In the current cross-sectional study, we examined the mediating effect of body connection on the relationship between traumatic childhood experiences and impairments in personality functioning in a heterogenous sample of individuals from Germany and Chile.
Confirming previous research (see Back et al., 2022 for a review) and our a priori hypothesis, traumatic childhood experiences were significantly associated with impairments in personality functioning. For the first time the current data revealed that 26% of variance in personality functioning can be attributed to childhood trauma, emphasizing their central role for mental health. Interestingly, 60% of this effect could be explained by reduced body connection, primarily through higher levels of body dissociation, and to a lesser extent, lower levels of body awareness. Our exploratory analyses suggest that this holds true for both domains of personality functioning, with body dissociation (and, to a much lesser extent, body awareness) explaining 64% of the variance in self functioning and 55% of the variance in interpersonal functioning attributed to traumatic childhood experiences. Building upon previous studies from our group (Schmitz et al., 2021; Schmitz et al., 2023) and others (Schaan et al., 2019; Schulz et al., 2022), the current data offer additional evidence for a critical role of body dissociation in the interaction between traumatic childhood experiences and impairments in personality functioning.
Our mediation analyses consistently identified body dissociation as a substantial and significant mediator in the relationship between traumatic childhood experiences and impaired personality functioning. The effect of body dissociation appeared to be much more pronounced than the nevertheless statistically significant mediating effect of body awareness, which is consistent to previous findings of Schmitz and colleagues (2021 and 2023). In these previous studies, it was found that body dissociation fully mediated the association between early trauma and emotion dysregulation, which is an important subdomain of self functioning, in individuals with BPD (Schmitz et al., 2021), PTSD, MD, SSD, and healthy controls (Schmitz et al., 2023). Interestingly, the latter study additionally revealed that behavioral indicators for interoceptive accuracy in a Schandry heartbeat perception task did not significantly mediate the association between early trauma and emotion dysregulation.
So, what makes body dissociation so distinctive? Body dissociation encompasses the disrupted integration between bottom-up bodily and top-down mental processes. It thus goes beyond mere representation, awareness, and perception of bodily signals. Rather than that, our results suggest that the non-attendance and/or avoidance of bodily sensations, and their integration in higher-order emotional and cognitive processes, might be relevant in the development of impaired self and interpersonal functioning in the context of childhood trauma. More pronounced body dissociation is indicative of lower integration of aversive body sensations in emotional states (Price & Thompsom, 2007) and may serve as a proxy for a reduced ability to perceive interoceptive signals (e.g., in terms of habitual disregard or non-attendance of signals from the body; Khoury et al., 2018). For BPD, a model proposed by Löffler and colleagues (2018) suggests that experiences of early trauma may result in impairments between the coupling of internal bodily signals with emotional states and decision-making. It is conceivable that internal bodily signals might fail to capture attention or be disregarded as irrelevant or even perceived as dangerous in affected individuals. Eventually, these processes may promote impairments in the development of central capacities related to self functioning, such as deficits in self-regulation and identity diffusion. Impairments in interpersonal functioning, including deficits in empathy and an inability to develop and maintain intimate relationships, might be a consequence or associated impairment (see Löffler et al., 2018). The current findings, along with those by Schmitz et al. (2023), may suggest that this model applies more generally to early trauma-associated impairments in personality functioning.
The close link between body connection and psychological (dys)function also indicates new approaches in therapy. Body-oriented therapeutic treatments have gained attention in the past decade for various mental disorders, including those with high prevalences of early trauma. Additionally, several studies have explored the efficacy of treatments aimed at improving interoceptive processes, including sensitivity to bodily signals. Despite the mixed results presented by meta-analyses summarizing methodologically and qualitatively very heterogenous investigations, promising outcomes were found amongst others for individuals with PTSD (Heim et al., 2023). Many treatment programs for individuals with early trauma and/or impaired domains of personality functioning already incorporate body-oriented modules, such as body scans, mindful breathing, yoga, or others (e.g. Dialectic-Behavioral Therapy, Linehan, 2014; new approaches as proposed by Laaricchiuta et al., 2023; Price & Hooven et al., 2018).
Based on the current findings, one might suggest interventions that specifically target the integration of body signals into cognitive and emotional processes beyond their mere perception for individuals with early trauma. Such developments align with early embodiment theories rooted in the work of Damasio and colleagues (e.g., 1996). According to these theories, bodily information can be viewed as somatic markers for specific emotions, thereby aiding intuitive behavior and decision-making.
Based on this, therapies in extended realities (XR, including virtual reality (VR) and augmented reality (AR)) could also be a completely new approach. XR has already been used successfully in exposure therapy with trauma and anxiety patients (Morina et al., 2015; Morina et al., 2023). In addition, it has already been shown that presenting one's own body using virtual avatars (virtual representation) can change body perception (Döllinger et al., 2023; Wolf et al., 2020; Döllinger et al., 2023). The altered body perception in VR can also influence higher cognitive processes such as self-evaluation and evaluation of others (Praetorius et al., 2020; Ratan et al., 2020). To explain these phenomena, theories of embodiment are also used and transferred to the virtual space (Maister et al., 2015). Here, too, a multisensory integration of bottom-up and top-down factors is assumed (Waltemate et al., 2018). The mechanisms for the emergence of virtual body ownership therefore appear to be similar to those in the physical world. The advantage of XR, however, is that the virtual body can be changed and thus also the perception of the body (Wienrich et al., 2021). In addition, out-of-body experiences can help to leave the body, which may have a negative connotation, and have new positive experiences (Döllinger et al., 2024). The implementation of XR as a therapy tool in the treatment of body connection problems in individuals’ memories of early trauma may therefore be a promising focus of future research.
Further experimental research is needed to investigate whether changes in body dissociation during trauma-associated, emotionally arousing situations predict personality functioning, before causal conclusions may be drawn. With regard to psychotherapy, a positive effect of Eye Movement Desensitization and Reprocessing (EMDR), an established trauma-focused treatment, was found on the coupling in the heart-to-brain-direction in women with breast cancer and PTSD (Malandrone et al., 2024).
Limitations and future directions
Despite some intriguing advantages of the current study, such as the relatively large and heterogeneous sample recruited from the general population and psychiatric treatment facilities in two different countries (and continents), some limitations need to be mentioned. First and foremost, our cross-sectional, correlational, mono-method design does not allow for causal inference. The use of mediation models on cross-sectional data has been criticized as it may lead to biased estimates that may not align with findings from longitudinal studies (Maxwell & Cole, 2007). However, other authors advocate for employing a variety of designs to test for mediation (Imai et al., 2011) instead of solely relying on complex longitudinal mediation designs. We employed mediation models as recommended by Hayes (2013) and MacKinnon et al. (2007) to cultivate hypothesis-generating knowledge in an exploratory manner. This approach may be particularly advantageous when studying individuals who have experienced trauma in the past, given the anonymity of assessment and the reduced emotional burden associated with brief online assessments compared to extensive longitudinal or experimental study designs. Nevertheless, our results should be viewed as a preliminary proposed model, and further experimental and longitudinal research is warranted to conclusively test for causality. Secondly, despite the substantial variance explained by body connection, the partial mediation effect suggests that other processes not depicted in our model are also involved in the relationship between early trauma and impaired personality functioning. This may be expected due to the complexity of both factors. Further mediating processes may include transdiagnostic protective and resilience factors, such as social support (Seitz et al., 2022). In light of evidence on transdiagnostic models of psychopathology, traumatic childhood experiences are likely to represent a differential susceptibility factor. These experiences might amplify an individual’s vulnerability to stressors and the subsequent emergence of psychopathology, while also enhancing the sensitivity to improvements in stress regulation in population-based samples (Albott et al., 2018). Given that personality functioning encompasses the entire spectrum from none to severe impairment, it may be important to include resilience and protective factors that promote sensitivity to improvement in everyday (early) stress regulation, especially in samples characterized by lower clinical symptom severity (as expected in a community or population-based samples). This may particularly apply to the current sample, where levels of personality functioning were rather below to the average values expected within a representative general population sample (Spitzer et al., 2021).
Thirdly, we solely relied on self-report measures (and referral by clinicians for most of the Chilean clinical sample), which may limit the validity of the clinical characterization of our samples. Additionally, the retrospective reporting of childhood trauma may be influenced by recall bias and state-dependent memory. Indeed, retrospective and prospective reports of childhood trauma has been elicited as two separate constructs, based upon latest meta-analytic evidence (Baldwin et al., 2019). However, the Childhood Trauma Questionnaire (CTQ) demonstrates equivalent psychometric properties compared to interview-based assessments (Seitz et al., 2022), therefore encouraging its validity of mapping retrospective childhood trauma.
Fourthly, we cannot conclusively demonstrate that our effects on body dissociation are independent of other, more general forms of dissociation. However, Schmitz and colleagues (2021 and 2023) were able to show that the effects of bodily dissociation remain robust even when levels of trait dissociation were statistically controlled for. Lastly, we cannot conclude the possibility that other psychopathological symptoms, which are also closely related to disturbed body processing (such as eating disorders; for review see, Arberg et al. 2011), may have influenced the association with personality impairments. Additionally, it is not possible to make general conclusions about causal directions between personality functioning and psychopathological symptoms, as this is beyond the scope of the current study. Although preliminary evidence suggests that personality functioning may be a transdiagnostic process of vulnerability for and/or against psychopathology (Krakau et al. 2021, Freier et al., 2022; d’Huart et al., 2022; Kerber et al., 2023), causal evidence for the direction of effects is lacking. A bi-directional influence of personality functioning and psychopathological symptoms seems likely, thereby underscoring the importance of controlling for additional psychopathological symptoms, such as eating disorder symptoms (Arberg et al. 2011), when examining the role of body connection on personality functioning.