Anger is a natural and original emotion in human. It followed by aggressive behaviors and irreparable consequences, if it is not controlled. Therefor many studies have been done in this regard that show several contributing factors in anger including frustration [1], discrimination, social and financial problems and occupational stresses [2].

As nursing is one of the most stressful jobs encountering with high levels of stress, national association for occupational safety of America has introduced it as the most stressful job [3]. Nurses encounter more aggressive situations than other health staffs because of more communications with patients and their relatives [4]. It can increase their aggression [5]. Long term experiencing negative emotions, age, marital status, length of working experience, interpersonal relationship [6-8], working above 40 hours during the week, risky conditions and characteristics of patients [9] can cause different levels of aggression in nurses. Accordingly working in accidents and emergency [10] and psychiatry wards [11, 12] may provide setting for experiencing high levels of job stress and predispose nurses to aggressive behaviors. Aggression may also be seen as externally driven which culturally is called “learned” aggression and the strongest correlation has been found between current violence and previous manifestations thereof. Accordingly, aggression is related to mechanisms that have further taken in terms of “perceived acquirement failure” theory, based on that, aggression is highly connected to the role of the state and the manifestation of powerlessness and is placed in a broad socio - economic context [13].

Nurses’ aggression has also unpleasant consequences for patients, their family and health care system [14]. It may disturb their interpersonal relationships and decrease their job satisfaction [15, 16] as one of the most important effective factors on declining the quality and working efficiency in nurses [17, 18] and the main factor of turnover in different countries’ nursing system [19-21]. Job satisfaction is affected by various factors including working condition, communication skills [22], salary, type of hospital or the ward working in [23], age, marital status, recruitment status [24], emotional intelligence [25] and occupational stress [26]. Recent studies illustrate that occupational stress that is closely related to aggression, job satisfaction and turnover [26] is highly influenced by coping strategies and it is recommended to pay more attention to nurses’ coping strategies which is effective on their health state and quality of nursing care [27]. Findings also demonstrated that the kind of coping strategy which is used, influences significantly the control of anger and aggression [28].

So, lack of anger-management skill on one hand may result to continuous tension experience in working environment [14] and on the other hand may cause repeating relational problems with patients and their relatives, negative effects on physical and mental health and reducing job satisfaction [29].

Related researches have earned considerable level of job dissatisfaction (between 54 to 64 percent) among nurses [18, 30] and that neglecting their job satisfaction in long term might result to commitment reduction [31], absence from work and making disturbance in organization’s system at the organizational level [18] so that abandon this profession by nurses in recent years has become a worldwide problem so that one third of the UK nurses and one fifth of the USA nurses tended to leave this occupation [32].

According to a review of meta - analyses, cognitive - behavioral interventions have shown more consistent results for both anger and aggression in related to aggression treatment [33]. Other findings have also shown that cognitive - behavioral intervention improves attitude, increases anger - management knowledge and skill in different groups including students, tennis players and nurses [34-38] and the most impressive interventions are cognitive restructuring along with relaxation and regular unconditioning. These studies emphasize the necessity of existing cognitive - behavioral interventions among anger - management interventions [39].

Lack of preparation by mandatory violence prevention training is one of the main experiences perceived and reported by nurses [40]. Many researches have also shown that nurses’ aggression and job satisfaction in psychiatric wards are highly influenced by occupational stress [12, 14], risky conditions and relational problems [9] and emphasized the importance of skills training previously. Anger expression would cause many damages for nurses, their family and health care system. However there are not considerable studies in this regard. The present study was done with the aim of investigating the effectiveness of cognitive-behavioral anger - management training on aggression and job satisfaction among nurses in psychiatric hospital.

The present study is a semi - experimental research with pretest - posttest control group design. Population of the study included all nurses working in a psychiatric hospital in Tehran. Sample group consisted of 44 nurses were selected using convenience sampling method. After pretest, those who scored above medium in aggression and among medium category of job satisfaction and were satisfied were divided into two experimental and control groups accidentally. Then the experimental group participated in 4 weekly 2 hour sessions. After posttest completion, control group took part in the same sessions to comply with research ethics. Data were analyzed using covariance analysis method and SPSS - 20 soft - ware.

2.1. Ahvaz Aggression Inventory (AAI)

That is a self - report inventory with 30 items and a multiple choice scale includes “never”, “rarely”, “sometimes” and “always” are scored from 0 to 3 respectively. This inventory has three factors. The first factor is related to “anger and nervousness”, the second one to “offensive and insulting” and the third one to “obstinacy and malice”. The inventory was constructed by Zahedi far, Najarian and Shokrkon (2000). Subjects will reach a score between 0 and 90 and high scores represent high aggression. Validity was evaluated by Zahedifar, Najarian and Shokrkon (2000) through Buss - Durkee hostility inventory (BDHI) (1957) and Correlation coefficient between BDHI and AAI was reported 0.56 (P ≤ 0.001) [41]. Its reliability was obtained 0.88 for entire and 0.85, 0.80 and 0.72 for anger and nervousness, offensive and insulting, and obstinacy and malice respectively by Cronbach's alpha in Farahani, Bassaknejhad and Davoudi’s (2013) study [42].

2.2. Job Satisfaction Questionnaire (JSQ)

Job satisfaction questionnaire was developed in 2003 by Linz and has 13 items. It is constructed to evaluate the job satisfaction measure in employees and showed favorable validity and reliability in Linz (2003) research [43]. Scoring is based on a five - degree Likert scale from “completely agree” to “completely disagree”. Validity of this questionnaire was confirmed and the reliability of that was obtained 0.86 by Asqari and Hoseini (2014) [44].

2.3. Anger - management Training Program

The present study was run based on anger - management skills package developed by Moutabi (2004) [45].

Session 1: anger definition, physical symptoms, true and false beliefs about anger, aggression consequences, anger causes, various aggressive behaviors, relaxation methods to keep calm in the moment including deep breathing, counting and changing body position and gradual relaxation.

Session 2: cognitive restructuring; discussion about negative self - talk, negative automatic thoughts, replacing positive self - talks, making environmental changes during and after the aggressive situations.

Session 3: assertiveness, adaptive anger expression skills including description of the traumatic behavior occurred, expression of feel, expression of thoughts behind the feel, acceptance of responsibility for thoughts and feels, positive expression of the request and roll playing.

Session 4: problem solving skill training including negative problem orientation recognizing, improving problem orientation, generating alternative solutions, brainstorming and decision making training, practicing [45].

Demographic information of participants including the age, gender, marital status and work experience are shown in Table 1.

Table 1 demonstrates the mean and standard deviation of the age (40.23 ± 7.70) for participants in experimental group and (34.1 ± 4.57) in control group. In terms of gender, the number of participants in two groups was equal, 19 nurses (83.36%) from the experimental group and 20 nurses (90.91%) from the control group were married. The mean and standard deviation of work experience in psychiatric hospital was (13.05 ± 8.40) and (6.95 ± 4.65) for experimental and control group respectively.

The mean and standard deviation of pretest and posttest of two groups are shown in Table 2.

Table 2 shows some differences in experimental group’s posttests. In order to investigate the research hypotheses and covariance analysis, assumptions were investigated at first. Significance level of linearity for pre - test and post - test of variables obtained P ≤ 0.001, multiple linearity between pre - tests of variables was (r = - 0.44, P = 0.05), significance level of homogeneity of variances for aggression and job satisfaction was P = 0.07 and P = 0.80 respectively, and homogeneity of regression was insignificant with P = 0.75 for aggression and P = 0.08 for job satisfaction. So covariance assumptions are established and results of MANCOVA analysis are shown in Tables 3 and 4.

According to Table 3 at least one of the variables was influenced by training significantly. In order to better understand the difference, results of the test of between-subjects effects have been presented in Table 4.

Table 4 illustrates that anger - management training had significant effect on aggression (F = 26.750, P ≤ 0.001, η = 0.401) and job satisfaction (F = 6.071, P < 0.05, η = 0.132).

The present study showed that nurses working in psychiatric hospital express less aggression after anger - management training. Previous findings including [34-39] confirmed similarly that cognitive - behavioral anger-management interventions decline aggression.

We hypothesized that anger - management training can influence job satisfaction although we could not find any research in this regard to evaluate our hypothesis. But, since previous findings including [14-16, 26] have shown that job satisfaction is affected by aggression especially in psychiatric wards we assumed that anger-management training can increase job satisfaction. This hypothesis was confirmed by findings of this study.

The present study illustrates that anger - management training can help nurses in psychiatric hospital to overcome their anger. Improving difficult situations’ management potency will be followed by reducing the maladaptive and aggressive behaviors and alternating more adaptive and efficient strategies [36]. Psycho - education provides necessary knowledge about anger for nurses, helps them to recognize their physical reactions prior to the aggressive behaviors outbreak. So they will be more prepared to control their physical symptoms and their reactions in aggressive situations learning relaxation techniques [39].

In cognitive restructuring, nurses learned how to interpret experiences and events especially those are related to work place. They learned to modify their dysfunctional attitudes and apply more positive - efficient procedures instead. They learned to replace negative self - talk with positives results to less negative thoughts and less anger.

Assertiveness and problem solving skills lead them using more effective coping skills. They will feel less frustration because they are equipped with assertive techniques to express their anger instead of incompatible strategies, problem solving and decision - making skills. Therefore they will be less influenced by work place difficulties.

Anger - management program can decline nurses’ involvements with colleagues and clients, lead to less challenges and result to less anger, more relax, comfort and so job satisfaction in turn, through assertiveness, relaxation and problem solving skills. Restructuring nurses’ attitude toward their job, work place and other related features, will eventuate more positive attitude and so more positive behavior into the work place and its events and lead to less aggression and job dissatisfaction. Results of job satisfaction changes in the present study showed that aggression is an important factor in job dissatisfaction of nurses so that 0.13 of job satisfaction reduced under the influence of anger - management training.

Accordingly, applying anger management training programs in psychiatric hospitals and wards would be helpful and even necessary because 40 percent of aggression and 13 percent of job satisfaction variances are influenced by anger management training as independent variable of this study.