Explaining the association between suicidal desire and borderline personality disorder traits: A test of the three-step theory of suicide.

Abstract

The three-step theory of suicide (3ST) states that pain and hopelessness cause suicidal desire and that the extent to which pain exceeds connectedness determines the strength of suicidal desire. The ability of these premises to account for elevated suicidal desire in those with borderline personality disorder (BPD) traits was examined in 852 undergraduates oversampled for suicide risk (456 had histories of suicide ideation or attempts). Validated self-report questionnaires assessed BPD traits, current suicidal desire, psychological pain, hopelessness, and connectedness. Consistent with Step 1 of the 3ST, variance explained in suicidal desire by BPD traits was reduced from 16% to only 1% when controlling for pain and hopelessness. Consistent with Step 2, among those with suicidal desire, variance explained in the magnitude of that suicidal desire by BPD reduced from 6% to 0% when controlling for a pain-connectedness difference score. In a simpler model, controlling for pain, hopelessness, and connectedness reduced variance explained in suicidal desire by BPD from 16% to 0%. These findings suggest that the 3ST provides a useful lens to understand elevated suicidal desire in individuals with BPD and can inform suicide treatment and prevention strategies. (PsycInfo Database Record (c) 2026 APA, all rights reserved).