This study aimed to examine the mediation pathway from CM exposure to adolescent NSSI behaviors based on a sample of adolescent patients in a psychiatric setting. The findings supported our hypothesis: CM exposure reveals indirect effects on the severity of NSSI via the mediating effect of DER severity and depressive symptoms. To our knowledge, this is the first investigation of the distal effects from CM to NSSI severity via the chain mediating effect of DER and depression.
In our study, the prevalence of NSSI is over forty percent, girls have higher rates of NSSI, and depressive disorder is the primary psychiatric diagnosis. This is consistent with characteristics in previous adolescent samples (Tuisku et al., 2009; Wang, Liu, Yang, & Zou, 2021). From our results, it is evident that the new generation born in the 2010s reported more emotional abuse and less sexual abuse in childhood, which is consistent with other recent reports in China (Chen et al., 2021; Titelius et al., 2018; Zhang et al., 2013). Nationwide "one-child policy" and the traditional child-rearing practices in China urged the parents to provide their only child with more economic support and safety guards. On the other hand, those who sexually abuse children will be punished in law practice. However, Chinese parents pay more attention to their children's academic performance but less to their emotional needs. In addition, many parents support the traditional belief that boys should be treated strictly for their future development and social roles. In summary, compared with safety or sexual threats, children in Chinese families suffer more emotional abuse and neglect, which may increase depression and emotional dysregulation.
According to previous research results, CM is a distal associative factor of NSSI and a shared risk factor for depression and DER. For the distal risk properties of CM, the time-bound for maltreatment was before the age of 12. So, we speculate that CM mainly affects NSSI through these recent risk factors. The chain mediation model supports our hypothesis, and we found a mediation of the association between CM and NSSI with a significant indirect but no remaining direct effect. Whether CM is understood as a direct risk factor for NSSI is still debated (Brown et al., 2018; Paul & Ortin, 2019). However, CM as a distal factor creates more indirect vulnerability for Mental Disorders, which increases the likelihood of engaging in NSSI (Kaess et al., 2021).
The DER was the strongest mediator, followed by the depressive symptoms. Regardless, our findings are consistent with several previous studies, which showed DER mediates the relationship between CM and NSSI rather than depressive symptoms (Peh et al., 2017; Shenk et al., 2010). Early exposure to abusive or neglectful environments may disrupt children’s development of healthy emotion regulation skills and socioemotional competencies (Maughan & Cicchetti, 2002; Yates, 2009). Individuals with CM experience tend to use more maladaptive strategies, including inhibition and rumination (Weissman et al., 2019), and impaired ability to use adaptive emotion regulation strategies, such as acceptance, reassessment, and problem-solving, which are associated with enhanced positive emotions and better mental health outcomes (Weissman et al., 2019). Without adaptive emotion regulation skills, self-harm behaviors may function as compensatory strategies to cope with overwhelming emotions. Specifically, self-harm may be used to distract oneself from distress and to regain a sense of control and self-efficacy (Lang & Sharma-Patel, 2011). We also proved a potential chain-mediated pathway of DER and depression between CM and NSSI, which may add to our understanding of the relationship between CM and NSSI. The chain mediating of DER and depression was in line with the CM’s role, as it impaired the development of self-regulation on emotional cognitive levels, resulting in poor emotional regulation and a depressogenic attributional style. Significantly, these cognitive and emotional sequelae of CM then increase the risk for later development of depression symptoms (Huh, Kim, Lee, & Chae, 2017; Schierholz, Krüger, Barenbrügge, & Ehring, 2016) and finally contribute to an increasing possibility of NSSI (BaidenStewart & Fallon, 2017).
The above findings potentially align with the biological conceptual model of NSSI (Kaess et al., 2021). Chronic child abuse and neglect lead to alterations in the hypothalamic-pituitary-adrenal (HPA) axis (Kuhlman, Chiang, Horn, & Bower, 2017), brain structure, and function (Teicher, Samson, Anderson, & Ohashi, 2016). These neuroimaging findings overlapped with those of NSSI (Ando et al., 2018; Auerbach, Pagliaccio, Allison, Alqueza, & Alonso, 2021; Schreiner et al., 2020),which are centrally involved in emotion regulation and expression (Kaess et al., 2021) including the anterior cingulate gyrus (ACC ) (Ando et al., 2018), amygdala (Cullen et al., 2020), prefrontal cortex (PFC) and the hippocampus (Dahlgren et al., 2018; Lupien, McEwen, Gunnar, & Heim, 2009). Therefore, we speculate that early exposure to CM impairs the emotion regulation circuit of the brain through environmental-biological interactions in long-term adolescent development, causing DER and depression. Then, adolescents may adopt NSSI as a coping strategy for regulating aversive emotional experiences.
Our findings also have some clinical implications. First, our results contribute to the understanding that CM and NSSI are common among Chinese adolescents with psychiatric disorders. Many adolescents feel reluctant to talk about their CM or NSSI experiences in face-to-face settings. Hence, a mixed battery of self-reports and assessments by physicians may be more suitable in Chinese culture. Second, the distal risk factors (i.e., CM) and proximal risk factors (especially DER) might work together to induce the onset of NSSI. So, assessing DER and depressive symptoms in adolescents with NSSI behaviors is also of practical importance, and we should enhance healthy emotion regulation strategies. Current interventions facilitating healthy emotion regulation might help modify maladaptive cognitions and behaviors (e.g., Dialectical Behavior Therapy, DBT) (Adrian et al., 2019; Tebbett-Mock, Saito, McGee, Woloszyn, & Venuti, 2020). However, more study is needed as research on NSSI prevention is preliminary.