Introduction

Depressive disorders (also known as depression) are common mental disorders. It involves a depressed mood or loss of pleasure or interest in activities for long periods1. Adolescence is a period of rapid physical, social, and psychological development, during which depression can typically involve a slow, prolonged process, increasing the risk of depression in adulthood by 2–4 times2. A meta-analysis of 51 studies (involving 144,060 adolescents from mainland China) reported that the overall prevalence rate of depressive symptoms among Chinese adolescents was 24.3%3. Many studies have shown that sociodemographic factors4, the school environment and grade5,6, family factors4, health-related behaviors7, risky behaviors8, biological factors9, and exposure to violence and adversity9 are predictors of adolescent mental health problems.

Social capital, a multidimensional concept emphasizing the resources accessible through social networks, has been widely recognized as a key determinant of physical and mental health at both individual and collective levels10,11,12,13. It encompasses social relationships, social support, social cohesion, social participation, social belonging, interpersonal trust, and reciprocity14,15,16,17,18. Social capital influences health by fostering collective action, addressing harmful cultural norms, facilitating information diffusion, and promoting the development of support systems, thereby enhancing self-esteem and mutual respect10,19. These mechanisms play a vital role in mental health promotion and risk mitigation20,21. Research consistently highlights the importance of social capital for the health and well-being of children and adolescents, demonstrating its potential to alleviate depressive symptoms22,23. For instance, a study of adolescents from seven cities in mainland China found that higher levels of social capital were associated with fewer depressive symptoms24. Similarly, a study in South Korea revealed that social capital positively impacted the health of adolescents with immigrant backgrounds25.

Gender differences in adolescent depression have been extensively documented, with females consistently reporting higher levels of depression than males26,27. In the context of Chinese society, traditional cultural norms such as “zhong nan qing nv” (i.e., preference for sons rather than daughters)28 have historically influenced resource allocation within families. This cultural bias, combined with the resource dilution theory—which posits that parental resources (economic, social, emotional, etc.) are distributed more thinly in larger families29—places female adolescents at a disadvantage. In resource-scarce environments, parents may prioritize sons, further exacerbating disparities in resource allocation for daughters30. Studies have shown that female adolescents with lower family and neighborhood social capital are more likely to experience depressive symptoms31.

Poverty alleviation relocation, a cornerstone of China’s poverty reduction strategy, aims to improve the living conditions of impoverished populations by relocating them from harsh natural environments to more sustainable settings32. Empirical evidence underscores the critical role of social capital in facilitating successful migration and sustainable poverty alleviation. For example, Pham and Mukhopadhaya’s33 multilevel analysis of ethnic minority groups in rural Vietnam demonstrated that social capital significantly enhances poverty reduction across multiple dimensions, including income, education, housing, and access to basic services. Similarly, Zhu et al.34 found that community-based social support systems are essential for fostering place attachment and social cohesion among relocated populations in Guizhou Province, China. Tang et al.35 further highlighted that successful migrant integration is better reflected through cultural adaptation, psychological well-being, and social network development than through traditional measures of political and economic integration.

China completed its poverty alleviation relocation efforts in 2020, shifting focus to the subsequent support phase to ensure sustainable development for relocated populations. While relocation offers new opportunities for improved living conditions and policy support34, it also poses significant challenges. Relocation disrupts familiar social networks and environments, forcing adolescents to adapt to new schools and communities, which can negatively impact their mental health36,37,38. The relocation experience varies in terms of distance, scale, and the level of disruption to existing networks. Some adolescents may move only a short distance to nearby towns or villages, while others may be relocated to entirely new regions with unfamiliar social dynamics. Studies have reported increased stress, anxiety, depression, and feelings of loneliness and helplessness among relocated populations39,40. However, some research also highlights the resilience of migrant children41, with the “immigrant paradox” suggesting that adolescent immigrants may experience similar or fewer emotional and behavioral problems compared to their non-migrant peers42. This paradox is often attributed to factors such as strong family bonds, social support, cultural beliefs, and lower rates of substance abuse, which serve as protective buffers against mental health issues43,44,45.

In China, the relocation process for adolescents typically involves moving from inhabitable areas with limited infrastructure to areas with better access to education, healthcare, and employment opportunities. The degree of relocation varies, with some families moving within the same county, while others are relocated to entirely new regions, sometimes hundreds of kilometers away. This variation in relocation distance and environmental change can significantly influence adolescents’ adaptation processes. Despite the growing body of research on social capital and mental health, few studies have specifically examined depressive symptoms among adolescents relocated for poverty alleviation or explored the relationship between social capital and depressive symptoms in this context. To address this gap, this study employs a cross-sectional design in Shanxi Province to investigate the prevalence of depressive symptoms among relocated adolescents, analyze the relationship between social capital and depressive symptoms, and explore potential gender differences. The findings aim to provide evidence-based insights for promoting adolescent mental health in the follow-up support of poverty alleviation relocation, offering valuable implications for China and other developing and underdeveloped countries with similar policy contexts.

Methods

Participants

A face-to-face survey was conducted on adolescents aged 10–19 years46 via a custom-made questionnaire. With a multistage stratified sampling method, this study was conducted from June to August 2023 in Shanxi Province, China. First, four cities in Shanxi Province (Taiyuan, Xinzhou, Linfen, and Lvliang) were selected on the basis of geographical characteristics and economic development levels. Two counties were then randomly selected from each city, and four resettlement sites were randomly selected from each county (if there were fewer than four, all were selected). Finally, 24 resettlement sites were randomly selected.

We used the formula \(n = \frac{{Z_{a}^{2} \times p(1 - p)}}{{d^{2} \times p}}\) to estimate the sample size, where the confidence level was 95% (two-sided) and Za = 1.96. The prevalence of depressive symptoms among Chinese adolescents is 24.3%3, p = 24.3%, and the allowable error d = 10%. Considering a design effect of 1.5 to account for the multistage stratified sampling method, the minimum sample size was adjusted to 435. An additional 20% loss rate was factored in, resulting in a final target sample size of 522. A total of 631 valid questionnaires were collected.

During the survey, we provided respondents with unified instructions, detailing the purpose, significance, and method of completing the questionnaire. The participants filled it out by themselves or had the investigators fill it out on their behalf (the investigators would objectively record the choices) and collect the questionnaires on the spot. If any errors or omissions were found, the investigators would make corrections in time. The inclusion criteria were as follows: (1) aged 10–19 years; (2) belonging to the poverty alleviation relocation population; (3) had the ability to understand and answer questions; and (4) provided informed consent to participate in this study. The exclusion criteria were as follows: (1) individuals whose physical condition was not suitable for participation in the study; and (2) individuals with obvious regularity in answering questionnaires.

This study strictly abided by the Declaration of Helsinki and was reviewed and approved by the Medical Ethics Committee of Shanxi Medical University (No. 2023006) before the survey was conducted. All the respondents signed informed consent forms before they participated in the survey.

Measures

Social capital

This study utilized the Social Capital Questionnaire for Adolescent Students (SCQ-AS) to assess the social capital of adolescents relocated due to poverty alleviation. The SCQ-AS was developed to measure social capital among adolescent students47. The Chinese version of the SCQ-AS has been validated to have good reliability and validity, with an internal consistency index (Cronbach’s alpha) of 0.82948. The SCQ-AS comprises 12 items categorized into four dimensions: “school cohesion” (four items), “school friendship” (three items), “neighborhood social cohesion” (two items), and “trust (school and neighborhood)” (three items). Each item is rated on a scale of 1 to 3, corresponding to “Disagree”, “I do not know, no opinion”, and “Agree”, respectively. Scores range from 12 to 36, with higher scores indicating higher levels of social capital47. In this study, the Cronbach’s alpha coefficient of the scale was 0.730, 95%CI:0.697–0.760.

Depressive symptoms

This study utilized the depression subscale of the DASS-21 (Depression Anxiety Stress Scale). The DASS-21 has been widely used and validated among Chinese university students and adolescents49. The Chinese version of the DASS-21 has good internal consistency and structural reliability50. The DASS-21 consists of 21 items divided into three subscales, namely, depression, anxiety, and stress, each containing 7 items. Each item is scored on a four-point scale ranging from “Never” to “Almost always”, with scores ranging from 0 to 3. The sum of the scores for the 7 items is multiplied by 2 to yield the DASS score51. The Depression subscale (DASS-21-D) consists of items 3, 5, 10, 13, 16, 17, and 21. Scores range from 0 to 42, where scores between 0 and 9 are considered normal, and scores > 9 indicate depression52. In this study, the Cronbach’s alpha coefficient for the scale was 0.759, 95% CI 0.729–0.786.

Covariates

Throughout the entire analysis process, we controlled for demographic and socioeconomic factors, health behaviors and conditions, and the family environment, which have been previously shown to influence adolescents’ perceptions of social capital and depressive symptoms7,23,24,25,31,53. The first set of potential confounding factors included demographic and socioeconomic characteristics such as gender, age, grade level (nongraduating vs. graduating, i.e., grades 6, 9, and 12 grade), and Hukou status (urban, i.e. the adolescents had changed their household registration into urban residents after relocation, vs. rural). The second set comprised health behaviors and conditions, including BMI (divided into three categories according to the data distribution, underweight < 18.5 kg/m2, normal weight 18.5–24.9 kg/m2, and overweight and obese ≥ 25–29.9 kg/m2)54, current smoking (yes/no), current drinking (yes/no), current physical exercise (yes/no. i.e., Whether to engage in outdoor exercise now), and sleep duration (< 7 h, ≥ 7 h)55. The third set included family environment factors such as living with parents (yes/no), parental marital status (married vs. divorced), only child status (yes/no), frequent parental arguments (yes/no. i.e., in the past month, have you seen or heard your parents arguing or having conflicts, answer "sometimes/often" recorded as “yes”, "never/rarely" recorded as “no” ), and parental educational background (primary school or below, middle school, high school or above).

Data analysis

This study aims to explore the relationship between social capital and depressive symptoms among adolescents relocated due to poverty alleviation, considering gender differences. Continuous variables are presented as the means and standard deviation (SD), whereas categorical variables are presented as counts and percentages (%). Binary logistic regression analysis was employed to adjust for confounding variables across different groups. The initial logistic regression model (Model 1) utilized only social capital variables to assess their association with depressive symptoms. In Model 2, the study further adjusted for demographic and socioeconomic characteristics. Model 3 additionally controlled for health behaviors and conditions, whereas Model 4 adjusted for all confounding factors. The results are presented as odds ratio (OR), 95% confidence interval (CI), and corresponding p values. To examine potential gender differences in the relationship between social capital and depressive symptoms, an interaction term (social capital and gender, school cohesion and gender, school friendship and gender, neighborhood social cohesion and gender, or trust (school and neighborhood) and gender) was included in the fully adjusted model (Model 4). To further analyze gender differences in the relationship between social capital and depressive symptoms, analyses stratified by gender were conducted, adjusting for all confounding factors. Given the directional hypotheses proposed in this study (i.e., social capital is expected to have a protective effect against depressive symptoms), the significance level was set at a one-tailed p value < 0.05. All the statistical analyses were performed via SPSS 26.0 (IBM, Armonk, NY, USA).

Results

Descriptive statistics

Demographic and socioeconomic characteristics of the respondents (Table 1). The study included a total of 631 adolescents, with an average social capital score of 31.96 ± 3.67 and an average depressive symptoms score of 4.01 ± 5.48. Among the participants, 15.3% reported depressive symptoms. The sample comprised 49.9% males and 50.1% females, with a mean age of 13.78 ± 2.49 years. The majority of the adolescents (86.5%) had rural household registration (hukou), while the remaining 13.5% had urban hukou.

Table 1 Characteristics of adolescent depressive symptoms
Full size table

Among adolescents with depressive symptoms, higher proportions of females, underweight individuals, and non-only children were observed. Specifically, 59.3% of the adolescents had a BMI classified as underweight, overweight, or obese. Additionally, a significant proportion of the parents of these adolescents had attained a junior high school education level.

Comparative analysis revealed that adolescents with depressive symptoms had significantly lower social capital scores compared to their non-depressed counterparts (p < 0.001). Furthermore, within the social capital dimensions, adolescents with depressive symptoms exhibited significantly lower scores in school cohesion (p < 0.001), school friendship (p < 0.001), neighborhood social cohesion (p < 0.001), and trust (p < 0.01). These findings underscore the association between lower social capital and higher depressive symptoms among adolescents.

Social capital and depressive symptoms of adolescents relocated for poverty alleviation

Binary logistic regression analysis was performed with depressive symptoms as the dependent variable (Table 2). In all the models, social capital was significantly and negatively associated with depressive symptoms after controlling for all the potential confounders. Social capital showed a inverse association with depressive symptoms. In Model 1, adolescents who have been relocated for poverty alleviation with high levels of social capital are less likely to exhibit depressive symptoms (OR: 0.808, 95%CI 0.763–0.856). After controlling for all confounding factors in Model 4, the association between social capital and depressive symptoms remained significant [adjusted odds ratio (AOR ): 0.801, 95%CI 0.754–0.852].

Table 2 Logistic regression analysis of the relationship between social capital and depressive symptoms
Full size table

Moreover, on the social capital scale, the dimensions of school cohesion, school friendship, neighborhood social cohesion, and trust are significantly negatively correlated with depressive symptoms. In Model 1, school cohesion, school friendship, neighborhood social cohesion and trust were negatively associated with depressive symptoms among adolescents who have been relocated for poverty alleviation (ORschool cohesion: 0.670, 95%CI 0.599–0.750; ORschool friendship: 0.621, 95%CI 0.530–0.728; ORneighborhood social cohesion: 0.697, 95%CI 0.592–0.821; ORtrust: 0.842, 95%CI 0.730–0.970). After adjusting for all confounding factors (gender, age, grade, household registration, BMI, smoking, drinking, physical exercise, sleep duration, living style, parents’ marital status, only child, parents’ frequent quarrels, parents’ education level), the negative association between of school cohesion and school friendship and depressive symptoms in Model 4 were further enhanced (AORschool cohesion: 0.664, 95%CI 0.589–0.748; AORschool friendship: 0.621, 95%CI 0.526–0.733).

To explore potential gender differences, an interaction effect analysis was conducted. The results revealed no significant interaction effects between social capital and gender (p = 0.460), school cohesion and gender (p = 0.807), school friendship and gender (p = 0.582), neighborhood social cohesion and gender (p = 0.313), or trust and gender (p = 0.570).

Gender differences in the impact of social capital on depressive symptoms

We further investigated whether the association between social capital and depressive symptoms differed by gender (Table 3). Social capital was a protective factor against depressive symptoms in both male adolescents (AOR: 0.805, 95%CI 0.734–0.883) and female adolescents (AOR: 0.787, 95%CI 0.722–0.858). School cohesion, school friendship, and neighborhood social cohesion were associated with depressive symptoms in both male and female adolescents, but trust was associated with depressive symptoms only in female adolescents (AOR:0.776, 95%CI 0.624–0.965).

Table 3 Logistic regression analysis of the relationship between social capital and depressive symptoms by gender
Full size table

Discussion

In this study, the depressive symptoms scores of these adolescents ranged from 0 to 36, with an average score of 4.01 ± 5.48 and a depressive symptoms prevalence of 15.2%, which was lower than the 35.6% reported in a 2023 cross-sectional study of school-aged children and adolescents (aged 9–18 years) in impoverished areas of China56. These results may be related to the better living environment, more adequate educational resources, better family economic conditions after relocation, and policies of adolescent mental health promotion targeting relocated adolescents as a key group.

The social capital scores of adolescents relocated for poverty alleviation ranged from 18 to 36, with an average score of 31.96 ± 3.67, which was slightly lower than those reported in a 2019 cross-sectional study of 1,577 migrant children attending grades 4–6 in 12 migrant schools in Shanghai, China57. After controlling for all potential confounding factors, the results suggest that there is a significant negative correlation between social capital and depressive symptoms among the relocated adolescents. Those with higher levels of social capital tend to exhibit lower levels of depressive symptoms, indicating a protective effect of social capital against depressive symptoms. This finding aligns with conclusions from previous related research23. Relocation for poverty alleviation involves adolescents leaving familiar environments, losing their original social networks, and adapting to new living conditions, and the stress from these changes may increase the risk of depression among adolescents. However, relocation also signifies substantial improvements in living conditions, living environments, transportation, education, and healthcare resources. High levels of social capital enable adolescents to access more support (e.g., emotional, material, informational) to meet their needs and enhance their social engagement and sense of belonging25, helping them better adjust physically, mentally, and socially in the new environment. Therefore, social capital plays a crucial protective role against depressive symptoms among adolescents relocated due to poverty alleviation.

The study also revealed that the subdimensions of social capital, school cohesion, school friendship, neighborhood social cohesion, and trust (school and neighborhood) were negatively correlated with depressive symptoms among relocated adolescents. School plays a crucial role in adolescent development, and adolescents who perceive a positive school environment, such as feeling safe at school, tend to experience lower levels of depression58,59. High levels of school cohesion are linked to adolescents’ sense of safety60, and school friendships are significantly associated with adolescents’ emotional well-being, psychological health, and subjective happiness61. According to poverty alleviation relocation policies, adolescents are generally placed in schools near relocated communities; thus, they are not a minority in these schools, as many peers share similar experiences. A harmonious school environment and a sense of safety and integration may be associted with lower possibility of depressive symptoms among relocated adolescents. In relocation communities, neighborhood social cohesion is a crucial concept that signifies inclusivity, integration, mutual trust, support, collective efficacy, and a sense of belonging62,63. In rural areas, residents historically relied on kinship ties and shared cultural norms and practices, fostering mutual trust and strong cohesion within villages. After relocation, residents from different villages are resettled in new communities where they must rebuild trust, reciprocity, and norms in this unfamiliar environment. China’s poverty alleviation relocation primarily employs collective resettlement with scattered resettlement as a secondary method, providing favorable conditions for environmental adaptation among relocated adolescent groups. For adolescents relocated for poverty alleviation, this environment may serve as a protective factor against depressive symptoms. Establishing trust and strong cohesion facilitates the establishment of new social connections and networks64, which is beneficial for receiving support when relocated adolescents need it and crucial for adapting to new lives and maintaining good mental health, potentially reducing the risk of depression.

A large body of literature provides significant evidence of gender differences in depressive symptoms, with female adolescents consistently exhibiting higher levels of depressive symptoms26,65. There are also differences in the types and characteristics of social capital between males and females, which may lead to heterogeneity in how social capital influences depressive symptoms across gender groups66,67,68. For instance, studies have shown that females tend to rely more on emotional and relational forms of social capital, such as trust and interpersonal support69, while males may benefit more from structural or instrumental support. Trust, in particular, has been identified as a critical determinant of mental health, as it fosters emotional security and facilitates access to social resources that buffer against stress and depressive symptoms70. The trust dimension in this study was measured by questions about teacher support and adolescents’ trust in classmates and neighbors. The study found that trust in school and community neighbors had a more significant effect on reducing depressive symptoms in female adolescents than in male adolescents.

Within traditional social and cultural contexts, females generally have access to fewer family resources than males. In many cases, boys receive more attention and resource allocation within the family, particularly in rural China, where girls often attract less support from their family, school, and community24. This disparity is further exacerbated in impoverished families, where girls may be required to take on household responsibilities, such as chores and caring for siblings, at a young age. These additional stressors, coupled with limited access to social and emotional support, can increase their susceptibility to mental health issues71. In our study, the significant influence of trust on depressive emotions among female adolescents underscores the importance of external social networks in mitigating depressive symptoms. Females may derive greater emotional benefits from trust-based relationships in school and community settings, which serve as critical buffers against stress and emotional distress. For example, research has shown that girls are more likely than boys to benefit from closer relationships with teachers, which can enhance their sense of belonging and emotional well-being72.

Policy implications

China’s relocation-based poverty alleviation policy provides a model and a fresh research perspective for other developing and underdeveloped countries aiming to lift impoverished youth out of poverty through relocation73,74,75. The relocation-based poverty alleviation policy is not only about resettlement but also a comprehensive social policy involving living conditions, educational resources, healthcare services, and social integration. Governments and communities should prioritize the cultivation and enrichment of social capital among relocated adolescents at the family, school, and community levels to reduce their sense of insecurity and depressive emotions. Moreover, female adolescents need more attention. Schools and communities should pay attention to the mental health of relocated female adolescents by providing targeted psychological counseling and support to help them cope with psychological stress after relocation. Additionally, social capital and mental health are culturally sensitive. Understanding and meeting the psychological health needs of relocated adolescents from different racial, ethnic, and cultural backgrounds is essential. Creating a supportive and inclusive environment that respects diverse cultures will strengthen their cultural identity and sense of belonging.

Limitations

First, this study is a cross-sectional analysis based on data from relocation sites in Shanxi Province, China, which limits the generalizability of the findings, and the causal relationships between social capital and depressive symptoms could not be determined. Second, the data in this study were self-reported, which may introduce recall bias. Third, the study did not explore the mechanisms underlying gender differences in the relationship between social capital and depressive symptoms among relocated adolescents. Future research should expand the scope of the investigation to include larger sample sizes and longitudinal studies.

Conclusions

This study demonstrates that social capital and its subdimensions—including school cohesion, school friendship, neighborhood social cohesion, and trust (school and neighborhood)—are significantly negatively correlated with depressive symptoms among adolescents relocated for poverty alleviation. There are gender differences in the correlation between trust (school and neighborhood) and depressive symptoms, female adolescents benefited more from trust in alleviating depressive symptoms than male adolescents. Policies should focus on enhancing social capital among relocated adolescents, especially in terms of school and community social capital, to alleviate and reduce their depressive symptoms. This is especially true for female adolescents, who experience more severe depressive symptoms and lower levels of social capital than males do.