Introduction

Inflammatory bowel disease (IBD) is a gastrointestinal disorder with unknown etiology, mainly including Crohn’s disease (CD) and ulcerative colitis (UC). It is characterized by chronic, life-long and recurrent symptoms. The incidence of IBD has been on the rise in newly industrialized countries over recent decades, and it has become a global disease1. In addition to the physical burden of the disease, there is increasing recognition of its impact on the psychological well-being of patients with IBD. Patients with IBD are at higher risk for anxiety and depression compared to the general population. It has been mentioned in the literature that nearly one-third of patients with IBD experienced anxiety symptoms and nearly a quarter experienced depression2. These mental health issues are associated with low quality of life among patients with IBD3, and may also influence the severity and progression of the disease4.

Identifying the factors associated with psychiatric disorders in IBD patients has the potential to alleviate anxiety and depressive conditions, thereby enhancing both quality of life and disease management. Various studies have explored the determinants of anxiety and depression in individuals with IBD. For example, a large cohort study identified disease exacerbations and socioeconomic deprivation as risk factors for anxiety and depression in patients with IBD5. Additionally, research by Navabi et al.6 revealed that a history of surgery, female gender, smoking habits, and extraintestinal manifestations were independent predictors of anxiety and depression in this patient cohort. A multicenter survey in China conducted by Zhang et al.7 highlighted that being female, first visit, or experiencing higher disease activity were independent risk factors. Furthermore, a review indicated that individuals diagnosed with CD were more likely to experience anxiety and depression compared to those diagnosed with UC2.

In recent years, there has been a growing scholarly interest in examining the effects of uncertainty related to diseases on the psychological well-being of patients with IBD. Studies have indicated that a correlation between perceived uncertainty among patients with IBD and symptoms of depression. Baudino et al.8 demonstrated that as disease severity increased, it affected the perception of uncertainty among IBD patients, ultimately leading to an increase in depressive symptoms. Similarly, Gamwell et al.9 have shown that adolescents who experienced higher levels of stigma may perceive their IBD as more uncertain and unpredictable, thereby exacerbating depressive symptoms.

In addition, previous studies have demonstrated that uncertainty is a major source of stress and anxiety. The challenges associated with living with IBD expose patients to unpredictability in various aspects of their lives. The etiology of IBD remains unknown, and patients experience uncertain symptoms, such as diarrhea, abdominal pain, unexpected bowel movements, and unpredictable disease recurrence. Patients felt uncertain about the effectiveness, side effects, and long-term consequences of their medications, as well as the progression of the disease, leading to fears of potential complications. This lack of control and predictability over their condition frequently resulted in feelings of distress10,11. These uncertainties compelled patients to lead lives centered around their illness, with IBD influencing nearly every aspect of their existence, including diet, social interactions, family dynamics, and work. Patients perceived these uncertainties as significant stressors, as they must continually confront the looming threat of the unknown12. Research has indicated that coping with unpredictability limited IBD patients’ ability to plan for the future, hindering their capacity to prepare for and respond to upcoming events, ultimately resulting in feelings of anxiety, worry, and fear11. Variations in individuals’ tolerance for uncertainty elicit diverse cognitive, behavioral, and emotional reactions. Difficulty tolerating the unknown is referred to as uncertainty intolerance (IU), a personality trait characterized by aversion to and an intolerable sense of uncertainty13. Individuals with lower tolerance for uncertainty often strive to gain control over their circumstances and eliminate uncertainty14; however, these efforts may inadvertently lead to additional challenges. A meta-analysis has identified significant correlations between IU and clinical symptoms such as social anxiety, obsessive-compulsive disorder, depression, panic, and binge eating15.

Coping generally refers to the cognitive and behavioral responses individuals employ in reaction to negative external events. Effective coping enables individuals to address problems or mitigate associated negative emotions16. Some studies have indicated that IU was mildly to moderately associated with coping styles17. Individuals with high IU scores may resort to maladaptive behaviors and cognitive strategies when faced with uncertainty and potentially adverse situations18. Research has demonstrated that coping styles can mediate the relationship between IU and psychological distress across different populations. For instance, Doruk et al.17 found that female students with low tolerance for uncertainty were more likely to adopt emotion-centered coping strategies, which were linked to more severe depressive symptoms. Parents of autistic children with low tolerance for uncertainty tended to employ maladaptive coping styles, such as avoidant coping, resulting in poorer mental health outcomes19. Taha et al.20 discovered that patients with breast cancer utilized emotion-focused coping to manage their fear of cancer recurrence, which mediated the relationship between intolerance of uncertainty and depressive symptoms. However, there is a lack of relevant studies focusing on patients with IBD, and these relationships warrant further investigation within the IBD population. We hypothesize that the degree of tolerance to uncertainty in IBD patients is associated with anxiety and depression, and we aim to explore whether coping style serves as a mediating factor in this relationship.

Methods

Design and procedure

This cross-sectional study collected survey data between January 1, 2024, and April 15, 2024. Participants diagnosed with IBD, aged ≥ 18 years, and without communication, literacy, or cognitive impairments were included in the study. Participants diagnosed with a mental illness were excluded. We edited the survey content on the Questionnaire Star platform and generated the QR code for the questionnaire. Through convenience sampling, we invited participants attending the gastroenterology department who met the inclusion and exclusion criteria. We explained the purpose and content of the study to the participants, and the ones who agreed to participate in the study signed informed consent. Once Informed consent was obtained, we presented them the QR code, which they can scan using their mobile phone to complete the questionnaire. To prevent duplication or omission, we configured the questionnaire to be completed once on a mobile phone and submitted only after all questions had been answered. Participants had the right to withdraw from the survey at any time. Finally, we eliminated questionnaires with a response time of less than 2 s per item21. Our research protocol was approved by the hospital’s Medical Ethics Committee (Ethics No. xmzsyyky2024-026). All methods were performed in accordance with the relevant guidelines and regulations.

Measurements

Intolerance of uncertainty

The Chinese version of the Intolerance of Uncertainty Scale 12 (IUS-12) was used in this study. The IUS-12 was simplified by Carleton et al.22 based on the IUS-27. The 12 items are scored on a 5-point Likert scale, where higher total scores indicate lower uncertainty tolerance. The Chinese version of the IUS-12 has good psychometric properties, with a Cronbach’s α coefficient of 0.79 and a retest reliability of 0.80.

Coping style

We used the Brief Coping Orientation to Problem Experienced Inventory (Brief-COPE) to assess coping strategies. The Brief COPE contains 28 items that measure the frequency of using 14 different strategies when coping with stressors16. Planning, active coping, acceptance, positive reframing, seeking emotional support, seeking.

informational support, religion, and humor were categorized as adaptive coping strategies. Maladaptive strategies include denial, self-distraction, self-blame, substance use, behavioral disengagement, and venting23.

Anxiety

Anxiety was assessed using the Generalized Anxiety Disorder-7 (GAD-7)24. Participants were asked to assess how often they had been bothered by some typical anxiety symptoms in the last two weeks. The GAD-7 consists 7 items, and each item is scored from 0 to 3 points. Higher scores indicate a more pronounced state of anxiety. We used a total score of 10 as the cutoff value to determine whether participants experienced anxiety or not25.

Depression

We chose the Patient Health Questionnaire-9 (PHQ-9) to assess participants’ depression. The PHQ-9 consists of 9 items with a total score ranging from 0 to 27 points. Participants with a total score of 10 or higher were defined as depressed26. The PHQ-9 is a valid and reliable measurement tool in the Chinese general population27.

Data analysis

The data were analyzed using the SPSS28.0 and macro program PROCESS 3.5. Frequencies and percentages were employed to describe categorical data. For continuous data, those adhering to a normal distribution were characterized by the mean ± standard deviation, while those that did not conform to a normal distribution were represented by the median. The incidence of anxiety and depression was calculated to reflect the participants’ overall mental health status, and additional analyses of anxiety and depression were conducted using the scores as continuous variables. Pearson’s correlation coefficient was used to identify the correlations among IU, coping styles, anxiety, and depression. Model4 in SPSS macro program PROCESS 3.5 was used to test the parallel mediation effect28. Bootstrapping (n = 5000) was performed to estimate the 95% bias-corrected confidence intervals (95% CI). Mediation was deemed significant when the 95% confidence interval (CI) for the indirect effect, from the lower limit (LL) to the upper limit (UL), did not encompass zero.

Results

Descriptive statistics about participants

From January 1, 2024, to April 15, 2024, invitations to fill in the questionnaire were sent to 180 patients, and 173 questionnaires were collected. One questionnaire was excluded because it did not match the age criteria, and nine were excluded due to an average answer time of less than 2 s per question. Finally, 163 valid questionnaires were obtained, with an effective recovery rate of 90.56%. Participants’ ages ranged from 18 to 67 years, with a median of 33.0. The duration of the disease varied from 0 to 30 years, with a median of 5.0. 70.6% of participants were male. Additional demographic information is presented in Table 1.

Table 1 Description of demographic characteristics (N = 163).
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Correlation analysis of IU, coping style, anxiety and depression

The score of IUS was 30.95 ± 10.67, adaptive coping styles was 37.31 ± 9.66, and maladaptive coping styles was 22.78 ± 6.65. There were 27 patients with anxiety symptoms and 33 with depressive symptoms. The prevalence of anxiety was 16.6%, while depression was 20.2%. Pearson correlation analysis revealed a significant and positive correlation between IUS scores and anxiety and depression. Adaptive and maladaptive coping styles were strongly correlated with IU, anxiety, and depression. This indicates a significant relationship among these variables, allowing us to proceed with the mediation effect test. The results can be seen in Table 2.

Table 2 The correlation between IU, coping style and anxiety and depression.
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Test for mediation effects

We utilized the Bootstrap method in the SPSS macro program Process to confirm the mediating role of coping styles among IU, anxiety, and depression. The results showed that the maladaptive coping style partially mediated the relationship between IU and anxiety, as well as between IU and depression. The mediating effect size were 25.5% and 34.2%, respectively. However, the mediating effect of adaptive coping style was not significant, as detailed in Table 3. This suggests that patients with a lower tolerance for uncertainty are more likely to adopt maladaptive coping strategies, which can lead to increased anxiety and depression. The path coefficients of mediating effects can be seen in Figs. 1 and 2.

Table 3 Testing the mediating effects of coping style.
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Fig. 1
figure 1

Mediating effect model of coping styles between IU and anxiety. ***P < 0.001.

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Fig. 2
figure 2

Mediating effect model of coping styles between IU and depression. ***P < 0.001.

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Discussion

The mental health status of patients with IBD has attracted significant attention, and the pathogenesis of emotional disorders is complex. This study explored the coping mechanisms that contribute to anxiety and depression in patients with IBD from the perspective of IU, a factor that has been less emphasized in previous studies. We found that IU was strongly associated with anxiety and depression in patients with IBD, and that maladaptive coping styles partially mediated the relationship. These results may offer new insights for psychological interventions for patients with IBD.

Our study revealed that IUS scores in patients with IBD were positively correlated with anxiety and depression, consistent with findings from previous studies19,29. Yao et al.30 demonstrated that IU was associated with anxiety and depression in the general population of China. A survey carried out by Andrews et al. indicated that intolerance of uncertainty was a significant risk factor for mental health issues in adults when faced with uncertain events during the COVID-19 pandemic. Furthermore, the association between depression and anxiety symptoms intensified over time in individuals with high intolerance to uncertainty31. Research has shown that, in addition to anxiety and depression, IU may also contribute to a broader spectrum emotional disorders, including obsessive-compulsive disorder and eating disorders15. Thus, IU has been recognized as a cognitive vulnerability factor for a range of affective disorders, potentially in various psychiatric disorders and general psychopathology32. Existing studies have shown that psychological treatments can be effective for IU, anxiety, and depression. Cognitive-behavioral therapy (CBT) specifically targeting IU was significantly more effective than general CBT in reducing IU, anxiety, and depression from pre- to post-treatment33. There have been few studies focusing on IU and emotional disorders in patients with IBD. Expressions from patients with IBD regarding the impact of uncertainty on their emotions can be observed in the findings of certain qualitative studies34,35. Rubio et al.36 demonstrated that during MRI scans, the amygdala, cingulate gyrus, insular cortex, and thalamus exhibited significantly higher responsiveness to uncertainty in CD patients compared to healthy controls, with a noticeable trend in the prefrontal cortex and hippocampus. These brain regions are involved in cognitive and emotional responses, threat appraisal, and hyperactivation, suggesting a biased focus on the uncertainty of threats32. Our findings confirmed the association between IU, anxiety, and depression in patients with IBD.

As can be seen from Figs. 1 and 2, IU not only directly affected anxiety and depression but also indirectly influenced anxiety and depression through coping styles. Our results suggest that maladaptive coping styles partially mediate the relationship between IU and anxiety, as well as between IU and depression, which is consistent with the findings in other populations37. It has been shown that increased intolerance to uncertainty is associated with negative coping styles and impulsive decision-making strategies. The Situational Relational Uncertainty Model suggests that people’s attitudes and perceptions of environmental uncertainty directly influence individuals’ emotional and behavioral responses. A high intolerance of uncertainty can lead to dysfunctional behaviors, such as constant information searching, impaired decision making, and poor problem solving38. Individuals with low tolerance for uncertainty tend to psychologically exaggerate the expected likelihood and severity of disasters when faced with stressful events or adversities39. They are more inclined to believe that they will not be able to cope with the situation, which increases the likelihood of developing mood disorders40.

It is worth noting that the confidence interval for the indirect effect of adaptive coping strategies between IU and anxiety and depression in our results contains 0. Therefore, the mediating effect is not significant. Although previous studies have indicated that adaptive coping, as an effective coping mechanism, can mitigate the impact of stressors on mental health. Individuals who actively engage in adaptive coping are more likely to experience a sense of control, optimism, and self-efficacy, which can reduce the development of depressive symptoms and stress41. Almeida et al.42 showed that not all adaptive coping strategies were positively associated with well-being. We analyzed that this result may also be related to the differences in the application of the Brief-COPE in various populations and cultures43.

There are some limitations in this study. The cross-sectional survey was unable to determine a causal relationship among IU, coping styles, anxiety, and depression. This study was a single-center survey with a limited sample size and for convenience sampling, which limits the generalizability of the findings. Multicenter studies with further validation in diverse populations and settings are necessary to explore the relationships between the variables under study.

Conclusion

In this study, we investigated how IU and coping styles influenced the mental health of patients with IBD. Our study revealed a strong connection between IU and the mental health of patients with IBD. Higher levels of IU being are likely to induce anxiety and depression in these patients. IU can contribute directly to, or indirectly lead to, the development of anxiety and depression through maladaptive coping styles. These findings can provide new insights for enhancing the mental health of patients with IBD.