Addressing Critical Gaps in the Study of Suicide: Testing Key Predictions of the Interpersonal Theory of Suicide about Perceived Burdensomeness, Thwarted Belongingness, and Capability for Suicide, and Accounting for the Role of Zest for Life

This thesis sought to address critical gaps in the literature on the interpersonal theory of suicide. First, three core assumptions regarding the theory's two putative causes of suicidal desire, perceived burdensomeness and thwarted belongingness, were tested experimentally. Key predictions about the theory's third pillar, the acquired capability for suicide, in transforming suicidal thoughts into lethal behavior were next examined longitudinally. Finally, the protective influence of zest for life was tested against the adverse effects of the theory's three risk factors. Findings support key predictions of the theory though some modifications to the model are indicated.