Suicidal Ideation and Interpersonal Needs: Factor Structure of a Short Version of the Interpersonal Needs Questionnaire in an At-Risk Military Sample.

OBJECTIVE: The interpersonal-psychological theory of suicide posits that perceived burdensomeness (PB; i.e., the belief that others would be better off if one were dead) and thwarted belongingness (TB; i.e., the belief that one lacks meaningful social connections) are both necessary risk factors for the development of suicidal ideation. To test these relations, measures are needed that are well validated, especially in samples of at-risk adults.

METHOD: The current study was designed to examine the factor structure of an eight-item version of the Interpersonal Needs Questionnaire (INQ) in a sample of 405 U.S. past and current military personnel (Mage  = 31.57 years, SD = 7.28; 90.4% male) who endorsed either current suicidal ideation and/or a past suicide attempt. Analyses were conducted using confirmatory factor analysis (CFA).

RESULTS: A bifactor model comprising a general factor, labeled interpersonal needs, and two specific factors, labeled PB and TB, fit the data best. The general factor captured a high proportion of overall variance (81.9%). In contrast, the TB factor captured only a modest amount of variance in items meant to capture this factor (59.1%) and the PB factor captured very little variance in items meant to capture this factor (13.5%). Further, only the interpersonal needs factor was associated with lifetime and past-week suicidal ideation as well as suicidal ideation frequency and duration.

CONCLUSIONS: The current findings indicate that, for the INQ-8 in high-risk military personnel, a general interpersonal needs factor accounted for the relations PB and TB share with suicidal ideation.