Adverse childhood experiences (ACEs) refer to the prolonged exposure of individuals during their formative years to detrimental environmental conditions characterized by instability and insecurity. Such adverse environments pose continuous threats, resulting in emotional deprivation and unmet needs. ACEs encompass five categories of childhood maltreatment: emotional abuse, physical abuse, sexual abuse, emotional neglect, and physical neglect, as well as five forms of familial dysfunction during childhood: parental separation/divorce, domestic violence, substance abuse, mental illness, and incarceration (22, 23). The emergence of ACEs is closely linked to the family environment, particularly parenting styles (24). When parents frequently employ negative parenting practices, such as denial and neglect, adolescents may develop a tendency to attribute negative events to themselves in a persistent manner, leading to self-defeating beliefs (e.g., “I always fail,” “I am not good enough”). Prolonged exposure to negative experiences can foster a sense of helplessness in adolescents, reinforcing maladaptive thought patterns and rendering them oblivious to positive or neutral information, thereby contributing to the onset of ACEs (25, 26). Notably, research indicates that the use of violence and harsh, indifferent educational practices during parenting can inflict significant emotional neglect, emotional abuse, and physical abuse on children (27). Conversely, children who experience adversity are more likely to report feelings of parental rejection, indifference, and overprotection (13, 28).

Studies have demonstrated that ACEs is associated with a range of chronic diseases, including depression, severe obesity, heart disease, cancer, liver disease, and chronic lung disease (29, 30). LeMoult et al. found that individuals with a history of ACEs are 2.5 times more likely to develop depression compared to those without such a history, with a greater number of ACEs correlating with more severe depressive symptoms (11). Furthermore, ACEs, particularly bullying and sexual abuse, may increase the risk of depressive symptoms in adolescents through heightened bodily inflammatory responses (31). In summary, ACEs may serve as a significant mediating factor in elucidating the impact of parenting styles on adolescent depressive symptoms.

Learning burnout refers to a state of excessive depletion of physical and mental resources and energy exhaustion that arises from prolonged exposure to stress. It is positively correlated with psychological issues such as anxiety, depression, emotional instability, and obsessive-compulsive symptoms (32). In China, academic life constitutes a significant aspect of adolescents’ lives, compounded by substantial social competition pressures. Many parents impose high academic expectations on their children, often employing parenting strategies that restrict leisure activities and undermine perceived progress to motivate learning (33). As a result, some adolescents, enduring this high-pressure environment and experiencing low achievement satisfaction, gradually develop a sense of alienation from their studies and enter a state of learning burnout characterized by energy depletion. When adolescents encounter negative learning experiences, such as frustration, fatigue, dissatisfaction, and low self-esteem, these adverse psychological states can lead to detrimental changes in their emotions or cognition, thereby impacting their mental health (33). Consequently, learning burnout may serve as a mediating factor between parenting styles and depressive symptoms in adolescents.

Based on an integrated theoretical framework of psychology and neuroendocrinology—chronic stress, dysregulation of the HPA axis, impaired brain plasticity, and a decline in academic functioning model—children who experience prolonged exposure to abuse and neglect exhibit persistent hyperactivity or hypoactivity of the hypothalamic-pituitary-adrenal (HPA) axis. This dysregulation leads to disruptions in cortisol rhythms, which in turn damage neural circuits in the hippocampus and prefrontal cortex responsible for memory, attention, and executive control, thereby hindering the acquisition of academic skills. Once academic difficulties manifest, negative feedback from failures in learning and adverse interactions with teachers can result in emotional exhaustion and avoidance of academic tasks, contributing to the emergence of learning burnout (22). A longitudinal study found that elevated cortisol levels in children aged 7 to 24 months could predict lower academic performance at age 5, while an increase of one point in the ACEs score during the first grade was associated with a 1.3 to 1.9-fold increase in the risk of subsequent academic failure (34). In summary, negative parenting styles and ACEs as early and chronic stressors in adolescence, potentially leading to learning burnout by affecting the HPA axis and brain structure.

This study aims to explore the chain mediating effects of ACEs and learning burnout between parenting styles and adolescent depressive symptoms, utilizing a large sample of adolescent data and employing structural equation modeling (SEM). The following hypotheses are proposed (see Figure 1 ): Hypothesis 1: ACEs and learning burnout mediate the relationship between parenting styles and depressive symptoms (Path 1, Path 2); Hypothesis 2: There exists a chain mediating effect of ACEs and learning burnout between parenting styles and depressive symptoms (Path 3); Hypothesis 3: There are differences in the parenting styles of fathers and mothers in relation to the pathways leading to adolescent depressive symptoms; Hypothesis 4: Gender differences exist in the pathways through which parenting styles influence adolescent depressive symptoms.

In response to the Ministry of Education’s initiative to enhance psychological assessments for students, the Education Bureau of a district in Chengdu, in collaboration with our institution, distributed psychological assessment questionnaires to all primary and secondary schools in the region in November 2021. The target population for the questionnaire included students from the fourth to the twelfth grade. Prior to the completion of the questionnaires, informed consent was obtained from both the students and their guardians. Additionally, our institution provided standardized training for 20 psychological educators from the collaborating schools, which included topics on privacy protection and emergency response. Those who passed the assessment subsequently served as primary examiners. The assessments were conducted by class, with students logging into a secure system using their identification numbers in a computer lab. The psychological educators read standardized instructions and emphasized the principles of anonymity and voluntary participation, while the homeroom teachers supervised the entire process. The system was equipped with mandatory validation features, allowing each IP address to submit responses only once. During the data screening phase, a dual quality control process was implemented: the system automatically filtered out invalid data, and manual reviews were conducted to exclude questionnaires with logical inconsistencies between reverse-scored and forward-scored items, as well as those exhibiting patterned responses. Through these measures, a total of 60,011 valid questionnaires were collected. This study received ethical review and approval from the Ethics Committee of Sichuan Provincial People’s Hospital and Sichuan Provincial Mental Health Center.

From the 60,011 questionnaires, we identified 34,539 adolescents in the first year of junior high to the third year of senior high school. Subsequently, we utilized the Childhood Trauma Questionnaire-Short Form (CTQ-SF) to select 3,323 adolescents who experienced moderate to severe childhood trauma. Among these individuals, we further screened for those with a PHQ-9 score of ≥5, resulting in a final inclusion of 3,180 high-risk adolescents in this study ( Figure 2 ).

The Short Egna Minnen av Barndom Uppfostran (s-EMBU) questionnaire was employed to assess parenting styles (35). The s-EMBU consists of two versions: the father’s version and the mother’s version, each containing 21 items, resulting in a total of 42 items. It encompasses six dimensions: paternal rejection, maternal rejection, paternal emotional warmth, maternal emotional warmth, paternal overprotection, and maternal overprotection. Each item is rated on a 4-point scale ranging from 1 to 4, with items 29 and 30 scored in reverse. A higher score in a given dimension indicates a greater tendency of parents to exhibit that particular parenting style. This questionnaire has been widely utilized in research involving Chinese adolescents and has demonstrated good reliability across three dimensions (36).

ACEs were assessed using the Childhood Trauma Questionnaire-Short Form (CTQ-SF) (37). The CTQ-SF comprises 28 items that evaluate five dimensions: emotional abuse, physical abuse, sexual abuse, emotional neglect, and physical neglect. Each item is rated on a 5-point scale from 1 to 5, with total scores ranging from 28 to 140. A higher total score indicates a more severe level of childhood trauma. In this study, moderate to severe childhood trauma was defined as meeting at least one of the following criteria: emotional abuse ≥ 13, physical abuse ≥ 10, sexual abuse ≥ 8, emotional neglect ≥ 15, and physical neglect ≥ 10 (37). The scale has been shown to possess good reliability and validity in China (9).

Adolescent learning burnout was assessed using the Adolescent Learning Burnout Scale, which consists of 16 items encompassing three dimensions: physical and mental exhaustion, academic alienation, and low achievement (38). Each item is rated on a 5-point scale from 1 to 5, with total scores ranging from 16 to 80. A higher total score indicates a greater severity of learning burnout. This scale has been widely employed in related research and has demonstrated good reliability and validity (39).

Depression was evaluated using the Patient Health Questionnaire Depression Scale-9 item (PHQ-9), which assesses the severity of depressive symptoms experienced over the past two weeks (40). The PHQ-9 consists of 9 items, each rated on a 4-point scale from 0 to 3, with total scores ranging from 0 to 27. A higher total score indicates a more severe level of depression.

Data analysis was conducted using SPSS 26.0. Descriptive statistics, including frequency, mean, and standard deviation, were utilized to characterize the sample. The Kolmogorov-Smirnov test was employed to determine whether the measurement data followed a normal distribution. Harman’s single-factor test was conducted to assess common method bias, and Pearson correlation analysis was used to examine the relationships among the scores of various scales. Structural equation modeling was constructed using Amos 24.0 to investigate the relationships among parenting styles, ACEs, learning burnout, and depression. Standardized regression coefficients were calculated to derive path coefficients, and fit indices were employed to evaluate the goodness of fit between the data and the hypothesized model, including the standard chi-square (χ²/df), root mean square error of approximation (RMSEA ≤ 0.06), adjusted goodness of fit index (AGFI ≥ 0.90), goodness of fit index (GFI ≥ 0.90), comparative fit index (CFI ≥ 0.90), normed fit index (NFI ≥ 0.90), and incremental fit index (IFI ≥ 0.90) (41–43). The bootstrapping method was utilized to test the statistical significance of the direct, indirect, and total effects of the hypothesized model.

A total of 3,180 participants were included in this study, with an average age of 14.28 ± 1.63 years. The demographic characteristics of the participants and the results of key variables are presented in Table 1 .

Table 2 indicates a significant relationship between adolescent depression and parental upbringing styles. Specifically, parenting styles characterized by rejection and denial (r = 0.131, p < 0.01) as well as overprotection and interference (r = 0.518, p < 0.01) are positively correlated with depression. Additionally, ACEs (r = 0.193, p < 0.01) and learning burnout (r = 0.246, p < 0.01) also exhibit a positive correlation with depressive symptoms. Conversely, parenting styles that emphasize emotional warmth and understanding are negatively correlated with depression (r = -0.252, p < 0.01). Furthermore, parental emotional warmth and understanding are negatively associated with ACEs (r = -0.389, p < 0.01) and learning burnout (r = -0.162, p < 0.01). In contrast, rejection and denial, as well as overprotection and interference, are positively correlated with ACEs (r = 0.576, p < 0.01; r = 0.263, p < 0.01) and learning burnout (r = 0.041, p < 0.01; r = 0.056, p < 0.01).

SEM was established in this study to examine the relationships among various parenting styles, ACEs, learning burnout, and depression ( Table 3 , Figure 3 ). The results indicate that the model fit indices met the acceptable standards: χ²/df = 8.689, GFI = 0.955, AGFI = 0.938, CFI = 0.923, NFI = 0.914, IFI = 0.923, and RMSEA = 0.049.

The standardized path coefficients (β) from the SEM model are summarized in Table 4 . Statistically significant were found from various parenting styles to ACEs, and from ACEs to depression (Rejection and Denial [RD]: β = 0.638, Emotional Warmth and Understanding [EWU]: β = -0.107, Overprotection and Intrusion [OI]: β = -0.226, p < 0.05; ACEs to depression: β = 0.151, p < 0.05). Similarly, the paths from different parenting styles to learning burnout and from learning burnout to depression were also significant (RD: β = -0.173, EWU: β = 0.175, OI: β = -0.213, p < 0.05; learning burnout to depression: β = 0.230, p < 0.05). However the direct effects of different parenting styles on depression and the path from ACEs to learning burnout were not statistically significant (RD: β = 0.017, EWU: β = 0.029, OI: β = -0.006, p > 0.05; ACEs to learning burnout: β = 0.042, p > 0.05).

Further assessment of the mediating effects of ACEs and learning burnout on the relationship between parenting styles and depression was conducted through bootstrap resampling ( Table 5 ). The path coefficients from parenting styles characterized by rejection and denial, emotional warmth and understanding, and overprotection and interference to depression via ACEs were 0.305, -0.047, and -0.094, respectively (p < 0.05). These results indicate that ACEs significantly mediates the relationship between various parenting styles and depression, thereby supporting the validity of Path 1 in Hypothesis 1. Additionally, the path coefficients from the aforementioned parenting styles to depression through learning burnout were -0.127, 0.118, and -0.135, respectively (p < 0.05). This suggests that learning burnout also significantly mediates the relationship between different parenting styles and depression, confirming the validity of Path 2 in Hypothesis 1. However, the mediating effects of ACEs and learning burnout on depression through parenting styles characterized by rejection and denial, emotional warmth and understanding, and overprotection and interference were found to be non-significant, thereby refuting Path 3 in Hypothesis 2.

To investigate whether there are differences in the pathways through which paternal and maternal parenting styles influence depression, we incorporated both parenting styles into our model. The results indicated that there were no significant differences in the effects of paternal and maternal parenting styles on depression. ACEs and learning burnout served as mediators in the relationship between parenting styles and depression. The path coefficients from ACEs to learning burnout were statistically significant (β = 0.059, β = 0.061; p < 0.05, Tables 6 , 7 ), demonstrating a chain mediation effect between ACEs, learning burnout, and depression for both paternal and maternal parenting styles. This finding disproves Hypothesis 3.

To investigate whether there are differences in the pathways through which paternal and maternal parenting styles influence depression, we incorporated both parenting styles into our model. The results indicated that there were no significant differences in the effects of paternal and maternal parenting styles on depression. ACEs and learning burnout served as mediators in the relationship between parenting styles and depression. The path coefficients from ACEs to learning burnout were statistically significant (β = 0.059, β = 0.061; p < 0.05, Tables 6 , 7 ), demonstrating a chain mediation effect between ACEs, learning burnout, and depression for both paternal and maternal parenting styles. This finding disproves Hypothesis 3.

To further explore whether there are gender differences in the pathways through which parenting styles affect adolescent depression, we separated participants by gender and incorporated them into the model. Our findings revealed that the mediating effect of ACEs between parenting styles and depression did not differ between males and females. However, for female adolescents, parenting styles characterized by rejection and denial, as well as excessive protection and interference, positively predicted the occurrence of depression through the mediating effect of learning burnout (β = -0.183, β = -0.148, p < 0.05). Conversely, parenting styles that emphasize emotional warmth and understanding negatively predicted depression (β = 0.140; p < 0.05, Table 8 , Figure 4 ). In male adolescents, only excessive protection was found to influence depression through the mediating role of learning burnout (β = -0.106; p < 0.05, Table 9 , Figure 5 ). Moreover, in female adolescents, parental parenting styles could also influence depression through a chain mediation effect from ACEs to learning burnout, a pathway that was not observed in male adolescents. Therefore, there are indeed differences in the pathways leading to depression resulting from parental parenting styles between genders, thereby supporting Hypothesis 4.