Psychological Assessment28.12 (Dec 2016): 1684-1694. Joiner’s (2005) interpersonal-psychological theory of suicide (IPTS) has become one of the most frequently studied in the field. Currently there are 2 primary measures designed to assess the 3 main constructs of the theory—the Interpersonal Needs Questionnaire (INQ; Van Orden, Witte, Gordon, Bender, & Joiner, 2008) and the Acquired Capability for Suicide Scale (ACSS; Van Orden et al., 2008). The psychometric properties of these 2 measures were evaluated in a sample of 477 U.S. military veterans. To read the full article, log in using your NHS OpenAthens details.