Moreover, it is associated with high psychosocial and socioeconomic costs (Soeteman et al., 2008).

The strong association between trauma, dissociation and borderline traits may be interpreted from the perspective

Bowlby (1982Bowlby, J. (1982). Attachment and loss. Volume 1: Attachment (2nd ed.). London: Hogarth Press. [Google Scholar]) established the link between a child's development and the quality of the relationship with caregivers. An absence of feeling held in mind and a lack of secure attachment can have a traumatic impact on body and mind (Bartenieff & Lewis, 1980Bartenieff, I., & Lewis, D. (1980). Body movement: Coping with the environment. New York, NY: Gordon and Breach. [Google Scholar]). ‘The mother infant relationship is mediated through eye contact, rhythm, sound, reciprocity, synchrony and the sensory-motor experience of holding’ (Meekums, 2002Meekums, B. (2002). Dance movement psychotherapy: Creative therapies in practice. London: Sage. [Google Scholar], p. 33). Nurturing behaviour from a caregiver helps to preserve a child's emotional and physical balance. Rothschild (2000Rothschild, B. (2000). The body remembers: The psychophysiology of trauma and trauma treatment. London: W.W Norton. [Google Scholar]) suggests that the impact of trauma on psychophysiology can lead to an avoidance of eye contact between the child and its caregiver and may be linked with feelings of shame and separation distress.Loewenstein (1993Loewenstein, R. J. (1993). Dissociation, development and the psychobiology of trauma. Journal of American Academy of Psychoanalysis, 21, 581–603. Retrieved from http://psycnet.apa.org/psycinfo/1994-21476-001. [PubMed], [Google Scholar]) states that dissociation is the mind's attempt to flee when the body freezes; movement, therefore, may provide a healing path for clients who have experienced trauma (Steckler, 2006Steckler, L. H. (2006). Somatic soulmates. Body, Movement and Dance in Psychotherapy: An International Journal of Theory, Research and Practice, 1(1), 29–42. 10.1080/17432970500410960. [Taylor & Francis Online], [Google Scholar]). Movement work can enable clients to engage with flow in effort (Laban & Lawrence, 1947Laban, R., & Lawrence, F. C. (1947). Effort. London: MacDonald & Evans. [Google Scholar]), improving their capacity to think and stay in contact with their emotional experience.

AttachmentDeprivation of a reliable, attuned caregiver to provide a safe base for feelings being contained and fed back to the child (Fonagy & Bateman, 2004Fonagy, P., & Bateman, A. (2004). Psychotherapy for borderline personality disorder: Mentalisation based treatment. Oxford: Oxford University Press. [Google Scholar]; Kernberg, 2004Kernberg, O. (2004). Aggressivity, narcissism and self destructiveness in the psychotherapeutic relationship. London: Yale University Press. [Crossref], [Google Scholar]) can result in what Adshead (1997Adshead, G. (1997). Written on the body: Deliberate self-harm and violence. In E. V.Welldon & C.van Velsen (Eds.), A practical guide to forensic psychotherapy (pp. 110–114). London: Jessica Kingsley. [Google Scholar]) describes as an increased tendency to dissociate, an impaired capacity to put emotions into words and dysregulation of affect control. Feelings can be split off in order to cope with the need for care from the mother, despite the awareness of not having ones needs met. Loss, separation and trauma can also lead to insecure attachment formation, the failure of developing a ‘protective shield’ (Freud, 1920/2001Freud, S. (2001). The standard edition of the complete works of Sigmund Freud, Volume XVIII (1920–1922): Beyond the pleasure principle, group psychotherapy and other works. London: Vintage (Original work published 1920). [Google Scholar], p. 27) being the result of cumulative trauma (Khan, 1963Khan, M. R. (1963). The concept of cumulative trauma. The privacy of self (pp. 42–48). New York, NY: International Universities Press. [Google Scholar]). Bowlby (1988Bowlby, J. (1988). A secure base: Clinical applications of attachment theory. London: Routledge. [Google Scholar]) saw attachment behaviour as continuing throughout life, during anxiety and stressful times. In adulthood, ambivalent attachment, as seen in BPD clients, can lead to over responsiveness in close relationships, jealousy and consequently rejection. The relational framework of attachment theory provides a social and developmental perspective for understanding patterns of interpersonal and intergenerational pathology (Fonagy & Bateman, 2004Fonagy, P., & Bateman, A. (2004). Psychotherapy for borderline personality disorder: Mentalisation based treatment. Oxford: Oxford University Press. [Google Scholar]).Dance movement psychotherapy (DMP) seeks to engage patients through a therapeutic relationship. The therapist can provide containment through kinaesthetic empathy, attunement and awareness of ones own countertransference experiences (Warnecke, 2009Warnecke, T. (2009). The borderline relationship. In L.Hartley (Ed.), Contemporary body psychotherapy: The Chiron approach (pp. 194–211). London: Routledge. [Google Scholar]). Homann (2010Homann, K. B. (2010). Embodied concepts of neurobiology in dance/movement therapy practice. American Journal of Dance Therapy, 32, 80–99. [Crossref], [Google Scholar]) presents how DMP interventions foster embodied, attuned connections using physical and emotional aspects of the self. Research on neurological functioning of mirror neurons provides insight to the underpinning of body–mind domains. Mirror neurons become activated not only through witnessing movement but also through voice, touch, proprioception and other sensory modalities (Sherwood, 2011Sherwood, D. N. (2011). The embodied psyche: Movement, sensation, affect. In R. A.Jones (Ed.), Body, mind and healing after Jung: A space of questions (pp. 62–78). East Sussex: Routledge. [Google Scholar]). This brain research suggests that one can experience activation of equivalent neurons by observing movement of another. Mirror neurons are a source of inter-subjective empathy (Gallese, 2003Gallese, V. (2003). The roots of empathy: The shared manifold hypothesis and the neural basis of intersubjectivity. Psychopathology, 36, 171–180. 10.1159/000072786. [Crossref], [PubMed], [Web of Science ®], [Google Scholar]) and help to explain how mirroring and embodiment in DMP therapeutically benefit patients (Berrol, 2006Berrol, C. F. (2006). Neuroscience meets dance/movement therapy: Mirror neurons, the therapeutic process and empathy. The Arts in Psychotherapy, 33, 302–315. 10.1016/j.aip.2006.04.001. [Crossref], [Web of Science ®], [Google Scholar]). Empirical research is needed in this area for further evidence of effectiveness (McGarry & Russo, 2011McGarry, L. M., & Russo, F. A. (2011). Mirroring in dance/movement therapy: Potential mechanisms behind empathy enhancement. The Arts in Psychotherapy, 38, 178–184. [Crossref], [Web of Science ®], [Google Scholar]).

Dissociation is a complex phenomenon, which occurs in various clinical conditions, including dissociative disorders, (complex) post-traumatic stress disorder (CPTSD, PTSD), and borderline personality disorder (BPD). Traumatic stress is considered an important risk factor, while the etiology of dissociation is still debated. Next to traumatic experiences, temperamental and neurobiological vulnerabilities seem to contribute to the development of dissociation. Stress-related dissociation is a prevalent symptom of BPD, which may interfere with psychosocial functioning and treatment outcome

The effects of dissociation on psychosocial functioning may depend on the larger psychopathological context, e.g., emotional dysregulation and identity problems [47, 48]. In BPD, stress-related dissociation is a core symptom, closely linked to other features of the disorder [1, 49]. Up to 80% of patients with BPD report transient dissociative symptoms, such as derealization, depersonalization, numbing, and analgesia [1, 50]. The severity of dissociation is correlated to the severity of traumatic experiences [23, 28, 29]. While trauma is an important risk factor for the etiology of BPD in individuals with genetic, temperamental neurobiological vulnerabilities [51,52,53,54,55], non-trauma related pathways are also involved [56, 57]. Dissociation in BPD is closely linked to emotion dysregulation, disturbed identity, and relationship problems.Emotion dysregulation includes a tendency to experience intense overwhelming emotions. The strength, frequency and intensity of emotional distress was found to increase and decrease along with dissociative symptoms [58]. Dissociation may exaggerate difficulties identifying emotions [59]. During emotional distress, patients with BPD show impulsive decision making [60] and often use maladaptive strategies to regulate their emotions, e.g., non-suicidal self-injury (NSSI) [61, 62]. Terminating states of dissociation can be a strong motive for NSSI [63, 64]. A recent study suggests that dissociation is linked to pain hyposensitivity in patients with acute BPD, but not in those who show remission [65].A novel line of research further suggests that dissociation is linked to reduced body ownership, i.e., the certainty that body parts belong to oneself [66]. In a recent study, female patients with BPD reported significantly lower levels of body awareness and significantly higher levels of body dissociation compared to healthy women. Significant positive correlations between body dissociation, traumatic childhood experiences, and emotion regulation were found [67].Identity disturbances are another core domain of BPD. Individuals with the disorder experience rapid changes in self-image and perceived their identity as incoherent, inconsistent, vague, or fragmented [68,69,70]. They also report chronic feelings of emptiness [71]. Sense of self strongly depends on current self-esteem, which is highly unstable under daily life condition [69, 72]. Identity disturbances in BPD show considerable overlap with dissociative symptoms and may be hard to distinguish [73].Interpersonal disturbances in BPD involve profound mistrust, rejection hypersensitivity, and strong ambivalence between a need for closeness and a need for autonomy [74,75,76,77]. It is crucial to improve the understanding of dissociation in this context. In intimate relationships, dissociation may reduce assertiveness and lead to a subjective detachment from violent behaviour [78, 79]. There is preliminary evidence that dissociation contributes to sexual revictimization after child sexual abuse, when BPD symptoms and emotion regulation are taken into account [80]. However, much more prospective research is needed to understand how dissociation interferes with interpersonal functioning in BPD. For instance, future studies may investigate how dissociation interferes with intimacy, trust, and the processing of both positive and negative experiences in close relationships.

This study considered the role of dissociation and personality fragmentation as psychological factors that might distinguish borderline and personality disorder (BPD) patients, and that might explain why BPD patients have higher levels of other psychiatric symptomatology than those with other personality disorders.

To conclude, psychotic symptoms in BPD patients are often trauma–and stress-related. Therefore, clinicians need to adequately contextualize the patient’s symptoms by investigating trauma-related histories as well as daily stressors that may trigger symptom presentation. Dissociative symptoms such as derealization, depersonalization, and paranoid ideation often disappear when the trigger can be identified or when patients learn to cope with dissociation.