An investigation of interpersonal-psychological variables in air force suicides: a controlled-comparison study

Joiner's (2005) theory attributes suicide to an individual's acquired capability to enact self-harm, perceived burdensomeness, and thwarted belongingness. This study evaluated whether Joiner's theory could differentiate United States (US) Air Force (AF) personnel (n = 60) who died by suicide from a living active duty AF personnel comparison sample (n = 122). Responses from AF personnel on several scales assessing Joiner's constructs were compared to data from a random sample of postmortem investigatory files of AF personnel who died by suicide between 1996-2006. This research also introduced a newly designed measure, the Interpersonal-Psychological Survey (IPS), designed to assess the three components of Joiner's theory in one, easy-to-administer instrument. Analyses of the psychometric properties of the IPS support initial validation efforts to establish this scale as a predictive measure for suicide. Findings support that one's score on the Acquired Capability to Commit Suicide subscale of the IPS and the IPS overall score reliably distinguished between the two groups. The implications of these findings in relation to suicide prevention efforts in the US military are discussed.