The World Health Organization defines child maltreatment as “the abuse and neglect that occurs to children under 18 years of age. It includes all types of physical and/or emotional ill-treatment, sexual abuse, neglect, negligence, and commercial or other exploitation, which results in actual or potential harm to the child’s health, survival, development, or dignity in the context of a relationship of responsibility, trust, or power.” [1] Childhood trauma, a global phenomenon, has been extensively linked to adverse psychiatric outcomes in adulthood [2]. Individuals exposed to childhood abuse or neglect are at heightened risk of developing a range of psychiatric disorders, including major depressive disorder (MDD), posttraumatic stress disorder, bipolar disorder, dissociation, and substance use disorders, as well as engaging in high-risk behaviors [3-7]. Notably, childhood maltreatment has been identified as a significant risk factor for lifelong depression, contributing to the severity and chronicity of MDD [8]. Patients with MDD who have experienced childhood trauma exhibit a higher frequency of depressive episodes and an increased incidence of suicidal behavior [9,10]. Evidence indicates that among patients with recurrent depression, those with a history of childhood trauma demonstrate an earlier onset of MDD, with physical neglect and emotional abuse serving as significant predictors of the first depressive episode [11]. Furthermore, individuals with MDD and a history of childhood trauma exhibit more severe symptomatology, poorer clinical outcomes, and increased resistance to treatment compared to those without such histories [12].

Rumination is characterized by a persistent focus on negative moods, along with their potential causes and consequences, particularly feelings of sadness and depression [13]. It is well-established that ruminative thinking centered on depressive symptoms can exacerbate both the duration and intensity of these symptoms, contributing to a more persistent depressive state [14]. Research suggests that individuals with a history of adverse childhood experiences may be predisposed to ruminative thinking [15]. Exposure to childhood traumatic events may lead to repetitive negative thought patterns as a maladaptive strategy to regulate emotional distress. Such individuals often engage in rumination as a means of attempting to comprehend and exert control over the distressing aspects of their experiences [16].

Existing literature identifies the mediating role of factors such as rumination, emotion regulation, and alexithymia in the association between childhood trauma and MDD [17-19]. It has been demonstrated that childhood trauma exacerbates persistent anxiety and rumination, thereby influencing depressive symptomatology [19]. However, despite these findings, there is a notable lack of studies investigating the mediating effect of rumination on the relationship between childhood trauma and MDD in clinical populations.

Given these considerations, the present study aims to examine the mediating role of rumination in the relationship between childhood trauma and depression severity. Understanding these mechanisms may provide insights into the cognitive processes through which early adverse experiences contribute to depressive symptoms and inform the development of targeted prevention and intervention strategies.

The average age of the participants included in the study was 32.51±9.13 years, with 63.2% (n=117) being female. There was no statistically significant difference found in terms of sex (χ²=0.028, p=0.866) and age (t=0.946, p=0.345). However, statistically significant differences were observed in duration of education (U=1,831, p<0.001), employment status (χ²=40.735, p<0.001), and marital status (χ²=12.805, p=0.002). A comparison of other sociodemographic variables between the two groups is presented in Table 1.

The analysis of the correlations among the participants’ scores on the BDI, RTSQ, and CTQ-33 is presented in Table 2. A positive and significant correlation was found between the total score of the CTQ-33 and both the total score of the BDI and the total score of the RTSQ. Additionally, a positive and statistically significant correlation was established between the total score of the BDI and the total score of the RTSQ (r=0.671, p<0.001).

The binary logistic regression analysis conducted on parameters (age, sex, RTSQ, CTQ-33) that may affect the development of depression yielded statistically significant results (χ²(9)=102.613, p<0.001). The model explained 56% of the variance in depression status as indicated by the Nagelkerke R² coefficient and correctly categorized 79% of the participants overall. The model’s sensitivity was 78%, and specificity was 79%. Among the independent variables, the RTSQ (p<0.001), Physical Abuse (p=0.038), Physical Neglect (p=0.004), and Emotional Neglect (p=0.050) were found to be significant predictors. The data from the logistic regression analysis demonstrating the predictive power of these variables regarding the presence of depression are presented in Table 3.

The mediation model demonstrated the strength of the direct relationship between childhood trauma and depression, as well as the strength of the indirect relationship mediated by rumination. The model exhibited adequate fit indices (chi-square to degrees of freedom ratio=3.273, comparative fit index=0.944, root mean square error of approximation=0.079). Similar to the baseline model, all related variables included in the mediation model had medium to high loadings. Rumination was predicted by childhood trauma (standardized coefficient=0.44, p<0.001) and was a predictor of depression (standardized coefficient=0.56, p<0.001). The mediation model highlighted the significance of the indirect pathway indicating the mediating relationship of rumination between childhood trauma and depression in terms of predictive and outcome variables.

The baseline model indicated a significant direct effect between the CTQ-33 and the BDI (p=0.01, b=0.50), while the mediation model demonstrated both direct (p=0.011; b=0.24; 95% confidence interval, CI [0.12-0.36]) and indirect effects (p=0.003, b=0.25, 95% CI [0.19-0.32]) between the CTQ-33 and the BDI through the RTSQ. The total effect in the model was 0.48, with a direct effect of 0.24 and an indirect effect of 0.25. The mediation model is shown in Figure 1. The Sobel test conducted to evaluate the significance of the mediation effect yielded a relatively high value (4.07), indicating that the mediating role of rumination was statistically significant.

The present study aimed to examine the potential mediating role of rumination in the relationship between childhood trauma and depression severity among patients with MDD. The findings suggest that childhood trauma may be associated with higher depression severity, potentially through increased levels of rumination. Specifically, rumination, physical abuse, physical neglect, and emotional neglect were found to be significantly associated with depression severity. These results highlight the possible contribution of ruminative cognitive processes in the link between early adverse experiences and depressive symptoms, underscoring the importance of addressing rumination in clinical interventions.

Mandelli et al. [26] reported that childhood neglect is the strongest predictor of depressive symptoms. Their meta-analysis also found strong associations between emotional, sexual, and physical abuse, as well as domestic violence, and increased risk of depression. In clinically diagnosed populations, neglect had a greater impact on depression risk than sexual or physical abuse, whereas in community-based samples, emotional abuse demonstrated the greatest effect. Humphreys et al. [27] conducted a meta-analysis demonstrating that all forms of childhood trauma are significantly correlated with elevated depression scores and an increased risk of meeting diagnostic criteria for MDD. Notably, emotional abuse and emotional neglect were identified as the childhood traumatic experiences most strongly associated with depression. The study also reported that the effect size of the relationship between emotional abuse and depressive symptoms was greater in child and adolescent samples compared to adult populations, suggesting a potential attenuation of this relationship with increasing age. Spinhoven et al. [28] identified emotional neglect as a significant predictor of depressive and anxiety disorders. Similarly, a Turkish validation of the CTQ-33 found that emotional neglect predicted depression, whereas the excessive control subdimension did not. The study also highlighted the correlation between excessive control, emotional neglect, and emotional abuse [23]. A gender-specific analysis by Lee et al. [8] revealed that physical abuse significantly contributed to depressive symptoms in males, whereas emotional abuse had a pronounced effect in females. Moreover, emotional neglect was found to predict depressive symptoms across both genders. This study identified physical abuse, emotional neglect, and physical neglect as significant predictors of depression, while emotional abuse was not a significant predictor. Mandelli et al. [26] highlighted the challenge of clearly distinguishing emotional abuse from emotional neglect, with Çelik and Hocaoğlu [29] noting that emotional abuse and neglect frequently co-occur, present in approximately 90% of physical abuse and neglect cases. The difficulty in detecting emotional abuse, the use of a clinical rather than community sample, and the potential weakening of the association between emotional abuse and MDD over time may explain the lack of a significant predictive relationship between emotional abuse and MDD in this study. Additionally, it is important to consider that adults may normalize childhood emotional abuse within their cultural context, attributing it to personality traits or familial parenting practices, which could affect the interpretation of these findings. Hovens et al. [12] reported that sexual abuse was not consistently associated with depression as a significant predictor. Despite the known prevalence and long-term consequences of sexual abuse, it is often underreported due to factors such as feelings of shame, fear of disbelief, the desire to protect the perpetrator, and threats [30]. Similar to the study by Hovens et al. [12], sexual abuse did not emerge as a significant predictor of depression severity, which may partly reflect participants’ reluctance to disclose such experiences for the reasons mentioned above. OP-OC is a maladaptive parenting behavior characterized by excessive involvement of caregivers in their children’s activities [31]. Overprotective and controlling parenting has been shown to have negative effects on children’s mental health, including increased anxiety and depression [32]. Parental overcontrol has been found to be positively correlated with rumination and depression levels [33]. Consistent with previous literature, our study found significant positive correlations between OP-OC levels and both depression and rumination. These findings support the reported detrimental effects of OP-OC parenting behaviors on individuals’ psychological functioning and suggest that overprotective and controlling parenting may increase the risk of rumination and depressive symptoms.

The existing literature demonstrates that individuals exhibiting higher levels of ruminative responses to depressive states are more likely to experience exacerbation of depressive symptoms over time, even when accounting for baseline symptomatology [34]. In a longitudinal study, Spasojević and Alloy [35] further substantiated this association by identifying rumination as a significant predictor of MDD. Their findings aligned with prior research, indicating that ruminative thinking functions as a risk factor for the onset and persistence of MDD. Additionally, it has been posited that the predisposition toward rumination is more prevalent among adults who encountered adverse childhood experiences, such as traumatic life events or parental overcontrol [15]. Mansueto et al. [16] suggested that individuals exposed to childhood trauma may be inclined to engage in repetitive negative thinking, such as rumination, which could serve as an ineffective coping strategy for dealing with negative emotions and psychological distress. It has been proposed that this process might reflect an attempt to make sense of and exert some perceived control over distressing life circumstances. Within the framework of the metacognitive model of MDD, metacognitive beliefs arising from depressive emotions and thoughts are believed to initiate a self-perpetuating cycle of ruminative thinking [36]. A sustained focus on depressive symptoms is thus associated with the increased duration and intensity of these symptoms, contributing to the chronicity of the disorder [14]. Collectively, these findings suggest that rumination constitutes a key factor in both the etiology and maintenance of MDD psychopathology. In accordance with prior literature, the present study identified significant positive correlations between rumination and depressive symptom severity, as well as between rumination and experiences of childhood trauma across all subscales.

However, the current study has several limitations that should be taken into account. Its cross-sectional design, coupled with reliance on self-report measures, raises concerns about recall bias, given that certain information was based on participants’ retrospective recollection. Additionally, the relatively small sample size and limited number of male participants limit the generalizability of the findings across genders and to broader populations. The inherent subjectivity of the items assessing emotional abuse and neglect within the CTQ-33 represents an additional limitation. Specifically, these items rely on participants’ personal interpretations of their experiences, which may vary considerably based on individual perception, memory accuracy, and cultural or social factors. Furthermore, responses may be influenced by social desirability bias, emotional avoidance, or difficulties in recognizing subtle forms of emotional maltreatment. Similarly, sexual abuse may be underreported due to stigma, feelings of shame, or fear of disclosure, potentially leading to an underestimation of its prevalence and impact in the study sample. Another limitation lies in the study’s inability to differentiate between individuals exposed to isolated traumatic events and those subjected to multiple forms of trauma. The study also does not address critical variables, such as the proximity of the perpetrator to the victim, the age of exposure, and the duration of neglect or abuse, all of which could significantly impact the findings. Additionally, the study was conducted in a single-center setting, which may further limit the generalizability of the results. These methodological constraints necessitate careful interpretation of the results and underscore the need for further longitudinal research to elucidate these associations comprehensively.

Research on the mechanisms linking childhood trauma to adult psychiatric outcomes remains limited. Considering the extended latency between childhood trauma and the onset of MDD in adulthood, it is likely that multiple mediating factors contribute to this relationship [37]. Similar to previous studies, our results indicated that rumination may be an important mediating factor in the pathway between childhood trauma and depression severity in adulthood [19,38]. A major strength of this study is the exclusion of participants using psychotropic medications, as these agents have been shown to influence rumination levels [39]. This methodological rigor enhances the internal validity of our findings and supports the robustness of the observed associations.

In conclusion, the findings of this study suggest that childhood trauma is associated with depression severity and that rumination may exacerbate the direct impact of such traumatic experiences. These results underscore the importance of developing targeted therapeutic interventions for individuals with a history of childhood trauma, with particular attention to addressing rumination as a mediating factor in the progression of psychopathological conditions. It is crucial to incorporate adaptive cognitive strategies in clinical settings to mitigate the effects of rumination on mental health outcomes. Further longitudinal research is warranted to elucidate the complex interplay between childhood trauma, rumination, and the emergence of diverse psychopathologies.