مدل معادلات ساختاری ترومای کودکی و استرس ادراک‌شده با سندرم پیش از قاعدگی: نقش میانجی ذهنی سازی عاطفه محور

Introduction
One of the important problems that affects the functioning of some women is premenstrual syndrome. Women with this syndrome have physical, emotional, and behavioral symptoms and experience these symptoms around the time of menstruation. Neurotransmitters such as serotonin and GABA are believed to play an important role in PMS symptoms. Based on studies conducted in Iran, the prevalence of this syndrome is estimated at 41.5%. In the etiology of this syndrome, several environmental factors, such as childhood trauma, can be mentioned. In general, traumas are life-threatening events and leave lasting adverse effects on a person's life. Another possible factor related to premenstrual syndrome is perceived stress. Based on the studies conducted, it seems that a variable can play a role as a mediator in the relationship between childhood traumas and premenstrual syndrome, and affective mentalization can likely play a mediating role in this. The affective mentalization variable is a concept used by Jurist (2005, 2018) in emotion regulation. According to the investigations carried out, fewer studies have been conducted in this field in Iran, so the present study aims to investigate the structural equation model of childhood trauma and perceived stress with premenstrual syndrome and the mediating role of affective mentalization.
Method
The present study is a descriptive modeling study. In the present study, 260 students from Tehran, Karaj, and Urmia were selected through convenience sampling. These individuals responded to questionnaires on the Childhood Trauma Questionnaire (CTQ-28) from Bernstein et al. (1994), Brief Perceived Stress Scale (BPSS) from Cohen et al. (1983), Premenstrual Symptoms Screening Tool (PSST), and Brief-Mentalized Affectivity Scale (B-MAS) from Greenberg et al. (2017). The reliability of the questionnaires in the present study was determined using Cronbach's alpha method, and their values were within an acceptable range. Female students from Tehran, Karaj, and Urmia universities, with a history of at least one symptom of premenstrual syndrome, access to the Internet, and a willingness to participate in the study, were included. And people who did not meet the inclusion criteria mentioned in the study were excluded from the study. The present study was conducted online; the link containing the content of the questionnaires was made available to students in cyberspace, and the participants participated in the study voluntarily and with informed consent. The principles of the Declaration of Helsinki were observed in conducting the study. The data of this study were analyzed using the structural equation modeling method and PLS-3 software.
Results
In the present study, 260 female students were surveyed (mean: 23.76, standard deviation: 5.191). Using analyses conducted with the Kolmogorov-Smirnov test and skewness and kurtosis, the data were not normal, so the partial least squares method (PLS-3) was used to analyze the data. The results of the divergent validity using the Fornell-Larcker criterion showed that the diagonal values were larger than the off-diagonal values, and the Heterotrait-Monotrait ratio of correlations (HTMT) ranged from 0.286 to 0.678, indicating that these values are within an acceptable range. The goodness of fit (GOF) method was used to fit the model, and the results showed that the model had a good fit (0.252). The composite reliability (CR) of the research variables was higher than 0.7, indicating that the variables have a desirable reliability, and the average variance extracted (AVE) values were also greater than 0.5, indicating that they were within an acceptable range. Considering that the quality values of the structural model, as measured by the CV-Red redundancy validity index, were higher than zero, the results indicated that the model possessed desirable structural quality and predictive ability. To ensure that there was no collinearity problem between independent variables, the VIF index was calculated, and in the present study, the index values were within an acceptable range (1.256 to 2.270). In general, the results of the effects of the research variables showed that there is a positive and significant relationship between childhood trauma and premenstrual syndrome (β = 0.225) and between perceived stress and premenstrual syndrome (β = 0.620). There is a negative and significant relationship between childhood trauma and affective mentalization (β = -0.215), between perceived stress and affective mentalization (β = -0.325), and between affective mentalization and premenstrual syndrome (β = -0.743). Therefore, affective mentalization plays a mediating role in the relationship between childhood trauma and perceived stress with premenstrual syndrome.
Conclusion
According to the results, there is a positive and significant relationship between childhood trauma and premenstrual syndrome. Childhood trauma can have a wide range of effects on women's well-being, from how it affects the timing of puberty to the severity of premenstrual syndrome symptoms. Based on other results, there is a positive and significant relationship between perceived stress and premenstrual syndrome; it seems that stress and premenstrual syndrome have reciprocal effects. So that changes in hormonal levels during the menstrual cycle affect sensitivity to stress, and high levels of stress also affect different levels of hormones. Other research results showed that affective mentalization plays a mediating role in the relationship between childhood trauma and premenstrual syndrome. Childhood trauma affects the brain and makes people have difficulty regulating emotions, increasing the likelihood of developing disorders such as premenstrual syndrome. Other research results showed that affective mentalization plays a mediating role in the relationship between perceived stress and premenstrual syndrome. Stress and the physiological changes of women before menstruation have reciprocal and mutual effects on each other. In fact, stress can affect a person's emotional regulation and ultimately lead to the development or even exacerbation of symptoms of premenstrual syndrome. Also, the physiological changes of women before menstruation affect the stress response.
Ethical Considerations
Compliance with ethical guidelines
The principles of the Declaration of Helsinki were observed in conducting this study. Participants were told that participation in the study was voluntary and that confidentiality would be respected.
Funding
No funding was received for this research.
Authors contribution
FDM was the main investigator and wrote the first draft of the manuscript. ES supervised the study, and MR contributed to the study design. All authors read and approved the final manuscript.

Conflict of interest
There is no conflict of interest in this study.
Acknowledgments
The authors of this study are grateful to all participants in the study.