The Big Five Inventory (BFI) is one of the most widely used personality questionnaires, but very few studies have been conducted on its psychometric properties in Iranian population. This study was carried out with the aim of studying the psychometric properties of the BFI questionnaire. For this purpose, 390 university students in Tehran (210 girls and 180 boys) with an age range of 18 to 56 years (M = 27.52; SD = 8.79) were selected using the convenience sampling method and completed BFI and NEO-FFI questionnaires. Cronbach's alpha, multitrait-multimethod matrix, and confirmatory factor analysis were used to estimate the psychometric properties of the questionnaire. The result of the confirmatory factor analysis showed that 15 of the 44 items did not have a strong factor loading (higher than 0.40) on the corresponding factors and were therefore removed from the questionnaire. The fit indices showed that the Persian version of 29 questions (BFI-29) with 5 factors has a good fit with the data. The reliability analysis also showed that the range of Cronbach's alpha coefficients of the factors is from 0.70 to 0.79. The lowest Cronbach's alpha coefficient was related to agreeableness factor and the highest was related to conscientiousness. The findings from the multitrait-multimethod matrix showed that the BFI-29 questionnaire has good convergent and divergent validity with the NEO-FFI questionnaire. In general, based on the results of the present study, it can be said that the BFI-29 questionnaire has desirable psychometric properties and whenever a short tool for personality measurement is needed, this questionnaire can be used.

Background: Addiction is one of the most prominent problems and the fourth leading crisis worldwide. In Iran, this issue is more complicated because of increasing young population in this country. Objectives: This study aimed to predict addiction susceptibility regarding students’ personality traits at Qazvin universities. Methods: In this cross-sectional study, 227 students from Qazvin universities were selected using the multistage random stratifi ed sampling method. Data collection tools were demographic information form, Addiction Susceptibility questionnaire (ASQ), and NEO personality inventory. After collecting the required data, SPSS software version 21 was used to analyze the data by running variance analysis and paired sample t-test. Results: In this study, neuroticism (P = 0. 031) and openness (P = 0. 043) with regression coeffi cients of 0. 584 and 0. 586 had positive and signifi cant eff ects on addiction susceptibility, respectively. In contrast, extraversion (P = 0. 023), agreeableness (P = 0. 038), and consciousness (P < 0. 001) with regression coeffi cients of-0. 639,-0. 186, and-1. 342 had negative and signifi cant eff ects on addiction susceptibility, respectively. Conclusions: The fi ndings revealed a signifi cant relationship between personality traits and addiction susceptibility. Accordingly, the aforementioned psychological traits must be empathized in educational, preventive, and therapeutic programs so that the vulnerable groups, including students, would receive some help.

For studying validity and reliability of GARDOON Personality Questionnaire (Farahani et.al.2004), 2400 girls and boys students in different educational regions in Tehran, completed the 126 revised GARDOON Personality Questionnaire. The promax rotation factor analysis on boys group indicated the 5 principal components as Openness to experience, Neuroticism, Extraversion, Conscientiousness and Religiousness, and Agreeableness. The conformity factor analysis on girls showed the same results. The reliability of GARDOON for girls and boys were acceptable.