Evaluating the interpersonal theory of suicide among post-9/11 veterans: Suicidal desire and intent in the early transition to civilian life

Relative to the civilian population, veterans are at elevated risk of dying by suicide. However, there have been few studies using the interpersonal theory of suicide (ITS) to help explain their excess suicide desire (SD). ITS posits that the desire/intent to die by suicide occurs when two risk factors are present - thwarted belongingness (TB) and perceived burdensomeness (PB). A large cohort of post-9/11 veterans were surveyed approximately every six months over several years, beginning soon after transitioning to civilian life. Stable trait-like perceived burdensomeness (T-PB) and stable trait-like passive suicidal ideation (T-PSI) were positively associated with suicide risk (SR), while trait-like thwarted belongingness (T-TB) was not. T-TB predicted subsequent T-TB and T-PB predicted subsequent T-PB over time. T-PSI predicted subsequent T-PSI over time. T-TB inconsistently predicted T-PSI over time, while T-TB predicted T-PSI at all waves with one exception. Thus, there was partial support for ITS with T-PB and T-PSI more highly predictive of SR than T-TB. Temporal state-like perceived burdensomeness (S-PB) and temporal state-like thwarted belongingness (S-TB) were inconsistently associated with temporal state-like passive suicidal ideation (S-PSI). Several study limitations are described, including the use of validated but indirect measures of relevant ITS constructs.