Background & Aims: Chronic pain is used to describe non-cancerous and refractory pain (1). Chronic pain is a pain that has continued every day for at least three months for the past six months (5). This pain affects the quality of life, so it is necessary to identify and pay attention to the role of chronic pain in mental and physical health. Psychological factors are indirectly related to the process of pain perception. As pain becomes more chronic, the role of psychological factors in the spread and persistence of pain becomes more prominent than the role of biological factors. In this regard, researchers have emphasized the importance of the locus of control (7). Belief in the extent to which a person controls their circumstances, behavior, and thoughts can be considered a factor in determining the severity of pain (8). Numerous psychosocial factors can affect the severity of pain. Studies have shown that emotion regulation and its components directly affect the intensity, frequency and duration of pain perception (11). Emotion regulation is a set of processes that control and evaluate a person's emotional reactions and even change these reactions if necessary, so that the person functions properly (12). The results of studies show that there is a relationship between the locus of control and regulation of emotion. Patients with an internal control source, experience less pain intensity than patients with an external control source. Patients with impaired emotion regulation also experience greater pain intensity (5). On the other hand, most studies have examined the relationship between these components in a correlational manner, but the mediating role of emotion regulation in the relationship between loci of control, pain intensity and the interactive relationship of variables have not been investigated. According to the above points, the present study aimed to investigate the mediating role of emotion regulation in the relationship between locus of control and pain intensity in chronic pain patients
Methods: The method of this research is descriptive and correlational. The statistical population of this study was all patients with chronic pain of Esfarayen in 2019. The sample consisted of 200 patients with chronic pain aged 25 to 45 years who were selected by available sampling method from Imam Khomeini Hospital, specialized clinic of medical sciences and health centers of Shahid Shokouhi, Shahid Montazeri and Imam Reza (AS). Brief pain inventory, health locus of control scale and emotion regulation questionnaire were used as research tools. Correlation test, regression analysis and path analysis were used to analyze the findings. Data were analyzed using SPSS-23 software.
Results: Based on the findings, the mediating role of emotion regulation (re-evaluation- suppression) in the relationship between the source of internal control and pain intensity was confirmed. In this way, individuals with a source of internal control were more likely to use an adaptive reassessment strategy and less of a maladaptive repression strategy, and consequently experienced less pain intensity. Furthermore; In this study, the mediating role of emotion regulation (re-evaluation-suppression) in the relationship between external control source and pain intensity was also confirmed. According to this finding, people with an external source of control were more likely to use a maladaptive suppression strategy that leads to more severe pain.
Conclusion: The results of this study supported the mediating role of emotion regulation in the relationship between locus of control and pain intensity. This finding indicates the importance of emotion regulation in explaining the severity of pain in patients with chronic pain. The findings of this study showed that emotion regulation (re-evaluation - suppression) has a mediating role in the relationship between external control source and pain intensity in patients with chronic pain. Incompatible emotion management strategies, such as repression or catastrophe, lead to reduced physical and social activity, psychological disorders, and feelings of helplessness and lack of control. So that the feeling of lack of control, in turn, intensifies the experience of pain. Thus, people come to believe that they have no sense of control and form a vicious circle (5). One of the most fundamental reasons people turn to dysfunctional emotional regulation strategies such as avoiding, repressing, criticizing, blaming themselves or others, and paving the way for the formation of chronic psychological disorders, including chronic pain, is the belief in lack of internal control (30). Some of the beliefs of most patients with chronic pain are that "my illness is the fault of my spouse, child or boss", "my pain is terrible", "I am going crazy" (31). As a result, patients engage in a maladaptive emotional behaviors and strategies, such as criticizing, blaming themselves or others, or even suppressing their emotions, in order to gain a sense of control over their illness and pain (30). Patients with chronic pain lose more control over the disease and their condition, which leads to more pain. Emotion regulation (re-evaluation - suppression) mediates the relationship between the source of internal control and pain intensity in people with chronic pain. Patients who use adaptive emotion management strategies in the face of problems, ie; problem-oriented strategy, define stressors, and therefore, such people experience fewer negative outcomes and feel more in control of their condition and experience less pain intensity. These patients are more successful in solving problems and dealing effectively with stress caused by life events, and this effective coping and satisfaction in solving the problems makes them feel in control of the stress which caused by important life events. The source of internal control is related to accepting pain and being prepared for change. In general, self-regulation is one of the factors that can be effective in causing or controlling pain in patients. People with chronic pain will be able to prevent information bias in the processing of information that leads to the experience of negative emotions by adjusting their emotions through the relationship between pains and adapt more effectively to their illness (33). Therefore, if the training program of these patients is accompanied by emotion regulation strategies, it can help reduce the severity of pain in these patients.