To (i) describe how the deep brain reorienting (DBR) theory can be applied in understanding the development of dissociative identity disorder (DID) and (ii) describe the implementation of the DBR method in two single cases with clients with DID.

This study aimed to assess the effectiveness of deep brain reorienting psychotherapy (DBR) related to the DBR theory as a lens of understanding of the development and treatment of DID, exemplified with two single-case vignettes of clients presenting DID. In the first part of the paper, the theory of DBR is briefly discussed in relation to the development of DID, a condition where severe relational trauma and adjacent childhood traumatisation is hypothesized to be connected to the development of the symptomatology. In the second part, two single-case studies with two DID-clients diagnosed with SCID-D aim to provide initial evidence of how clients with DID experienced and responded to DBR therapy as part of longer phase specific therapies. The client of case I was treated with 30 DBR sessions and the client of case II was treated with 70 DBR sessions. Their pre- and post-DBR treatment measures consisted of instruments to measure PTSD and complex PTSD symptoms, psychoform and somatoform dissociation, general symptomatology, and access to positive states of mind. The outcome measures were assessed through percentage of nonoverlapping data (PND) a nonparametric measure used to assess the effectiveness of interventions in single-case experimental designs (SCEDs). The clients also provided verbal and written statements regarding their experiences during and after the DBR intervention.

After the introduction of DBR in their therapies, when measured by the posttraumatic checklist(PCL-5), the international trauma questionnaire (ITQ), the somatoform dissociation questionnaire (SDQ-5), the Dissociative Experiences Scale II (DES-II), the DES-taxon (DES-T), the Symptom Checklist–90 revised (SCL–90-R), the symptomatology of client I was significantly lowered on all measures apart from the SDQ-5 when analysed with PND. For client II the measurements on PCL-5, SDQ-5 and SCL-90-R were significantly lowered. Their self-assessed positive states of mind, measured with the PSOM-scale, were heightened. Both clients expressed that DBR was a valuable treatment modality through their summarized verbal and written statements.

After 30 respectively during 70 DBR sessions, the clients' dissociation and comorbid symptoms decreased significantly, as measured by self-assessments measures and analysed with PND. Thus, a preliminary cautious enthusiasm is reasonable. Clients with DID may benefit from DBR. Future research is required to address generalizability to a larger population of dissociative clients. To examine whether DBR can be a treatment of choice for highly dissociative clients, including DID, pilot studies followed by RCTs on the efficacy of DBR in treatment of dissociative disorders are warranted. Deepened phenomenological and neuroscientific assessments to verify the feasibility and change agency of DBR in treatment of dissociative disorders are asked for.