Do theories of suicide play well together? Integrating components of the hopelessness and interpersonal psychological theories of suicide.

Given that suicide is a leading cause of death worldwide, there has been considerable research on theories of suicide risk. Despite the volume of such research, each theory is largely investigated in isolation and there has been little attempt to integrate them. Thus, the goal of the present study is to integrate two theories of suicide risk, Alloy and Abramson's hopelessness theory of suicide (HT) and Joiner's interpersonal psychological theory of suicide (IPTS), into one mediational model where the effects of the risk associated with the HT variables (i.e., a negative cognitive style) on suicidal ideation are transmitted by the IPTS (i.e., perceived burdensomeness and thwarted belonging) variables. Participants were 245 young adults with elevated levels of depressive symptoms who completed self-report measures of suicide risk at baseline and a measure of suicidal ideation eight weeks later. The results of a mediated model supported our hypothesis. The effects of the HT variables on suicidal ideation were mediated by the IPTS variables. Furthermore, results did not support the reverse model, suggesting specificity of the direction of our hypotheses. These findings imply that there may be merit in attempting to integrate theories of suicide risk rather than studying them in isolation.