The Development and Validation of the Thwarted Belongingness Scale (TBS) for Interpersonal Suicide Risk

Thwarted belongingness (TB) has been identified as a risk factor for the development of suicide ideation. However, measures for assessing this construct are currently limited. The present study aimed to develop and validate a new self-report measure for thwarted belongingness (TBS) against the Interpersonal Needs Questionnaire Thwarted Belongingness sub-scale (INQ TB; Van Orden et al. 2012), and provide a comparative test of the Interpersonal Psychological Theory of Suicide (IPTS; Joiner 2005). A 42-item pool underwent refinement via three consecutive stages: (1) expert feedback, (2) item selection study using a sample of community-dwelling Australian adults (Study 1, N = 284), and (3) validation study and test of IPTS predictions in a larger sample of community-dwelling Australian adults (Study 2, N = 747). Exploratory and confirmatory factor analyses supported the uni-dimensionality of the TBS. Item response theory analysis indicated that the TBS captured more information over a slightly narrower range than the INQ TB. Preliminary support was provided for the IPTS ideation prediction when using the TBS and INQ TB. The TBS may provide enhanced identification of TB in individuals who display moderate to high levels of this interpersonal risk factor. However, further development of additional interpersonal measures is needed to ascertain the role of TB in relation to interpersonal suicide risk and how to best approach its conceptualisation and measurement.