1. Introduction
There are three operational definitions for resilience: 1. Resilience as a personality trait; 2. Resilience as a positive mental health (such as positive perception, self-concept, academic achievement, success at tasks, etc.) or the absence of mental illness in spite of exposure to risk; 3. Resilience as a dynamic process that results from the interaction of individual and contextual variables which evolves over time. This definition is more important due to the integration of individual contextual variables of resilience [11]. People with psychological hardiness and sense of coherence not only do not see problems as obstacles in their way, but they can transform risky conditions into a opportunity for growth. Resilience and hardiness are therefore closely related to each other. According to the second definition, resilience and mental health are closely linked to each other. In other words, only those with a minimum mental health can be resilient in critical situations. Therefore, three variables of resilience, hardiness and mental health are interconnected.
Resilience refers to the factors and processes that cross the line of "problematic behaviors risk/psychological harm" and lead to adaptive consequences in adverse conditions. Positive adaptation to life can be either a outcome of resilience or as a precursor for a higher level of resilience. This is due to the complexity of definition and the process of resilience [12]. 
One of the most common responses to adverse and critical situations is anger whose main purpose is to reduce emotional stress, regardless of its future consequences. Obviously, anger behaviors are only for eliminating and hitting the source of frustration, and have no plan or perspective to resolve the problem. Therefore, resilience in critical situations and anger in failure conditions can be considered as two opposing reactions, and by increasing one of them, the other can be reduced, which was tested in the present study.To our knowledge, there is no study on the effect of anger control on three resilience, hardiness and general health among school students. In this regard, the present study aimed to evaluate the effect of a anger control training program on resilience, hardiness and general health of female school students.
2. Methods
This is a quasi-experimental study with pre-test, post-test, follow-up design using control group. The study population consisted of all female students of technical and vocational schools in Tehran, Iran (district 13) in 2017. For sampling, one school was selected from the 13th district, which had 80 female students. Then, using the Morgan table, 60 subjects were selected and randomly assigned into two groups of intervention (n=40) and control (n=20). The intervention groups received anger control training program for 12 weeks, one session per week. To collect the data in all three stages of pretest, post-test and 3-month follow-up, four questionnaires State-Trait Anger Expression Inventory-2 (STAXI-2), Connor-Davidson Resilience Scale, Kobasa’s Hardiness Scale, 28-item General Health Questionnaire (GHQ-28) were used. The collected data were analyzed in SPSS v.24 software using repeated measures ANOVA.
3. Results
The mean age of participants was 16.86±0.945 years (aged 15-18 years). Their Grade Point Average (GPA) was in a range of 14.72-19.93 (Mean GPA=18.74±1.037). In assessing the normality assumption, the results of Kolmogorov-Smirnov test showed that the scores of all subscales were distributed normally. The results of Box’s test showed that the homogeneity of variance-covariance for all three variables was met. The assumption of the equality of variances using the Levene’s test was also confirmed. Then, the repeated measures ANOVA was carried out three times consecutively and the results showed a significant difference. The results of Mauchly’s test for the resilience variable showed the sphericity of the variance-covariance matrix at the significance level of 0.05 (P=0.536). Therefore, its correction test was used for measurement at 3 phases and to evaluate the within-subject effects. The results showed a significant difference in the scores between the three measurement phases (P<0.05). The interaction effect of time (pre-test, post-test and follow-up) and group was also significant (P<0.05). These results indicate that group anger-control training was effective in increasing the resilience level of students.
The results of the Mauchly’s test for hardiness variables (P=0.019) and general health (P=0.034) rejected the assumption of the sphericity of the variance-covariance matrix, and therefore, Greenhouse–Geisser correction test was used for measurement at 3 phases and to evaluate the within-subject effects. The results reported a significant difference in the scores between the three measurement phases (P<0.05), and the interaction effect of time (pre-test, post-test and follow-up) and group on hardiness and general health was also significant (P<0.05). These results indicate that group anger-control training is effective in increasing the hardiness and general health levels of students.
4. Discuss and Conclusion
The results this study showed that the anger control training program increases the resilience, hardiness and general health levels of female school students. The mean pre-test, post-test and follow-up scores of students in resilience, hardiness and general health showed that their mean post-test and follow-up scores were higher than their mean pre-test scores. There mean difference was significant which indicates the effect of the anger control training program on resilience, hardiness and general health of students. Based on the educational contents presented in the training sessions in this study, it can be expected that the use of behavioral strategies such as assertiveness and improving relationships and increasing self-esteem as well as strategies such as relaxation that affects the physical symptoms resulted from anger and create a sense of relaxation, can reduce anxiety and worry in the person. On the other hand, cognitive strategies such as problem-solving, knowledge of cognitive errors, fighting with negative thoughts, logical thinking and the use of positive self-talk can changes the attitudes, and which led to the effectiveness of presented program.
Anger control skill training is a compensatory measure against risk factors and increases the resilience of a person in facing with dangerous and challenging situations. It is one of many ways to promote resilience in many ways. On the one hand, it increases individual capital, and on the other hand, it enhances the quality of communication between individuals by influencing social relationships. According to the findings of this research, it can be said that increased resilience in students due to receiving the anger control training courses was considerable, but its increase also depends on the other factors.
The findings of this study on the increase of hardiness and general health in students through group anger-control training is consistent with the results of other similar studies, confirming that the presented program, due to certain components presented to the students during the period can increase the hardiness and eventually their general health.
Ethical Considerations
Compliance with ethical guidelines
A written consent was taken from the subjects to participate in the research. They were free to leave the test whenever they want.
Funding
The article is taken from the MA. thesis of first author in Department of Psychology, Faculty of xHumanities, Electronic Branch, Islamic Azad University, Tehran.
Authors contributions
All authors contributed equally in preparing all parts of the research.
Conflicts of interest
The authors declared no conflict of interest.