An Examination of the Interpersonal-Psychological Theory of Suicide among Urban Firefighters: Associations with Posttraumatic Stress and Distress Tolerance

Firefighters report an alarmingly high rate of suicidal ideation, behavior, and attempts. Due to the inherently stressful occupational demands of the job, firefighters also report high rates of trauma exposure and posttraumatic stress disorder (PTSD) symptomatology, which may pose increased risk for the development of suicidality (i.e., ideation, behavior, and risk). Distress tolerance (DT), defined as the perceived (i.e., self-report) or actual/behaviorally-indexed (e.g., computer tasks, cold pressor) ability to tolerate negative or aversive emotional problems or physical states, is a potentially important cognitive mechanism to consider in relation to suicidality and PTSD among firefighters. The overarching goal of the current study was to examine the associations between PTSD, DT, and suicidality in context of the Interpersonal-Psychological Theory of Suicide (IPTS) framework among a sample of firefighters. Participants were comprised of 248 trauma-exposed firefighters (Mage = 40.23 [9.58]; 91.9% male) who completed a web-based questionnaire battery. Preliminary analyses included descriptive statistics and bivariate correlations for all pertinent study variables, and remaining analyses utilized SPSS PROCESS MACRO to conduct moderated mediation analyses. Results revealed that thwarted belongingness (TB) significantly mediated the association between PTSD symptom severity and suicide ideation severity. There was also a significant and positive interactive effect between PTSD symptom severity and perceived emotional DT in relation to TB at moderate and high levels of perceived emotional DT. The mediating effect of TB in relation to PTSD symptom severity and suicide ideation severity was conditional on moderate and high levels of perceived emotional DT. Moreover, there was a significant and positive interactive effect between capability for suicide and TB in relation to global suicide risk at high levels of TB. This is the first study to examine associations between PTSD, DT, and suicidality within the context of the IPTS among firefighters. Findings highlight unique associations among suicide risk variables and hold important clinical implications for firefighters, such that perceptions of TB might be an especially potent risk factor for the development of subsequent suicidal ideation and behaviors for this particular population. Results may be used to inform suicide prevention and peer support programs among departments nation-wide.