This study aimed to investigate the relationship between ACEs and DSH through the mediating roles of shame and self-disgust. Prior to examining the mediating roles of shame and self-disgust, we investigated the direct relationship between ACEs and self-harm. As shown by our findings, ACEs can be directly linked to self-harm. This finding aligns with previous research. For instance, Hu et al.’s study revealed that the greater the number, duration, and types of maltreatment a child experiences, the higher the future risk of hospitalization due to these DSH behaviors (
38). Research has demonstrated that growing up in environments characterized by poverty, violence, substance abuse, and multiple ACEs is strongly associated with an increased risk of dual harm (self-harm and harm to others) (
39). A study conducted on forensic psychiatric patients reported a widespread prevalence of childhood maltreatment among this group; only 5% (5.7%) of participants reported no emotional abuse in childhood. According to the files, 57.2% of participants reported physical abuse and 20% reported sexual abuse during childhood. Each additional ACE significantly predicted an increased likelihood of NSSI (
40). In a recent meta-analysis conducted by Liu et al., evidence clearly indicates that multiple forms of childhood maltreatment independently and collectively predict NSSI. However, emotional abuse has potentially larger negative effects compared to other types of abuse (
9). In support of these findings, childhood traumas impair children’s ability to develop positive adaptations and, in turn, lead them to adopt defective alternative regulatory and relational strategies such as self-harm (
41). Childhood trauma and various forms of early neglect can produce neurobiological effects that may impair the brain’s ability to control and regulate emotions, making traumatized individuals more prone to impulsivity (
42). A very recent study found that resting-state functional connectivity between the amygdala and the dorsolateral and orbitofrontal cortices is altered in bipolar disorder adolescents with a history of self-harm (
43).
Structural equation modeling results indicated that ACEs had a direct effect on self-harm and an indirect effect on self-harm mediated by shame. This finding is consistent with previous research. Studies have indicated that the childhood environment is significantly associated with feelings of shame. High levels of abuse, in all its forms, accompany more intense feelings of shame (
44). Experiences of poor care during childhood are associated with emotional difficulties, such as shame and self-disgust. In other words, negative family environments that provide little support and positive feedback may enhance the risk of experiencing shame (
45). The results of a meta-analysis in 2019 revealed that feelings of shame following childhood sexual abuse (CSA) significantly impacted psychological effects and trauma symptoms. Overall, studies provide evidence that shame can hinder psychological adjustment after CSA (
46). To explain this finding, it can be argued that children who do not receive affection from their parents may develop the belief that they do not deserve such feelings. This can lead to feelings of inadequacy and defectiveness. Ultimately, these negative emotions can manifest as feeling of shame (
47). In fact, recent research suggests that NSSI behaviors serve, in part, as a way to regulate the experience of shame specifically, as well as a form of self-punishment in response to shame-based cognitions and affect (
23). Evidence suggests that childhood trauma and various forms of early neglect can induce neurobiological effects that may disrupt the brain’s ability to regulate emotions, which may make these individuals more prone to impulsivity (
42). Since these individuals are deprived of opportunities to learn emotion regulation strategies due to early traumatic experiences, they tend to engage in behaviors such as NSSI as a temporary diversion from negative emotions (
48). According to the traumagenic dynamic model of child sexual abuse, negative messages sent to the child regarding the abuse by the perpetrator, the child’s environment, and society often become part of the child’s self-concept, leading to negative self-perceptions and blame and shame. For example, a victim who internalizes such messages may think that they are bad or deserve what happened to them. Blame and shame can increase the risk of adverse life outcomes and suicidal thoughts (
49).
The SEM results also indicated that ACEs have a direct effect on self-disgust and an indirect effect on self-harm, mediated by self-disgust. This finding aligns with previous research. Individuals who have experienced repeated physical or emotional abuse may come to believe they possess hateful qualities and develop self-disgust (
50). In a study in 2010, Rachman demonstrated that post-traumatic cognitive appraisal regarding one’s role in a traumatic event can culminate in the emergence of self-disgust. For instance, an individual may describe experiencing sexual arousal during rape as unpleasant and morally reprehensible and feel repulsed by it. These interpretations can give rise to persistent and maladaptive self-disgust as a result of generalized distorted beliefs (
51). According to Nilsson et al., individuals who engage in self-harm have experienced more childhood maltreatment and possess more negative self-concept content. In this research, emotional abuse was most strongly associated with DSH. Self-disgust showed a significant mediating effect between emotional abuse and the presence of DSH (
28). To explain this finding, it can be argued that childhood abuse can distort a child’s perception of themselves. The child may even believe that they are to blame for being abused, making it difficult to let go of internal guilt and leading to feelings of self-disgust (
52). Similarly, individuals who are abused during childhood may develop negative and pessimistic cognitive views of themselves, the world, and the future. They may believe they were abused because they are bad, guilty, and worthless, leading to self-disgust (
53). In addition to the explanations, individuals with self-disgust report physical sensations such as nausea or illness, avoidance or self-injurious behaviors, and specific beliefs, such as the belief that they have unchangeable repulsive traits or the belief that they can infect others. In situations where they cannot easily forget repulsive aspects such as perceived traits about themselves or traumatic memories, self-disgust may lead them to punish themselves or even attempt to eliminate themselves (
54).
Our findings emphasize the importance of screening for and treating the psychological effects of childhood maltreatment in adults who engage in self-harm, as well as the need for supportive interventions for those who have previously experienced childhood adversity.
5.1. Conclusions
The findings of the present study have important implications for child protection, prevention of DSH and suicide, as well as caregiving practices in emotion regulation, particularly shame and self-loathing. Early identification and intervention are crucial for the early prevention of ACEs. Early intervention as possible for children exposed to childhood trauma may lead to reduced future self-harm. Despite its complexities, this remains an area in which further research is warranted. Furthermore, further research is needed to further confirm the impact of childhood trauma not only on DSH across the lifespan, but also on other mental health outcomes, suicide attempts, and suicide deaths. These findings also highlight the importance of trauma care for individuals seeking treatment for DSH. Trauma-related shame and self-disgust following ACEs could increase DSH. As emotions of shame and disgust may not be openly expressed, interventions addressing DSH by alleviating the negative impacts of these emotions are likely to foster the development of more adaptive coping strategies.
5.2. Limitations
Data collection was conducted online and was accessible. This study relied solely on self-report questionnaires, which may have led to participants withholding accurate responses, and issues such as bias and social approval may have influenced responses. Information regarding childhood trauma was collected retrospectively, and the passage of time may have distorted participants’ memories of these events. The study was conducted cross-sectional, preventing causal inferences. Given that the majority of participants (89%) were female, caution should be exercised when generalizing the findings to the male population. It is suggested that more precise sampling methods be used in the future and that samples be collected in person, if possible. The severity and duration of involvement with self-harm should be considered and examined in data analysis. Further longitudinal research is needed to disentangle the mechanisms that cause DSH. Given the cultural diversity of Iranian society, it is suggested that this research be repeated in different ethnic-cultural samples to increase the generalizability of the results.