The aim of the current study was to validate the Interpersonal Needs Questionnaire (INQ-15) and to test its reliability in Persian-speaking Iranian undergraduate students. In this cross-sectional study, 485 undergraduate students (age: 20.66 ± 1.42, 60% female) were assessed on the two subscales of perceived burdensomeness (PB) and thwarted belongingness (TB) and the Suicide Behavior Questionnaire-Revised (SBQ-R). Exploratory structural equation modelling (ESEM) confirmed the construct validity of INQ-14, excluding INQ#9. In addition, INQ#8, articulated in an equivalent Persian phrasing, loaded well on TB. The measurement model tested by confirmatory factor analysis (CFA) suggested INQ#11 to be eliminated, resulting in INQ-13-P to consist of PB and TB-7. The internal consistency and convergent/discriminant validity were established. The concurrent validity of PB was solidly established in terms of past year suicidal ideation (PY-SI) above and beyond anxiety, depression, prior suicidality, and TB-7. The effect of PB on PY-SI was stronger, where prior suicidality had already occurred or the perceived likelihood of future suicide (PLFS) was high. Moreover, TB-7 could only indicate PY-SI, where prior suicidality had already occurred or PLFS was high, albeit when PB was omitted. The interaction term was significant; however, beyond anxiety and depression, the effect of TB-7 on PY-SI was significant where PB was very high (n = 40, 8.25%). Therefore, future studies can utilize INQ-13-P as a valid and reliable instrument in Persian-speaking populations. However, further studies should examine the construct validity of TB and its relationship with suicide ideation in different populations.
Keywords: Interpersonal Needs Questionnaire; perceived burdensomeness; psychometrics; suicide; thwarted belongingness; young people.
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