Emotion-related impulsivity factors and intolerance of uncertainty are uniquely associated with interpersonal-psychological risk factors for suicide.

Objectives: The interpersonal-psychological theory of suicide identifies three risk factors for suicidal behaviours: perceived burdensomeness, thwarted belongingness, and acquired capability. We sought to clarify relationships between the interpersonal-psychological risk factors and two individual difference factors, emotion-related impulsivity (ERI) and intolerance of uncertainty (IU).

Methods: In the current study, we analysed self-report scales from a large community sample (N = 169) that was oversampled for individuals with elevated suicidality. We considered two separate factors of ERI: Pervasive Influence of Feelings, which measures how much a person's emotions shape their worldview, and Feelings Trigger Action, which measures impulsive behavioural reactivity to emotions. We tested unique effects of ERI and IU and the interactions of ERI × IU on the three interpersonal-psychological risk factors using linear regression models.

Results: Pervasive Influence of Feelings correlated with higher perceived burdensomeness and thwarted belongingness, whereas Feelings Trigger Action correlated with higher perceived burdensomeness and acquired capability. Within the regression models, IU correlated significantly with lower acquired capability but not perceived burdensomeness or thwarted belongingness. Interactions of ERI × IU were not significant.

Conclusions: These results demonstrate the importance of considering both factors of ERI in understanding the risk for suicide. Our results also provide novel evidence that while IU may not impact risk factors such as perceived burdensomeness and thwarted belongingness, higher levels of IU may serve as some protection against individuals' acquired capability for suicidal action. Limitations and implications of findings are discussed.