined. The present research sought to better understand the relationship between stress and suicidal behavior via altered neurobiological functioning, maladaptive cognitions, and deficits in executive functioning. The first study found a relationship between the brooding subtype of rumination and trait impulsivity in the forms of negative urgency, lack of premeditation, and lack of perseverance. Further, lack of premeditation and lack of perseverance mediated the relationship between brooding and suicide risk. The second study found no difference in physiological stress response (as determined by cortisol levels), measures of executive functioning, and semantic interference from suicide-related stimuli among suicide attempters and non-attempters following a social rejection task. However, there was a positive association between suicide attempt history and negative urgency, lack of perseverance, and lack of premeditation. The final study found that early life stress was positively associated with brooding, negative urgency, recent suicidal ideation, and previous suicide attempt history. Additionally, a positive relationship between early life emotional abuse and negative urgency was mediated by brooding among individuals with serotonin transporter low expressing genotypes but not among those with high expressing genotypes. Overgeneral autobiographical memory was not associated with brooding or negative urgency. Implications for future research and developing targeted clinical interventions are discussed.

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