According to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), exposure to the threat of death, sexual violence or serious injury is called a traumatic event, which can be direct or indirect [1]. Using the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria, the prevalence of lifetime traumatic event exposure among US adults has been estimated to be roughly 90% [2], including disasters, chronic illnesses, vehicle accidents, and loss of family members. These events exert different psychological effects on the exposed people, including negative impacts such as post traumatic stress disorder (PTSD), as well as positive effects. The positive effects are defined as post traumatic growth (PTG) [3]. About 30-90% of people who have experienced a traumatic event in their life have reported at least one form of PTG [4]. The different traumatic events have a different impact on PTG; people with severe trauma report more benefits and chronic events could be very different from acute events in their psychological effects [5].

In general, PTG refers to positive psychological changes and greater growth than the pre-crisis level of performance, which, through cognitive reconstruction, makes the person adapt to the new reality [6]. Positive changes following injury occur in five aspects: “Recognizing Personal Strength” occurs when a person feels more confident. “Finding Unknown Possibilities and Opportunities” is experienced when people find a new way of life that would not be available if they did not experience a traumatic event in life. The domain of “Experiencing Positive Changes in Relationships” that shows a sense of kindness or closeness to others. “Appreciation of life” seems to have more appreciation for each new day of life. And finally, the scope of “Spiritual and Existential Change” understands personal growth that has a much better understanding of spiritual issues [7-9].

The positive experiences of traumatic events lead to a more productive life, having more life satisfaction in comparison with the pre-traumatic life [10-12].

The measurement of PTG is the most important task in the field of growth due to capturing the phenomenon of positive effect. Subsequently, comprehensive and validated tools have been proposed to measure and compare PTG [13]. Different scales have been designed to measure PTG, such as the Stress-Related Growth Scale (SRGS) [14], the Benefit Finding Scale (BFS) [15], and the post traumatic Growth Inventory (PTGI) [5].

Among them, the PTGI scale is the most commonly used tool in the literature. It consists of 21 self-report questions on five subscales [5]. A short form of the PTGI (PTGI-SF) was developed by Cann et al. [16] and presents a reasonably short measure, and its use has recently expanded [17]. The PTGI-SF is employed as it saves time and energy and is easy to use by people who are willing to participate in studies but are very busy. The need for short measures is undeniable where research involves people who have little physical energy (such as patients), there is limited data collection time and conditions for filling in questionnaires (e.g., in wars), and there is little time and response rate (e.g., for people who are deeply involved in crises), and when multiple questionnaires should be completed. The approved PTGI-SF contains 10 items, including five subscales, which are also available in the original version (Appendix) [16].

So far, the PTGI-SF has been translated into several languages, including Spanish [17], Italian [18], Chilean [19], Arabic [20], and Urdu [21].

Iran has experienced many disasters and is still at risk of disasters [22]. This country is geographically located in a region most prone to natural disasters and with a history of repeated earthquakes, droughts, floods, hurricanes, epidemics, and fires [23]. In addition, there have been numerous man-made disasters in the country, such as the eight-year Iraq war imposed on Iran with a high prevalence of catastrophic chemical attacks (acid throwing) [24, 25], the PLASCO Tower collapse [26], road traffic injuries [27], etc. Besides, there are many chronic diseases such as diabetes and cardiovascular diseases with a high prevalence among Iranian adults [28]. The expression of PTG can be dependent on cultural conditions [29]. Weiss and Berger [30]also emphasized the importance of monitoring post traumatic growth in different languages and cultural environments to guide practitioners in helping those at risk of traumatic events. The culture of Iran may increase one's ability to cope with traumatic events, with patience in the face of suffering and crisis highlighted in the Iranian historical literature, especially in poetry [31]. Additionally, the Islamic beliefs of the majority of Iranian people adapted from the Islamic holy books emphasize the opportunities for growth after being challenged with a crisis [32]. Therefore, this study evaluated the psychometric properties of the Persian-translated post traumatic Growth Inventory-Short Form (PTGI-SF) in Iran.

The correlations between the questions in the range of 0.17 to 0.57 and the descriptive statistics of the scale, including means, standard deviations, skewness, and kurtosis, are presented in Table 1. The CFA confirmed the five factors (Figure 1) with all fit indices, indicating an adequate fit (chi-square=72.17 on 25 degrees of freedom, CFI=0.981, TLI=0.955, RMSEA=0.055, and SRMR=0.029). The factor loadings ranged from 0.57 to 0.82. Inter-correlations between the dimensions were significant and high (range between .54 and .91). The PTGI-SF shows a reliability coefficient of .86 for all the items. The reliabilities of the dimensions ranged between 0.57 for relating to others (D1) to 0.76 for spiritual change (D4) (Table 2).

Fig. (1). Factor loadings from CFA of PTGI-SF.

In addition, Table 2 presents the correlations between PTGI-SF dimensions and the Persian version of the DUREL. All the scale dimensions were moderately associated with DUREL. The non-significant Δχ2 and very small changes in CFI, TLI, and RMSEA for each succeeding invariance model showed the establishment of measurement invariance for gender in three levels of configural, metric, and scalar (Table 3). ΔCFI was uniformly <.01 and ΔRMSEA was uniformly <0.05 for every level of invariance across genders.

As Cann et al. [16] demonstrated, in critical situations where individuals are unable to respond due to time and energy restriction, the PTGI-SF form can be employed. Weiss and Berger reported that PTG monitoring in linguistic and cultural settings is necessary for guiding practitioners to accompany people exposed to stressful events [30]. Therefore, the need for such a questionnaire in the Iranian research literature is well understood, and the present study found that the Persian version of the PTGI-SH questionnaire has acceptable psychometric properties, considering the results of CFA, model fits, measurement invariance, and Cronbach’s alpha.

CFA confirmed five factors, and all the goodness-of-fit indices were acceptable and approved the satisfactory model fit [41]. The outcome of this result is similar to the original questionnaire [16], in which the number of factors is five. This factor structure coincides with the study b Tedeschi and Calhoun [5] and is in line with the findings of other studies that have performed CFA for PTGI-SF [18-20, 42]. The results also showed that the item factor loading of all the items was higher than the minimum 0.50, and this was a convergent validity confirmation [43]. Therefore, inter-correlations between domains were in the range of moderate to strong relationships, and there was almost no multicollinearity, suggesting that the five domains of positive change have acceptable reliability. As shown in Table 2, the Cronbach’s alpha had 10 questions in the acceptable range, although two of the five dimensions were <0.7 due to the small number of items (two items) for each field [44]. The overall PTGI-SF score was high, and these findings are comparable to other findings in the literature [16, 19, 20].

The correlation coefficient of the PTGI and DUREL questionnaire was higher than the minimum acceptable level of 0.4 [45], which was in favor of the concurrent validity of the questionnaire. According to previous studies, there is a significant relationship between religious beliefs and PTGI [35], which also provides evidence to support the idea that religious beliefs are useful in catalyzing the process of PTGI [35, 45].

An important point in the evaluation of construct is to test if the questionnaire yields different results for different backgrounds and groups of people; if this happens, it may be an indication of the measurement of bias [46]. Establishing the measurement invariance implies the equivalence of rating in the two sexes, indicating that the results of this questionnaire are generalizable across genders [47].

Our study had two limitations. Firstly, we could not use a longitudinal framework, and instead adopted a cross-sectional design. It is, therefore, recommended that future studies evaluate growth at several time points to assess the temporal stability of the measurements [13]. Secondly, 20% of the participants were illiterate; therefore, the researchers had to complete the questionnaires through interviews with them. Given the high risk of natural disasters in Iran, as well as other traumatic events, this tool can be employed as a short-term measure in post-disaster assessments.

The Persian version of PTGI-SH proved to have good reliability and validity for assessing posttraumatic growth, and can be employed in future research. These results contribute to the growth of research on traumatic growth in diverse cultures and subcultures.