Objective: To study the relevant correlation of anger-out (expression of anger toward other persons or objects in the environment) or anger-in (holding in or suppression of angry feelings) with life events, so as to gain a better understanding of present-day social influences and assess which life events trigger anger. This study proposes the new hypothesis that “life events constitute originating factors of anger-triggered emotional action”.
Methods: A cross-sectional study using epidemiological methods enrolled 1 107 workers. According to the common features of anger and existing data, workers in the cities Jinan and Qingdao of Shandong Province were enrolled as target population. Investigators were specially trained and used designed survey instruments to investigate. Subjects were asked to complete the General Scale of study population, State-trait Anger Expression Inventory-2 (STAXI-2) and Life Events Scale. Logistic regression was used to analyze the correlation between anger-out or anger-in and life events.
Results: Those workers displaying anger-out showed positive correlations between the anger-out emotion and life events “not satisfied with sexual life or single” (OR: 2.877), and “dissatisfaction with career status” (OR: 3.308). Further statistical analysis showed that anger-out emotion in the worker population was triggered by life events, which constituted risk factors for them. This suggested that the workers would generate anger-out emotion if they improperly dealt with these trigger life events. In the workers with anger-in, positive correlations were found between the anger-in emotion and life events “own (lover) abortion” (OR: 2.209), “dissatisfaction with career status” (OR: 2.054), and “strained relations with superiors” (OR: 2.714). Further statistical analysis showed that the anger-in emotion in the worker population was triggered by life events, which constituted risk factors for them. This suggested that the workers would generate anger-in emotion if they improperly handled these life events. However, negative correlations were found between anger-in and the life events “marriage”, which suggested that the workers would not generate anger-in emotion but potentially generate other emotions if they faced this stimulus event.
Conclusion: Research results support the hypothesis, life events serve as a stimulus, which can cause anger, both anger-out and anger-in. The research results will expand understanding of the etiology of emotional injuries in traditional Chinese medicine; from the perspective of etiology it will provide a related theoretical basis and support data.

Key words: emotion, anger, anger-out, anger-in, life events, cross-sectional studies, epidemiologic methods