Colorectal cancer (CRC) ranks third in word wide cancer incidence and second in cancer-related mortality [1, 2]. Permanent colostomy removes the tumor and creates a stoma on the abdominal wall to provide a new artificial pathway for waste elimination [3, 4]. Despite the obvious clinical benefits of a stoma, it still impairs the patient’s physical, psychological, and social functioning, leading to stoma-related problems . Physical changes, such as damage of self-image, incontinence, leakage, and uncomfortable clothing make it difficult for patients to adjust . In the psychological aspect, patients are faced with multiple impacts of appearance, touch, vision, and smell associated with the stoma, causing psychological distress . And in the social aspect, the relationships with family members and friends may be damaged, self-awareness seems to be challenged .
As a positive psychological structure, psychological well-being is always used to measure the overall state of life . It is the personal understanding and affective values of life events, including emotional reactions to events, good judgment, and awareness of satisfaction . With the deepening of research on well-being, its positive effects on health outcomes have been explored. Previous studies have shown that well-being was related to more healthy coping tendencies, better disease prognosis, improved quality of life, and healthy longevity [10, 11, 12]. Obviously, interventions that promote well-being to improve health outcomes and reduce the negative effects of the disease are undoubtedly an important issue.
The Positive Psychology Intervention (PPI) is an effective therapy developed in psychology, which can promote well-being and reduce ill-being [13, 14]. Compared with other therapies (e.g., cognitive behavioral therapy, interpersonal therapy, and problem-solving therapy) for dealing with mental health issues, PPI focuses less on psychological defects and more on identifying and establishing on positives (e.g., positive experiences, factors, and scenarios). Besides, such intervention is less complex and applicable in a shorter time range, which has attracted much attention in recent years [15, 16]. Currently, PPI has been successfully applied to the general populations and clinical patients, and has shown its effect on improving mental health status and well-being [17, 18, 19, 20]. Although evidence-based PPI that can improve positive aspects has been developed and widely disseminated, it has not been used among patients with a permanent stoma in China and many other countries.
In the existing literature, in addition to the lack of examination of the effect of PPI in the context of patients with a permanent stoma, there is also insufficient research on the mechanism of PPI promoting well-being. Although numerous studies showed that PPI could promote health outcomes and well-being by improving positive states, few studies have used parallel mediation models to test the mechanism by which PPI increases well-being . Several mechanisms may account for PPI effects, including changes in attentional deployment and cognitive reappraisal during the processes of emotion regulation . Additionally, PPI may increase positive emotions, thoughts, and behaviors as well as psychological personal resources . Psychological capital is generally defined as an individual’s positive psychological development state, which is characterized by:(1) Strive to complete challenging tasks and always keep confident (self-efficacy); (2) Adhere to the goal and redirect the path to success for the goal if necessary (hope); (3) Maintain a positive attitude towards the present and future success (optimism); and (4) Persevere and surpass to achieve success when troubled by difficulties and adversity (resilience) .
The Build and Broaden Theory  proposed that positive effects broaden the scopes of cognition, attention, and action, and established individual psychosocial resources. Psychological capital is interpreted as a positive perception of events that stimulates success based on unremitting effort and persistence [23, 25]. The positive activities contained in PPI could increase psychological capital. In turn, these positive effects of psychological capital can mediate the effect of PPI on individual’s well-being [22, 25]. Given the PPI is a conscious and positive activity focusing on goals, which facilitates participation in thinking about a person’s positive future and formulating ways to achieve goals, we believe it makes sense that increased psychological capital, including self-efficacy, hope, optimism, and resilience, mediates the effects of PPI on well-being. And these mediating variables may occur simultaneously with changes in well-being.
Therefore, the main purpose of our study is to examine the efficacy of PPI on improving well-being (i.e., increasing life satisfaction and decreasing psychological stress) among patients with a stoma. In addition, we considered that psychological capital is the mediating active ingredient of PPI to improve life satisfaction and reduce psychological stress, thus, our secondary purpose is to examine the efficacy of the PPI in increasing psychological capital (self-efficacy, hope, optimism, and resilience). Finally, in order to better understand the psychological processes that make a PPI efficacious, this study would use Structural Equation Modeling (SEM) to explore the action mechanism of a specific intervention in increasing well-being.