This is an extensive meta-analysis examining the prevalence of depressive symptoms in children and adolescents in China, with 439 studies involving 1,497,524 participants included. In this meta-analysis, we found that the pooled prevalence of depressive symptoms in children and adolescents was 26.17% (95% CI 25.00–27.41%). This pooled prevalence was higher than the 19.85% (95% CI 14.75–24.96%) [23] and 22.2% (95% CI 19.9–24.6%) [26] found in previous relevant meta-analyses. This difference may due to a wider age range of participants in the present study, as the study included primary school students, middle school students, high school students, and undergraduate students. In addition, the pooled prevalence is consistent with the global estimates of child and adolescent depression, as the pooled prevalence estimates of clinically elevated child and adolescent depression was 25.2% [38].

This study found that the detection rate of depressive symptoms was highest among high school students, likely because this group is typically in mid-adolescence, a critical period of physiological and psychological maturation. During this phase, they undergo rapid physical and mental development, face significant academic pressure, experience high parental expectations, and often lack sufficient social experience [39]. Additionally, their hormone levels and the development of the brain's emotion-regulating neural centers remain incomplete, making them more susceptible to psychological, emotional, academic, and interpersonal stress. This stress is exacerbated by high-pressure events such as the National College Entrance Examination (NCEE), or "GaoKao," which is the primary criterion for higher education opportunities [40]. As a result, senior high school students are more likely to experience elevated levels of psychological, emotional, academic, and interpersonal pressure, increasing their risk of depression [40, 41]. These findings are consistent with a previous meta-analysis on the trajectory of depressive symptoms, which revealed that symptoms increase during early adolescence (ages 10–14), peak in mid-adolescence (ages 14–17) during high school, and then decline as individuals transition from late adolescence to early adulthood [42]. Moreover, the study consistently found that the peak in depressive symptoms occurred regardless of group membership, indicating that even adolescents with lower overall levels of depression are susceptible to increased symptoms during this period.

The prevalence of depressive symptoms varied significantly across studies using different scales for assessment. A wide range of depression measurement questionnaires is available. In this study, eight rating scales were included, SDS and CES-D are the most commonly used ones. Consistent with a previous meta-analysis on depressive symptoms in secondary school students, studies utilizing the SDS reported a significantly higher prevalence compared to those using the CDI [27]. The prevalence of depressive symptoms was 18.27% in studies using the CDI, 28.80% in those using the SDS, and 27.98% in those using the PHQ. Additionally, we observed that the three most commonly used scales demonstrated different trends in depressive symptoms over time. This variability may be attributed to the heterogeneity of depression, which presents with a wide range of clinical manifestations [43], such as sadness, insomnia, concentration difficulties, and suicidal ideation. Furthermore, these scales are multidimensional, assessing multiple constructs simultaneously [44]. For example, the SDS, widely used in clinical settings, evaluates four dimensions: psychogenic-emotional symptoms, somatic disorders, psychomotor disturbances, and depressive psychological disorders. The CDI assesses five domains over the past two weeks, including negative mood, interpersonal problems, ineffectiveness, anhedonia, and negative self-esteem. The PHQ-9 consists of nine items assessing the DSM-IV criteria for major depressive disorder, along with an additional item evaluating psychosocial impairment [45]. In summary, the use of different instruments may contribute to the heterogeneity observed in the evaluation of depressive symptoms. Researchers should focus on validating various screening tools. Developing culturally sensitive measures that reflect the socio-cultural context of Chinese children and adolescents is essential.

In this study, boys and girls exhibited similar overall detection rates of depressive symptoms, which contrasts with previous findings. Earlier research indicated that females are twice as likely as males to experience depression, a difference attributed to the sharp rise in depression rates among girls during mid-adolescence [46]. The lack of a gender difference in our study may be due to the wide age range included [26], as this meta-analysis spans from primary school to university-aged individuals. However, gender differences in depressive symptoms vary across age groups. A meta-analysis of 1.9 million individuals from over 90 countries [47] found that gender differences in depression begin to emerge at age 12, peak at age 16, decline by age 19, and stabilize in adulthood. Thus, combining prevalence estimates across age groups may mask these gender differences. Another potential explanation is that the gender gap between Chinese boys and girls may be smaller than in other countries. Research suggests that the depressive trajectories of Chinese boys fall into two subgroups. The majority (85%) experience a gradual increase in depressive symptoms during adolescence (ages 10–19), while the remaining 15% maintain persistently high levels of depression. In contrast, Western boys show a decline in depression during mid-adolescence, while Chinese boys exhibit a steady increase throughout adolescence [27]. The reasons behind this phenomenon remain unclear, and further research is required to explore the role of various risk factors, such as cognitive and interpersonal factors, in shaping this unique gender pattern among Chinese adolescents. Geographic location is another demographic factor that may influence the mental health of children and adolescents, as social resources—including economic support, access to medical care, and educational opportunities—are often unevenly distributed [48]. Additionally, research has shown that higher socioeconomic status and stronger parental educational backgrounds are negatively correlated with depression in offspring [27]. Consistent with previous studies, we observed higher detection rates of depressive symptoms in rural areas compared to urban areas, though the difference was not statistically significant (24.06% vs. 25.78). The findings underscore the urgent need for targeted interventions to strengthen the resilience of children and adolescents in economically disadvantaged regions, such as rural areas, in coping with depressive symptoms [49]. The notably high prevalence rates of depression in plateau regions such as Qinghai and Tibet necessitate further investigation and targeted prevention efforts. This finding aligns with previous studies indicating that the risk of depression increases at higher altitudes [50, 51]. Future studies should examine environmental, social, and cultural factors that may contribute to these disparities, tailoring interventions to specific contexts.

The contribution of this study is multifaceted. First, it provides a comprehensive, nationally representative analysis of depressive symptoms among children and adolescents in China, encompassing a broad temporal and geographical range through the inclusion of 439 studies from 33 provinces, autonomous regions, and municipalities. Second, by identifying the high prevalence of depressive symptoms, particularly among high school students, the study emphasizes the stress-related nature of depression in this population, highlighting key areas for future research and targeted interventions. Moreover, the study underscores the need for improved diagnostic tools, given the heterogeneity observed due to the use of varying scales across the studies. Finally, this research offers crucial insights for policymakers and service providers, aiding the development of effective prevention and treatment strategies for depressive symptoms in children and adolescents. However, some limitations remain. First, the heterogeneity among studies was high, a common challenge in meta-analyses of epidemiological surveys, despite subgroup analyses being conducted. Second, different scales for assessing depressive symptoms were used across the included studies, but no subgroup analyses were performed for different cutoff values of the same scale, potentially contributing to heterogeneity and impacting the results. Third, some studies included in the analysis had a higher risk of bias, with incomplete reporting, such as missing detailed descriptions of non-responders. Fourth, the impact of the COVID-19 pandemic (2020–2023) on mental health outcomes was not explicitly accounted for in the included studies. The pandemic may have altered the context in which depressive symptoms were assessed, potentially affecting the validity and reliability of the findings.

In conclusion, the detection rate of depressive symptoms in this study closely aligns with global rates for children and adolescents. High school students demonstrate a higher prevalence of depressive symptoms compared to other age groups. Notably, detection rates vary significantly depending on the assessment tool used. Among the two most frequently employed scales, the CES-DC yields a lower detection rate that similar to the overall rate. No discernible temporal trend in the detection of depressive symptoms is observed. Substantial regional variations in the prevalence of depressive symptoms among adolescents are evident. For children and adolescents, particularly high school students in rural and plateau areas, there is an urgent need for studies evaluating the effectiveness of various intervention strategies to reduce depressive symptoms.