||This dissertation explores the effects of early-life parental death upon an offspring's later-life risk of suicide, major depression and substance abuse. By situating the question within a biopsychosocial life-course framework, we find that this association may lead to secondary stressors, be moderated by familial vulnerabilities, and occur in tandem with other early-life stressors. The study offers innovative, creative, and substantial contributions to the current literature on early parental death and later behavioral health by (1) disentangling social from biological mechanisms by using remarriage of surviving parent as a proxy for social integration, (2) testing for differential vulnerability by investigating the moderating effects of familial suicide history, and (3) constructing and testing the influence of a new measure called the Utah demographic childhood adverse exposures (DECADE) scale. The findings suggest that early-life stress, especially parental death, may impact later-life behavioral health, and the association is moderated by other contextual factors. The dissertation further demonstrates the utility of demographic pedigree databases for transdisciplinary studies of behavioral health, and proposes innovative quantitative measurements that might be utilized for future life-course studies.