Abstract
BACKGROUND: Existential anxiety is the anxiety that goes beyond objective threats and is related to a person's existence. Due to the lack of appropriate instrument to measure all five domains of existential anxiety in the Iranian population, this study aimed to examine the psychometric properties of the Existential Concern Questionnaire (ECQ) in the Iranian general population. METHODS: This online cross-sectional survey was conducted from October 9 to December 11, 2023 in Tehran, Iran. We used an Internet-based data collection method. A total of 549 participants completed the questionnaires. The research instruments included the Existential Concern Questionnaire, Existential Anxiety Questionnaire, Meaning in Life Questionnaire, Short version of the Beck Depression Inventory, Intolerance of Uncertainty Scale-12, and Death Attitude Profile Revised. Confirmatory factor analysis, convergent validity, and concurrent validity were used to measure the validity of ECQ. Cronbach's alpha and split-half methods were employed to assess the reliability of the ECQ. RESULTS: Confirmatory factor analysis showed a good fit of the unidimensional model (CMIN/DF: 2.802, RMR: 0.066, GFI: 0.914, NFI: 0.911, CFI: 0.941, PNFI: 0.769, PCFI: 0.794, RMSEA: 0.057). Also, the correlation of ECQ with other variables was as expected except for the search for meaning in life (r: 0.010, P = 0.808), which indicates the validity of this questionnaire. The reliability of the questionnaire was also acceptable (Cronbach's Alpha: 0.935). CONCLUSIONS: The results supported the validity and reliability of the ECQ. The mentioned questionnaire can be used in Iranian general population. Considering the importance of existential anxiety in etiology of some disorders, it is suggested that the future studies focus on validation of the ECQ in different clinical samples and cultures.