Introduction
Depression is a common affective disorder that has become one of the most important factors threatening human health. Darío Moreno-Agostino et al1 found that the prevalence of depression is on the rise worldwide. Under the stress of study and pressures of life, college students are especially prone to mental health problems, particularly depression, and this issue has increasingly raised wide social concern. Researches on the mental health of college students have found that the prevalence of depression among Chinese college students in recent years has been as high as 20–60%.2,3 A large-scale study on Chinese college freshmen found that about 65.55% of them have experienced depression.4 In contrast to general college students, military college students, as the incoming, high-quality military talents for the future army, are an important power for medical support and the maintenance of the army’s fighting force. As military college students, they are in a critical period for their developing personalities and growing talents, when they initially face the pressure of military life pressures, such as the environment of the military camps, the mode of management, interpersonal relationships, studies, and military training and tasks, are more likely to make them prone to emotional problems like depression. In recent years, the prevention and timely treatment of psychological problems among military personnel have become a significant issue in the military medicine field in many countries.
Depressed mood is affected by a variety of factors. With the rise of positive psychology, more and more attention has been paid to the impact of positive psychological resources on depression, of which character strengths and positive emotions are important examples. Positive psychology posits that individuals have the inherent capacity for growth, self-fulfillment, and happiness. If a person lacks these abilities, he or she may develop depression. Prior studies have shown that character strengths are strongly associated with depression, mental health, and life satisfaction.5
Character strengths can be defined as positive traits reflected in thoughts, feelings, and behaviors. They exist in degrees and can be measured as individual differences.6 Moreover, these strengths change dynamically over time, and thus they can be enhanced through cultivation and training. The Resource-Conservation-Theory posits that when an individual interacts with their environment, resources like character strengths can enable the individual to better cope with external pressures and challenges and minimize negative emotional experiences, thus enabling him or her to obtain more resources.7 As character strengths are an important component of an individual’s positive psychological resources, their relationship with depressed mood has received increasing attention. On the emotional level, character strengths can lead to more positive experiences;8 on the level of physical and mental health, character strengths are defensive factors that play a protective role in the face of mental health problems (eg, depression), stress, and adversity.9 Character strengths are positively associated with positive emotional experiences, hope, and happiness, but negatively correlated with anxiety and depression.10 A study on nurses found that character strengths are directly and negatively correlated with depressive symptoms and positively correlated with mental health.5 Character strengths interventions can increase the levels of individual satisfaction, positive emotions, etc., and reduce problems such as depression and anxiety.11–13 Studies of character strengths-based curricular interventions have demonstrated significant increases in students’ positive experiences of well-being, life satisfaction, and positive emotions after the interventions.14
Positive emotion, defined as a pleasurable subjective experience, typically emerges when an individual’s needs are fulfilled. Positive emotions can facilitate individuals’ proactive behavioral tendencies. Fredrickson’s Broaden-and-Build Theory of positive emotions posits that positive emotions can broaden an individual’s thoughts and actions, build lasting physiological and psychosocial resources, and bring about more positive feedback, thereby alleviating negative emotions and depressive symptoms.15 A core feature of depression is mood dysregulation, ie, an increase in negative emotions and a decrease in positive emotions. The absence of positive emotions is an important manifestation of depression. Empirical research has shown that depression is associated with difficulties in up-regulating positive emotions and that depressed individuals are less likely to use rational positive emotion regulation strategies. Positive emotions can lead to positive outcomes such as higher levels of physical and mental health, healthier behaviors, and better interpersonal relationships.16 Positive emotions can increase psychological resources, improve the cognition of setbacks and failures, enhance psychological resilience, and boost the ability to resist stress and adversity as well as the capacity to recover from negative states.17 Therefore, we may as well try to leverage positive emotions to improve an individual’s depressive state and enhance their mental health.
Life satisfaction is an individual’s subjective experience of his or her evaluation of his or her own life quality according to his or her own standards, and such life satisfaction is the basic condition of his or her mental health.18 Scholars believe that life satisfaction can negatively predict the level of depression, suggesting that enhancing an individual’s life satisfaction may improve depressive conditions.19–24 Scholarly research has indicated that depression is significantly negatively correlated with life satisfaction.25,26 Additionally, studies have shown that life satisfaction is negatively correlated with anxiety and depression while being positively correlated with psychological resilience.21 In Turkey, with a measure of depression, a positive correlation was found in pregnant women concerning the number of children they had and a negative correlation with life satisfaction.22 In a cross-sectional study, life satisfaction was found to be negatively associated with depressive symptoms, and depressive symptoms were comorbid with loneliness, anxiety, and dependency.27 These findings suggest that life satisfaction could serve as a potential psychological target for intervening in depression, but its mechanism of action needs to be further explored by incorporating group characteristics.
Research has shown that positive emotions have significant direct effects on life satisfaction and academic engagement.28 Network analysis reveals that positive emotions are highly correlated with higher levels of life satisfaction. The Directed Acyclic Graphs revealed that positive emotions significantly influenced life satisfaction.29 The findings underscore the importance of positive emotions in enhancing life satisfaction. Other studies have found that positive emotions were significantly associated with life satisfaction in the expected way.30 Consistent with the broaden-and-build theory, positive emotions appear to predict life satisfaction.31 Cross-lagged analysis indicated that positive emotions predicted life satisfaction after controlling for auto regressor effects. Positive emotions were positively associated with life satisfaction across the different time points as well.32
Although previous studies have investigated the relationships among character strengths, positive emotions, life satisfaction, and depression, the following limitations still exist: First, most prior studies have focused on single effect only, and whether character strengths influence depression through positive emotions and life satisfaction via a chain mediating effect has not been fully explored; Second, there is currently no research on how character strengths affect depressive symptoms among military college students.
Therefore, this study aims to fill this research gap by constructing a chain mediation model to analyze the intrinsic association between character strengths and depression in military college students. In this study, the following four hypotheses were proposed:
H1: The character strengths of military college students are significantly negatively predictive of depression.
H2: Positive emotions play a mediating role between character strengths and depression.
H3: Life satisfaction plays a mediating role between character strengths and depression.
H4: Character strengths affect the depression of military college students through the chain mediation of positive emotions and life satisfaction.
By examining the above hypotheses, this study aims to accurately identify the influencing factors and underlying mechanisms of depression in military college students from the unique perspective of positive psychology, so as to provide a solid theoretical basis and practical guidance for the development of scientific and effective depression intervention strategies, thereby improving the mental health of military college students and ensuring the smooth progress of their learning, training, and future military career development.
Materials and Methods
Study Design
This study was a descriptive cross-sectional survey of military college students and adhered to the STROBE statement.
Setting
On December 10th, 2024, we used a convenience sampling method to recruit 813 undergraduate students at a military college.
Study Size
According to the statistical method,33 the sample size is typically 5 to 10 times the number of study variables. In this study, there were 135 variables (including demographic data and all scale variables). Considering potential invalid questionnaires, a 10% increase in the sample size was necessary. Therefore, a minimum sample size of 743 was calculated to meet the requirements of this study.
Participants
A total of 860 questionnaires were distributed, of which 813 valid questionnaires were collected, yielding a validity rate of 94.5%. Participants were eligible for inclusion if they (1) were healthy based on self-report; (2) with no self-reported history of neurological or psychiatric illnesses; (3) consented to participate in the study; and (4) non-psychology majors. Of the participants, 66.9% were male, 55.7% were from towns and cities, 94.6% were of Han nationality, and the average age was 21.19±4.26 years old (Figure 1). The exclusion criteria were: (1) students presenting with major physical disorders potentially interfering with assessment; (2) students without valid written informed consent.
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Figure 1 Participants recruit flow diagram.
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Data Collection Procedure
This study utilized an online survey hosted on the Wenjuanwang platform. Specifically, the survey was administered by researchers who were trained to administer the questionnaires after class during students’ free time, whereby all students in each class unit completed it by scanning a QR code in the classroom via WeChat. Prior to this process, students were explicitly informed that the survey was anonymous, intended solely for academic research, and required independent and truthful responses. Furthermore, the questionnaire’s landing page displayed an Informed Consent Form outlining the research purpose; consequently, students were required to acknowledge it via a checkbox before proceeding. During the completion phase, researchers emphasized that items assessing positive emotions and depression specifically reflected participants’ emotional states during the preceding week. This study complies with the ethical principles of medical research as set out in the Declaration of Helsinki, and approved by the Ethics Review Committee of The First Affiliated Hospital of the Fourth Military Medical University (KY20234188-1).
Measures
Demographic Characteristics
A self-made questionnaire was used to measure the demographic characteristics of participants. The contents of the questionnaire included: gender, age, place of origin and nationality.
Character Strengths Questionnaire
The Chinese Virtues Questionnaire as revised by Wenjie Duan et al was used to measure character strengths.34 The scale measures 24 character strengths across three dimensions (Relationship, Vitality, Conscientiousness) through 96 items. All items are scored on a five-point Likert scale from 1 = very unlike me to 5 = very much like me. The average score for each subdimension is calculated. The higher the score, the higher the level of character strengths. The Cronbach’s α coefficient of the total scale in this study was 0.987.
The Satisfaction with Life Scale (SWLS)
The SWLS was formulated by Diener35 to evaluate overall life satisfaction. It is a unidimensional scale with 5 items; all scored on a seven-point Likert scale from 1 = very much not satisfied to 7 = very much satisfied. Higher total scores indicate greater life satisfaction. The Cronbach’s α coefficient of the scale in this study was 0.894.
Positive Emotions
Positive emotions were measured using the section on positive emotions from the Positive and Negative Affect Scale (PANAS). This scale was formulated by Watson, Clark, and Tellegen and revised by Huang Li, Yang Tingzhong, and Ji Zhongmin.36 It has been shown to have good reliability and validity. The scale comprises 10 items, designed to assess the emotional level experienced by respondents in the past week, all scored on a five-point Likert scale from 1 = very slight or not at all to 5 = very strong. The total score is calculated with higher scores indicating stronger positive emotions. The Cronbach’s α coefficient of the positive emotion subscale in this study was 0.910.
Center for Epidemiologic Studies Depression Scales (CES-D)
The Chinese version of the CES-D developed by Radloff, as revised by Wang Xiangdong et al37 was used here. It consists of 20 items designed to identify depression in the general population in the past week. Higher total scores indicate greater frequency of depression. The total score ranges from 0 to 60 points, with a cut-off of 16 points for depressive symptoms. The Cronbach’s α coefficient of the CES-D in this study was 0.969.
Statistical Methods
SPSS 26.0 software was used to calculate descriptive statistics, common method bias, Pearson’s correlation analysis, and a t-test. AMOS 24.0 and Structural Equation Modeling (SEM) were used to test the mediating effects of positive emotion and life satisfaction and evaluate the model, with character strengths as the predictive variable and depression as the dependent variable.
Common method bias was tested using Harman’s single factor test and Confirmatory Factor Analysis. For normally distributed quantitative data, the description was based on means and standard deviations. An independent samples t-test was used for comparison between two groups. The correlations between variables were analyzed using Pearson correlation analysis. The mediation effects of the variables were analyzed using hierarchical regression analysis and structural equation modeling techniques. The standard errors (SE) and 95% confidence intervals (CI) of the parameter estimates were obtained by taking 5,000 Bootstrap samples. If the 95% CI did not include zero, the effect was considered significant.38
Results
Test for Common Method Bias
In order to control for common method bias, all responses in this study were anonymous, so as to minimize participants’ privacy concerns and ensure the reliability and validity of the scale. However, due to the limitations of the measurement population, it was not possible to eliminate common method bias in the procedural control. Therefore, Harman’s single factor test was used to perform an exploratory factor analysis on all scale items.39 The results showed that there were 19 factors with eigenvalues greater than 1. The factor with the highest explanatory power accounted for 21.89% of the total variance, a proportion that is below the critical threshold of 40%.40 Therefore, there are no serious common method biases in this study.
Table 1 shows the results of comparing the CFA fit between the multi-factor model and the single-factor model. The chi-square value of the multi-factor model (x2= 30,756.784) was considerably lower than that of the single-factor model (x2= 97,633.979), indicating the multi-factor model fitted significantly better than the single-factor model (Δx2= 66,877.195, Δdf= 137, p < 0.001) and no serious common method bias existed in the study.41
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Table 1 Comparison of Multi-Factor and Single-Factor Models
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Comparison of Total Scale Scores and Demographic Differences of the Variables
The top five core character strengths of the female participants were integrity, fairness, love, teamwork, and tolerance, while the top five core character strengths among males were integrity, fairness, love, teamwork, and gratitude.
The results of comparison of the groups demonstrated that, gender differences were observed in the scores for vitality and conscientiousness (t=4.91, p<0.001). There were also gender differences in the total scores for character strengths (t=3.602, p<0.001), life satisfaction (t=2.65, p=0.008), and positive emotions (t=3.31, p=0.001), with relatively higher scores for males. Depression levels differed by place of origin (t=−2.09, p = 0.04), with urban college students scoring lower than their rural counterparts. Detailed comparisons of the total scores of the scales are shown in Tables 2 and 3.
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Table 2 Comparative Analysis of Differences in Gender (M±SD)
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Table 3 Comparative Analysis of Differences in Place of Origin (M±SD)
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Correlation Analysis of Character Strengths, Positive Emotions, Life Satisfaction, and Depression
A Pearson’s correlation analysis was conducted for all continuous variables. Relationship, vitality, conscientiousness, positive emotions, life satisfaction, and character strengths were all highly positively correlated, with correlation coefficients all exceeding 0.5. The total score of character strengths, as well as the sub-scales, was significantly and negatively correlated with depression, as were positive emotions and life satisfaction. The correlation coefficients of each variable are shown in Table 4.
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Table 4 Correlation Analysis of Variables
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Regression Analysis of Character Strengths, Positive Emotions, Life Satisfaction, and Depression
Using the suggestions of Wen Zhonglin for the mediating effects test,42 the chain mediation effect was detected. Positive emotions and life satisfaction were set as mediator variables, character strengths as the independent variable, depression as the dependent variable, and the stepwise regression method was used to test the mediation effect. The results are shown in Table 5.
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Table 5 Regression Analysis Between Variables
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After adjusting for gender and place of origin, character strengths significantly and negatively predicted the depression level of military college students (β = −0.326, p < 0.01). This indicates that the direct effect of character strengths on depression was significant. Therefore, Hypothesis 1 is supported. After including positive emotions in the regression equation, character strengths significantly and positively predicted positive emotions (β = 0.696, p < 0.01), but the prediction of depression by positive emotions was not significant (β = −0.077, p = 0.11). Therefore, positive emotions did not play a partial mediating role in the relationship between character strengths and depression; Hypothesis 2 was not supported. After including life satisfaction in the regression equation, character strengths significantly and positively predicted life satisfaction (β = 0.356, p < 0.01), and life satisfaction significantly and negatively predicted depression (β = −0.192, p < 0.01). Therefore, life satisfaction partially mediated the relationship between character strengths and depression; Hypothesis 3 is supported. After including positive emotions and life satisfaction in the regression equation, positive emotions significantly and positively predicted life satisfaction (β=0.363, p<0.01), indicating the existence of chain mediation between positive emotions and life satisfaction; Hypothesis 4 is supported. In summary, it can be concluded that positive emotions and life satisfaction play a chain mediating role between character strengths and depression in military college students.
These results indicate that correlation analysis established significant relationships among the four variables. The regression analysis confirmed the significance of the paths from the independent variable to the mediator and from the mediator to the dependent variable, indicating that the key prerequisites for mediation have been validated. This allowed for further testing of the potential chain mediation effect and the examination of indirect effects within each model.
Analysis of the Chain Mediation Effect of Positive Emotions and Life Satisfaction
The results for the parallel mediation effect and the chain mediation effect of character strengths and depression are shown in Figures 2 and 3 respectively. The fit indices of two models based on 5000 bootstrapped samples are shown in Table 6.
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Table 6 Fit Indices of Parallel Mediation and Chain Mediation Models
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Figure 2 Results of the parallel mediation analysis. Notes: The values shown are the standardized coefficients. The bold values represent R². ***p<0.001; **p<0.01.
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Figure 3 Results of the chain mediation analysis. Notes: The values shown are the standardized coefficients. The bold values represent R². ***p<0.001; **p<0.01.
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This study adopted the chain mediation model due to its superior model fit indices: χ²/df=3.484 (<5), RMSEA=0.055 (<0.08), with all indicators (GFI=0.992, AGFI=0.971, CFI=0.996) outperforming the parallel mediation model. Furthermore, this model better aligns with the theoretical pathway of “character strengths → positive emotions → life satisfaction → depression.
The deviation corrected percentile bootstrap method (5000 repetitions) was used to verify the indirect effect (see Table 7). The results show that the total standardized mediation effect of positive emotions and life satisfaction in the link between character strengths and depression was −0.163, with 95% confidence intervals of [−0.256, −0.030]. This indicates a very clear direct correlation between character strengths and depression.
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Table 7 Chain Mediation Effect Test of the Mediating Role of Positive Emotions and Life Satisfaction in the Relationship Between Character Strengths and Depression
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Specifically, the mediation effect included the following three pathways: (1) Character Strengths → Positive Emotions → Depression (indirect effect −0.045); (2) Character Strengths → Life Satisfaction → Depression (indirect effect −0.074), and (3) Character Strengths → Positive Emotions → Life Satisfaction → Depression (indirect effect −0.044). Collectively, the 95% confidence interval for Pathway 1 included zero (β = −0.326, SE = 0.052, p=0.468), indicating nonsignificant mediation. Pathways 2 and 3 showed significant indirect effects (β = −0.074 and β = −0.044, respectively; 95% CIs excluded zero). Pathways 2 and 3 accounted for 35.54% of the total effect, with individual contributions of 22.29% and 13.25%. Therefore, although positive emotions did not have a significant mediation effect between character strengths and depression, the chain mediation of positive emotions and life satisfaction between the two variables was significant. This suggests that character strengths may negatively affect depression through life satisfaction and may also indirectly predict depression through the chain mediation of positive emotions and life satisfaction.
Discussion
This study reveals the mechanisms through which character strengths influence depression in military college students. The findings demonstrate that character strengths not only directly and negatively predict depression levels but also indirectly reduce depression through two pathways: (1) a single mediation of life satisfaction and (2) a chain mediation involving both positive emotions and life satisfaction.
This study assessed the levels of the 24 strengths in the character of military college students, of which the top five strengths were sincerity, fairness, love and being loved, teamwork, and tolerance. Sincerity, fairness, and love and being loved are the core strengths, in agreement with findings based on the US general population.43 In this study, male military college students were found to score higher than female students on the total character strengths scale and the variables of vitality, conscientiousness, life satisfaction, and positive emotions. There was no significant gender difference in the scores of the relationship variable. This is inconsistent with the findings of studies on students from general college students,44 for whom females scored higher than males on the relationship variable. The reasons may lie in aspects such as military training and values. In military training, male military college students often undertake more rigorous physical fitness and endurance training tasks, and the high-intensity training model continuously hones their willpower. At the value level, societal and military cultures place more prominent expectations on males for the role of perseverance and determination, and male military college students are more inclined to demonstrate character strengths in training and daily life. In terms of place of origin, college students from urban areas scored higher than those from rural areas in their appreciation of beauty and lower in depression, suggesting that military academies should pay more attention to rural college students and cultivate their awareness and value of the appreciation of beauty.
The results regarding the mechanism of the effect of character strengths on depression in military college students showed that character strengths and their sub-scales were significantly negatively correlated with depression, which means that individuals with higher levels of character strengths exhibited fewer depressive symptoms. This is consistent with the findings of previous studies.5,13,43,45,46 Character strengths can significantly negatively predict depression, and thus Hypothesis 1 is supported. Prior studies have shown that interventions based on character strengths can alleviate depression.47,48 Research in positive psychology has shown that character strengths can serve as a buffer against stress and depression, fulfilling a protective function to assist college students in developing cognitive flexibility and adaptability as well as accelerating their psychological recovery from stressful situations.
This study found that positive emotions were highly positively correlated with character strengths and variables and were significantly negatively correlated with depression. Character strengths significantly predicted positive emotions and negatively predicted depression, in agreement with the results of prior studies.46 Specifically, military college students with higher levels of character strengths had more positive emotions and lower levels of depression. However, the non-significant path via positive emotions was retained in Table 5 for full disclosure but excluded from mediation interpretations. The positive emotions did not show a significant predictive effect on depression in this study, inconsistent with the findings of prior studies on general college students.49 That is, positive emotions did not partially mediate the relationship between character strengths and depression, and thus Hypothesis 2 was not supported. It may be that, based on the Broaden-and-Build Theory, although positive emotions can broaden cognitive and behavioral patterns and build psychological resources, specific stressors in military environments—such as high-intensity training, strict disciplinary constraints, and task uncertainty—continuously deplete individuals’ psychological energy, potentially offsetting the broadening effect of positive emotions on cognition and their constructive role in psychological resilience. In this context, positive emotions fail to fully exert their buffering and regulatory functions, leading to their nonsignificant predictive role in depression among military college students.
Our study also shows that life satisfaction was highly positively correlated with character strengths and significantly negatively correlated with depression, a view that has reached general consensus among scholars in China and abroad.50–52 The results of the regression analysis show that character strengths had a significantly positive predictive effect on life satisfaction, while life satisfaction had a significantly negative predictive effect on depression. That is to say, individuals with higher levels of character strengths tended to have higher life satisfaction, and the higher the life satisfaction was, the less depressed the individual was. This is consistent with the results of prior studies.53–55 Further analysis showed that life satisfaction partially mediated the relationship between character strengths and depression in military college students; Hypothesis 3 was thus supported. Character strengths influence the level of depression by increasing individuals’ life satisfaction. For example, individuals with character strengths such as hope, curiosity, and love have higher life satisfaction and lower levels of depression. It may be worth attempting to influence life satisfaction through interventions targeting character strengths, thereby directly or indirectly alleviating depression. According to the two-factor model of mental health, life satisfaction and depression are positive and negative indicators of individual mental health, respectively. In the general population, the character strengths most significantly associated with life satisfaction are hope, enthusiasm, love, gratitude, and curiosity. In a study of recovery from illness, physical illness was found to be less likely to lead to a decrease in life satisfaction in people who were brave, kind, and humorous. Millis found that the character strengths of hope, enthusiasm, humor, gratitude, and perseverance were the strongest predictors of life satisfaction in patients.56,57 The development of character strengths may serve as a pathway to improve the subjective experience of quality of life. Higher levels of life satisfaction can help individuals better cope with difficulties and stress in life, reducing the occurrence of depressive symptoms.
This study found that military college students’ positive emotions and life satisfaction played a chain mediating role in the relationship linking character strengths to depression, consistent with our Hypothesis 4. This implies that, in addition to developing character strengths, it is crucial to emphasize the cultivation of positive emotions and the enhancement of satisfaction as effective means to mitigate depression. This chain mediating process indicates that positive emotions and life satisfaction form a continuously influencing pathway between character strengths and depression. Individual-environment interaction theory suggests that an individual’s development is influenced by both their external social environment and the individual’s intrinsic traits. As an internal characteristic of individuals, when confronting external adversity, resources like character strengths and positive emotions may assist individuals in adapting to adverse environments. This adaptation has the potential to enhance life satisfaction, which could, in turn, contribute to a reduction in depression. Military colleges may as well emphasize the cultivation of character strengths in education and management, and strive to reduce the occurrence of depression by promoting life satisfaction and positive emotions, thereby enhancing the students’ mental health.
In research on the influencing factors of depression, genetic, environmental, psychological, social, and biological factors are all associated with it. Current studies suggest that depression is a heterogeneous disease driven by multiple factors. The genetic and neurobiological research indicates that depression shares biological foundations with other affective disorders, collectively forming part of a continuum or affective disorder spectrum rather than independent disease categories.58 Meng et al’s studies have shown a significant positive correlation between perceived stress and anxiety and depression.59 Based on scholarly perspectives, depression is associated with stress.60–62 Previous research has noted that individuals with high neuroticism are more prone to maladaptive responses to stressful events and are at a higher risk of mental health problems, such as depressive symptoms.63 Although this study did not include military-specific moderators, its key findings demonstrate that the core mediating pathway via positive emotions and life satisfaction remains robust even without controlling for military environmental stressors. This provides a new perspective for understanding the mechanisms influencing depression and developing intervention strategies.
Practical Implications
This study preliminarily validates the chain mediating the role of positive emotions and life satisfaction in the relationship between character strengths and depression among military college students, highlighting the importance of proactive mental health interventions. Several possible avenues for future intervention design could be considered:
First, to develop a mental health framework from a strengths-based approach.64 The focus of mental health for military college students is the exploration and cultivation of character strengths, and the application of these strengths, with an emphasis on prevention rather than addressing issues after they arise. On the one hand, to conduct courses for strengths identification and enhancement, using psychological assessment tools to help students understand their own strengths and designing targeted training modules to reinforce them. On the other hand, to set up practical projects for strengths application, encouraging students to proactively use their character strengths to solve problems in military training and daily tasks, such as students with leadership strengths to organize squad training and those with creativity strengths to participate in tactical innovation.
Second, while exploring and cultivating character strengths, we focus on positive psychological collaborative interventions based on the PERMA theory to enhance positive emotions and life satisfaction. PERMA theory is a theory of happiness in positive psychology that encompasses five elements: positive emotions, relationships, engagement, meaning, and accomplishment.65 Here are some possible suggestions: a) In daily military life, positive emotions can be discovered through the “Three Good Things” exercise, created through gratitude visits or writing gratitude letters, and enjoyed through storing mementos and other practices, thereby enhancing feelings of happiness and life satisfaction.66 b) In military training and missions, emotional regulation abilities can be improved through mindfulness training, imagery training, etc., to enhance emotional stability.67 c) In team collaboration tasks, train positive communication, cultivate proactive constructive communication and empathy, establish strong interpersonal relationships, and provide emotional support.67,68
This approach enables military college students to better adapt to their life in military academy and cope with challenges there, ultimately promoting growth and positive adaptation to future military tasks.
Limitations and Future Directions
The results of this study have enriched the theoretical results on the influence mechanism of depression and can play a guiding role in the development of mental health intervention schemes for military college students. However, it still has some shortcomings worth noting.
First, this study employed cross-sectional data, which precludes the determination of temporal sequences or causal relationships. Future research should utilize longitudinal data to elucidate the causal relationships between character strengths, positive emotions, and life satisfaction. Second, the study was conducted only with military college students from a specific military academy, and the gender ratio was not balanced. Future research with military college students should be conducted on a larger scale and with a more balanced gender ratio. Third, this study primarily focused on the chain mediating the role of positive emotions and life satisfaction in the link between character strengths and depression. However, there may be other additional variables, particularly military-specific stressors, that play mediating or moderating roles. Therefore, follow-up studies should take these other variables into consideration. Fourth, the data are derived primarily from self-reports by trainees, which may be susceptible to the social desirability bias and other confounding factors. In the future researches, researchers should consider integrating multiple measurement methods and research designs with high ecological validity, such as third-party assessments and experience-sampling methods.
Conclusion
The findings of this study reveal significant relationships among character strengths, positive emotions, life satisfaction, and depression within a population of military college students. Notably, character strengths demonstrate a significant direct effect on depression. Furthermore, they exert an indirect effect on depression via the chain-mediating roles of positive emotions and life satisfaction. However, the cross-sectional design warrants a cautious interpretation of these findings. These findings suggest that mental health educators at military colleges can design comprehensive intervention programs to enhance students’ character strengths. This enhancement can thereby increase their positive emotions, which in turn can improve life satisfaction, ultimately reducing depression levels. Adopting such a comprehensive intervention approach is likely to be proven more effective.
Data Sharing Statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.
Ethics Approval and Informed Consent
This study was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Review Committee of The First Affiliated Hospital of the Fourth Military Medical University (KY20234188-1). All subjects gave informed consent.
Author Contributions
All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.
Funding
This research was funded by the National Natural Science Foundation of China (72374208) and the Interdisciplinary Integration Special Project (2024JC046).
Disclosure
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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