Introduction

Depression is an important measure of college students’ emotional health1. It not only reduces the life satisfaction of college students but also has serious adverse effects on their psychological and behavioral adjustment2. Up to 23.8% of Chinese college students suffer from depression and the prevalence rate has been increasing in the last decade3. Among them, the prevalence of depression among Chinese nursing students is as high as 41%, which is much higher than that of ordinary university students4. The nature of the nursing profession is a comprehensive, practical and humanistic applied science that requires physical and mental exertion5. They must have strong social adaptability, frustration tolerance, and psychological adjustment skills5. Therefore, nursing students are considered a special group among Chinese university students. Their mental health directly affects their study and life, and even the quality of future nursing work and the stability of the nursing team.

With the advancement of internet technology and the proliferation of smart devices, nursing students can access more expertise via smartphones, thereby aiding their clinical decision-making and reducing academic stress6. However, the constant internet access capabilities and ease of access provided by smartphones contribute to the fact that distractions for nursing students have become frequent and prevalent7. Irrational smartphone use has emerged as a significant risk factor for depression in nursing students8,9. With the in-depth exploration of the relationship and mechanisms between smartphone use and depression in academia, the relationship between distraction due to smartphone distraction (SD) and depression has gradually gained extensive attention from researchers.

The SD can be defined as a person’s inability to focus on the environment, people and events around them due to the versatility and attractiveness of a smartphone10. It may be triggered by external factors such as message notifications, phone calls, others being online and fear of missing out11. Using smartphones can frequently interrupt people's primary tasks, which in turn interferes with cognitive processes and abilities, as well as cognitive function7,12, and are strongly associated with distraction and impaired performance. It has been found that frequent loss of attention affects areas of executive functioning, which has important implications for attention, decision-making, behavioral performance, higher-order thinking and regulation of emotions13,14. Frequent SD not only disrupt people’s normal lives but are even closely related to mood disorders such as depression15. More importantly, distraction may reinforce an individual’s habitual or compulsive use of smartphones16. Excessive use of smartphones has been shown to be a significant predictor of depression17. According to a survey, 24.7% of nursing students reported having been distracted by their smartphones18. There was a significant positive correlation between smartphone addiction and depression among nursing students8. Social comparison theory may be one of the important theories to explain the above mechanism. Social comparison theory suggests that an individual’s viewing of “idealised” information about others induces an upward social comparison, which is a key factor in inducing an individual to experience more stress and depression19,20. However, the mechanisms behind SD and depression in nursing students are not yet fully understood.

Rumination may be one of the key mechanisms explaining the relationship between SD and depression in smartphones. Rumination is considered a maladaptive cognitive coping strategy. Reactive style theory suggests that rumination refers to the persistent and repetitive thinking about the emotional state of an individual after experiencing a negative event and the reasons for it, the possible consequences, and the details of the event, rather than actively solving the problem21. It has been shown that excessive use of smartphones affects an individual's ability to regulate affective emotions and induces ruminative thinking, which prolongs and exacerbates the experience of negative emotions, such as anxiety and depression22. The stress-response model of rumination suggests that rumination is more likely to be activated after experiencing a stressful event23. Smartphones can easily lead students into rumination, causing them to feel more frustrated and helpless when studying and working24. The SD negatively affect students’ offline interpersonal activities, academic performance, and feel more increase individual stress load25. Increased stress can further exacerbate negative emotions and rumination26. It is well known that rumination is closely associated with negative affect, is a susceptibility factor for depression21. And, it also mediates the effect of some depressive risk factors on individual depression (e.g. mobile phone addiction, passive social networking site use, interpersonal sensitivity, social exclusion, social support)27,31. Thus, rumination may be a mediator of SD leading to depression.

The distraction and crowding out of traditional face-to-face social time caused by smartphones may have propelled the process of social withdrawal, resulting in an increased risk of depression. The characteristics of social withdrawal mainly include adults whose lifestyles are concentrated at home for up to 3–6 months or even longer; they develop mental isolation due to long-term social isolation, leading to depression, anxiety, and other mental illnesses; they may suffer from impaired daily functioning32. Kato et al. provided a detailed description of the features of social withdrawal in their diagnostic system, including a lack of social participation, face-to-face social interaction, indirect communication, and isolation33. The online communication platforms provided by smartphones can weaken interpersonal interactions offline, reducing social engagement34. According to the displacement hypothesis, the replacement of face-to-face interpersonal relationships with online connections is hypothesized to reduce communication with others, resulting in a significant decrease in the scale of social engagement35. This phenomenon can even lead to people's isolation, marginalization, and social withdrawal from offline social interactions, triggering negative emotions such as loneliness and depression36. Studies have shown that individuals with social withdraw have a six-fold increased risk of developing depression, and young adults between the ages of 20 and 29 are at high risk37. Given this, nursing students may be a high-risk group for social withdrawal. In summary, social withdrawal may be a mediating variable of SD and depression.

According to the theory of response styles of rumination, rumination hinders problem solving and interpersonal communication, thereby prolonging and exacerbating individuals' negative emotions38. People often selectively showcase their “idealized” side in various ways on social media platforms via smartphones39. Social comparison theory suggests that individuals who engage in long-term upward social comparisons will underestimate their abilities and induce negative self-evaluations, thereby reducing confidence in face-to-face interactions and increasing social anxiety20. Social anxiety has been shown to prompt individuals to develop social withdrawal behaviors, avoiding the reality of social interaction and leading to an increased risk of depression40. This pathological comparison can cause the individual to experience more stress and contribute to depression. Therefore, the present study hypothesized that rumination and social withdrawal may play a chain mediating role in the effect of SD on depression.

A review of previous studies found that research on smartphones and mental health has focused more on smartphone addiction and problematic smartphone phone use. Most of the research on SD are still in its infancy, mainly including scale development and validation, incidence surveys, and neuroscience7,18,41,42. In the nursing student population, previous studies have only investigated smartphone-induced distraction and analyzed the negative effects associated with it (e.g., threat to patient safety, reduced learning ability, impaired nurse-patient communication, etc.)7,18,42. Therefore, there is a relative paucity of inquiry into the mechanisms between smartphone distraction and nursing students’ mental health.

As such, the purpose of this study is to explore the mediating role of rumination and social withdrawal in the effect of SD on depression. The results of this study have important implications for nursing educators in guiding nursing students to use smartphones correctly and reduce the risk of depression. This study constructed a chain mediation model based on the literature review and formulated the following hypotheses (Fig. 1):

Figure 1
figure 1

Hypothetical mediation model.

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H1: There is a significant and positive correlation between SD, rumination, social withdrawal, and depression.

H2: Significant direct effect of SD on depression in nursing students.

H3: Rumination and social withdrawal act as mediators in the relationship between SD and depression, respectively.

H4: Rumination and social withdrawal play a chain mediating role in the association between SD and depression.

Methods

Design

This was a cross-sectional study conducted at various universities in Wuhan, China, with convenience sampling.

Participants

These students were invited to participate in the online questionnaire survey through WeChat/QQ social software. Inclusion criteria: (1) Undergraduate nursing students studying full-time at a university; and (2) Consent to participate in this study.

The researcher estimated the minimum sample size required for this study based on the sample size formula. The specific formula is \(n = \frac{{\left( {Z_{{\frac{\alpha }{2}}} } \right)^{2} p \left( {1 - p} \right)}}{{d^{2} }}\)43, where α = 0.05, Z = confidence level (α/2), p = prevalence, and d = marginal error. The incidence of SD was estimated at 24.70% according to a cross-sectional study by Cho and Lee18. With a 95% confidence level, a margin of error of 0.05, and considering a 20% sample attrition rate, it was estimated that at least 344 questionnaires should be distributed to participants. Initially, a total of 632 undergraduate nursing students from four grades participated in this study. After excluding questionnaires with excessively fast response speed, strong regularity in answers, and a high number of missing values, the researchers obtained a total of 574 valid questionnaires, resulting in an effective response rate of 90.82%.

Measurements

1) The Chinese version of the Smartphone Distraction Scale (C-SDS).

The scale was developed and validated by Throuvala et al.41, and translated and revised into Chinese by Zhao et al.44. The C-SDS used in this study comprises 16 items, with three dimensions of attentional impulsivity (8), multitasking (4), and emotion regulation (4). Participants were required to rate each item on a 5-point Likert scale ranging from 1 (almost never) to 5 (almost always). The total score ranges from 16 to 80, with higher scores indicating higher levels of SD. In this study, the Cronbach’s α was 0.905.

2) Patient Health Questionnaire-9 (PHQ-9).

The PHQ-9 was developed in 2001 based on the diagnostic criteria of DSM-IV and was translated into Chinese and revised by Bian et al. in 200945. The scale is a self-report questionnaire that measures the presence and severity of depressive symptoms. The scale has 9 items and is scored on a 4-point Likert scale ranging from 0 (not at all) to 3 (almost every day), with higher scores indicating higher levels of depression in individuals. In this study, Cronbach’s α was 0.899.

3) Ruminative Response Scale-10 Items (RRS-10).

The RRS-10 is a self-assessment scale designed to assess people’s level of rumination. It has two subscales, contemplation and rumination, each with 5 entries. The scale uses a 4-point Likert scale ranging from 1 (never) to 4 (always). The RRS-10 has good reliability and validity in a population of Chinese university students46. In this study, Cronbach’s α was 0.924.

4) Hikikomori Questionnaire-25 items (HQ-25).

The scale was translated into Chinese and revised by Hu et al.47. It contains a total of 25 items including three dimensions of socialization (11), isolation (8), and emotional support (6). The scale was scored on a 5-point Likert scale ranging from 0 (strongly disagree) to 4(strongly agree), with 7 items being reverse scored. Higher scores represent more severe individual social withdrawal. The scale has a total score range of 0 to 100, with 42 being the critical score. In this study, the Cronbach’s α was 0.917.

Data analysis

The SPSS version 25.0 statistical analysis software was employed in this study for the basic organization and analysis of the survey data. There were only a few missing values in the general demographic information, which were replaced with the mean value. Descriptive statistics were performed for the general demographic data, with frequency and percentage (n, %) used for count data and mean ± standard deviation used for measurement data. The Harman one-way test was used to detect common method bias, and Pearson correlations were utilized to examine the correlations between variables. Model 6 of PROCESS version 4.2 was employed to investigate the mediation model, while controlling for covariates. Prior to analyzing the mediation model, the raw data were standardized to minimize the effect of scoring differences for each variable. The 95% confidence interval (CI) for the mediating effect was estimated using a bias-corrected nonparametric percentile Bootstrap method with 5000 sample draws. P < 0.05 was used in this study to indicate a statistically significant difference.

Ethical considerations

All procedures in this study during the survey process conformed to the ethical standards for human experimentation set forth by the ethics committee and the revised 1975 Declaration of Helsinki. This study was approved by the Ethics Committee of Hubei University of Chinese Medicine (2021-ICE-015). Participants signed an online informed consent form with knowledge of the purpose and significance of the study. And, verbal consent was again sought from all participants prior to the questionnaire. This study was conducted using an anonymous survey without any specific identifying information of the participants (e.g., IP address, student name, student ID card or ID number) as a way to protect the personal information of each participant.

Results

Common method biases

The Harman one-factor test was used in this study to test for common method biases, which identified 14 factors with eigenvalues greater than 1. The first factor explained 23.28% of the total variance, which is less than the critical standard of 40.00%, indicating that there was no significant common method bias in this study48.

Sample demographics

This study involved a total of 574 undergraduate nursing students, including 68 (11.80%) male students and 506 (88.20%) female students. Their average age was 20.08 ± 1.05, and the number of students from rural and urban areas were 284 (49.50%) and 290 (50.50%), respectively. The percentages of nursing students using smartphones < 3 h, < 6 h, < 9 h, and ≥ 9 h per day were 3.00%, 34.70%, 42.30%, and 20.00%, respectively. The number of nursing students who use their smartphones for more than 6 h per day is as high as 62.30% (Table 1).

Table 1 Characteristics of the nursing students (n = 574).
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Correlation analysis

There were significant positive correlations among SD, rumination, social withdrawal, and depression, providing support for hypothesis 1. Gender and age were included as control variables in the subsequent analysis49 (Table 2).

Table 2 Bivariate correlations of the measured variables.
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Mediation effect analysis

The results showed that SD was able to directly and positively influence depression (β = 0.353, P < 0.001), supporting hypothesis 2. Additionally, SD had significant direct effects on rumination and social withdrawal (β = 0.355, P < 0.001; β = 0.212, P < 0.001), and rumination and social withdrawal also significantly positively depression (β = 0.336, P < 0.001; β = 0.285, P < 0.001) (Table 3).

Table 3 Direct effects of SD and depression, rumination, and social withdrawal.
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The results of the mediation analysis showed that the Bootstrap 95% CI for the mediating effects of rumination and social withdrawal did not include 0. It indicated that rumination and social withdrawal both played a mediating role in the relationship between SD and depression, confirming hypothesis 3. The Bootstrap 95% CI for the mediated chain of SD → rumination → social withdrawal → depression also did not include 0. It indicated that the chained mediating effects of social withdrawal and rumination were also significant, confirming hypothesis 4. The results showed that the total indirect effect accounted for 58.64% of the total effect. The mediating effects of rumination and social withdrawal were 33.71% and 17.28%, respectively. The serial mediating effect of rumination and social withdrawal accounted for 7.65% (Table 4).

Table 4 Total, direct, and indirect effects of each path in this model.
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The final chained mediation model is presented in Fig. 2.

Figure 2
figure 2

Chain mediation model.

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Discussion

This study constructed a mediation model to comprehensively understand the underlying mechanism of SD on depression. Importantly, all four hypotheses of this study were confirmed. The results of this study demonstrated a significant direct positive effect of SD on depression in nursing students, and possibly also indirectly through rumination and social withdrawal.

The SD not only correlated significantly with nursing student depression but also directly and positively affected nursing student depression, consistent with previous findings50. And, the percentage of direct effect of SD on depression was 41.36%. The results of this study added to previous research findings that SD negatively affects mental health51. Although nursing students can relieve heavy academic or emotional stress through smartphone use52, it can easily trigger habitual and addictive use16. The direct positive effect of smartphone addiction on depression has been confirmed in several studies8,9,17. This study also found that up to 62.3% of nursing students used smartphones for more than 6 h per day and it was significantly associated with SD and depression53. Although nursing students have a positive attitude towards smartphones, it is difficult to maintain a state of balance between study, work, and life54. Therefore, educators should guide nursing students in the proper use of smartphones to reduce the risk of depression among nursing students.

The first half of this mediation model indicated that rumination plays a mediating role in the relationship between SD and depression among nursing students. The SD, as a maladaptive way of information acquisition, activates negative personality traits (such as rumination) and triggers depression55. Prolonged SD among nursing students interferes with cognitive processes and attention resource allocation, leading to interruptions in primary tasks, negatively impacting academic performance, and thereby increasing personal stress burden25. Chinese nursing students experience significant personal stress, which is a major contributing factor to mental health issues. The increase in external pressure can trigger rumination in individuals26. People who are in a chronic state of rumination tend to get stuck in negative emotional experiences and induce depression56. In this study, rumination had a significant indirect mediating effect of 33.71% in the relationship between SD and depression, highlighting the crucial mediating role of rumination. Therefore, schools and hospitals should keep abreast of the current state of nursing students’ thinking and help them develop positive thinking habits to prevent and reduce rumination through regular mental health assessments, psychological counseling services, mental health education, the organization of mental health activities, and the use of digital monitoring tools.

The results of the mediation model showed that social withdrawal mediated the effect of SD on depression. It has been demonstrated in several studies57,58. People diverting too many attentional resources to smartphones can interfere with the establishment and development of real-life interpersonal relationships, reduce social skills, and lead to social avoidance behaviors59. This poor distribution of attention can further stimulate negative emotions such as depression, anxiety, and helplessness60. Additionally, impaired interpersonal communication skills are detrimental to establishing a trusting relationship between caregivers and patients, increasing work stress61. The gradual increase in the incidence of social withdrawal and SD among college students will seriously affect the mental health development of nursing students62. However, studies have confirmed that using smartphones by nursing students in clinical settings to release emotional stress and escape from reality is beneficial to social and emotional well-being54. Educators should look at the pros and cons of smartphones objectively, pay high attention to the motivation of nursing students to use smartphones, and guide them well. At the same time, schools should actively engage in various forms of activities to provide nursing students with social opportunities and increase their social contact, thereby reducing the risk of social withdrawal and depression.

Rumination and social withdrawal play a chain mediating role in the effect of SD on depression. The range of negative effects of SD on cognitive function, emotion regulation, and interpersonal development was again validated. Rumination is in most cases just a negative way of coping to avoid reality, and high rumination can exacerbate the negative effects of other factors on an individual’s emotional adjustment63. People who get caught up in thinking about past negative social events before social activities can contribute to the development of social withdrawal behaviors, leading to an increased risk of depression40. Previous studies have demonstrated a six-fold increase in the risk of depression in individuals with social withdrawal37. This study demonstrates the crucial role of rumination in SD, social withdrawal, and depression. As educators, we should guide students to view information on the Internet objectively and correctly, promote positive self-evaluation, maintain good social relationships, and reduce the risk of depression, which is of great significance.

Limitations

This study has limitations. First, the cross-sectional design cannot establish causality between these variables. Second, the study used self-report measures and did not monitor the nursing students’ smartphone behaviors. Finally, the study used convenience sampling, recruiting participants from undergraduate nursing majors in Wuhan, China. Therefore, caution should be exercised in extrapolating these findings to other populations, and more controlled and larger sample studies are needed. Despite these limitations, this study has theoretical and practical significance.

Conclusion

This study found that SD had a significant direct effect on nursing student depression. Also, this study highlighted the important mediating role of rumination and social withdrawal in the effect of SD on nursing students’ depression. With the advent of the Internet era and the popularity of smartphones, SD has become widely prevalent among nursing students. As nursing students are an important reserve force in Chinese healthcare service, the negative effects of SD on nursing students' mental health should attract the focused attention and timely intervention of educators.