Clarifying the Pathway to Suicide: An examination of subtypes of suicidal behavior and their association with impulsiveness

Suicide is a leading cause of death around the world. Yet research seeking to uncover the causes of suicide has made little advancement. The purpose of this dissertation is to advance the understanding of one understudied but critical component of suicidal behaviors: how individuals move down the pathway from first thinking about suicide to ultimately attempting to take their own lives. A secondary goal of this work is to examine some flawed methods used in prior research in this area. This ancillary goal results in potential solutions provided in each paper that will allow researchers to collect more reliable data and to draw more valid inferences from these data to better understand the pathway to suicide. In Paper 1, I examine the validity of single-item measurement, a commonly used approach in this area of research in which key suicidal behaviors are assessed with one brief question. The primary finding in that paper is that single-item measurement is associated with significant misclassification of suicidal behavior. In addition, in that paper, I offer and examine an approach that improves validity for self-reported suicidal behaviors. In Paper 2, I attempt to improve on prior research examining suicide planning prior to a suicide attempt and present descriptive data showing how people transition from thinking about suicide to actually attempting (i.e. planning steps they take during this transition). This study revealed that the vast majority of steps occur within 2 weeks and most within 12 hours of an attempt. However, the results also revealed heterogeneous individual differences in the order and timing of planning steps as people moved from thinking about suicide to attempting suicide. In Paper 3, I examine the association between impulsiveness and suicidal behavior, using more comprehensive measures of both constructs than prior studies. Unlike most prior studies, this study also recruits groups that are able to test whether increased impulsiveness could help explain why, among people that think about suicide, some people attempt to kill themselves and others do not. In a secondary goal, I examine whether questions regarding past suicidal behaviors influence self-report measurement potentially causing invalid assessment. The findings from that paper reveal only one dimension of impulsiveness -- negative urgency -- that differs between suicidal and control participants and none that differ between ideators and attempters. Thus, dimensions of impulsiveness in Paper 3 do not appear to influence attempts among ideators. I also find that answering questions about suicide before self-report measures of impulsiveness influences the degree of impulsiveness reported by suicide attempters and suicide ideators. Specifically, attempters report increased levels impulsiveness compared with ideators when suicide questionnaires are asked first but there is no difference between the groups when participants' answer impulsiveness questionnaires prior to questions about suicide. In all three papers, I criticize prior research but provide approaches that could lead to modest improvements in methodology and, hopefully, lead to new discoveries in understanding how and why people transition from thinking about killing themselves to attempting suicide.