Cognitive and Interpersonal Vulnerability to Suicidal Ideation: A Weakest Link Approach

• Weakest link models focus on the most vulnerable component of a composite vulnerability.
• Although weakest link models are often applied to depression, they have not been studied in suicide.
• A weakest link model of suicidal ideation adds explanatory value to traditional composite models.

In contrast with traditional models of risk for suicidal ideation that combine multiple vulnerability components into one composite measure, weakest link perspectives posit that individuals are as vulnerable as their most vulnerable component (or “weakest link”). Such a perspective has been applied to depression, but has not been evaluated with respect to suicidal ideation. Thus, the goal of the present study was to apply a weakest link perspective to the study of suicidal ideation. We hypothesized that an individual’s “weakest link” among vulnerability components from the hopelessness theory (HT) and interpersonal psychological theory of suicide (IPTS) would interact with high levels of stress to predict increases in suicidal ideation over a 6-week period better than the traditional conceptualizations of HT or IPTS. Participants were 171 college students who completed measures of cognitive vulnerability, stress, and suicidal ideation twice over a period of 6 weeks. Bayesian regression analyses supported our hypotheses. The data fit the weakest link model using HT and IPTS components better than traditional conceptualizations of HT and IPTS. This study implies that weakest link models from depression may be useful in understanding which individuals are most vulnerable to experiencing suicidal ideation in the context of stress.