Examining Affect and Decision-Making in Relation to Suicide

Abstract

Suicide is one of the most tragic, costly, and perplexing of all human behaviors. Despite millennia of scholarly inquiry and a century of empirical research, we still do not know why people kill themselves. Thus, suicide remains a leading cause of death and burden. Ultimately, each person who attempts or dies by suicide must first make the decision to take their own life, meaning that they must select suicide over alternative options. One reason some people might select suicide is that they view suicide as a relatively good option for escaping extremely aversive contexts. One way to understand how people view an option’s goodness is to assess their affect toward it. In this dissertation I examined whether affect toward suicide differs between people with and without recent suicidal thoughts and behaviors (STB) and whether suicide information influences decision-making in an aversive context. In Study 1, we developed and evaluated a set of self-relevant suicide pictures depicting suicidal behavior from the participant’s own perspective in order to more validly assess affect and decision-making in relation suicide. Next, we examined explicit affect to these suicide pictures among people with and without STB. Study 1 findings suggest that the suicide pictures we developed are valid and reliable and, as hypothesized, people with STB find these pictures substantially more pleasant/less aversive than people without STB. In study 2, we examined implicit affect toward the suicide pictures among both adults and adolescents with and without STB. Study 2 findings suggest that implicit affect toward suicide is related to STB history; however, contrary to our hypothesis, suicidal participants did not display higher implicit positive affect toward suicide stimuli than nonsuicidal people. In study 3, we used the suicide pictures as cues in a decision-making task among people with and without STB, and we explored whether a computational model could capture latent decision-making biases within task behavior. Study 3 findings suggest that suicide pictures lead to poorer decision-making among suicidal, but not nonsuicidal, people when making decisions to escape an aversive context. Also, the computational model captured a decision-making bias related to the suicide pictures that helped distinguish suicidal from nonsuicidal participants over and above other strong predictors. Together, these findings suggest that suicidal people view and make decisions in relation to suicide differently than nonsuicidal people. Future studies, particularly those using longitudinal designs, are needed to better understand the directionality of these relationships and determine whether affect toward suicide predicts future STB. Better understanding the decision-making processes driving some people to select suicide could shed light on what we can do to help people select alternative options and, thereby, prevent suicide.