Patients diagnosed with complex PTSD (cPTSD) are characterised by having experienced repeated and often prolonged traumatic events; they are described based on specific symptoms which, in addition to those of PTSD, also include difficulty regulating emotions, negative self-image and relationship difficulties (Herman, 1992; Van der Kolk, 2002; Cloitre, 2020). Complex PTSD has been included in the ICD-11 classification (WHO, 2019); to the PTSD criteria, three additional clusters of the Disturbances of Self Organisation (DSO) construct have been added. The dimensions that constitute DSO show significant overlap with the elements that characterize personality disorders, often comorbid with cPTSD.

Most studies focus only on PTSD symptoms but not DSO symptoms; we believe it is important to implement treatment models that also address the DSO dimension.

In this case study we show the application of Metacognitive Interpersonal Therapy (MIT; Dimaggio et al., 2015) adapted for the treatment of cPTSD. MIT is an evidence-based manualised treatment developed for the treatment of personality disorders (Dimaggio et al., 2020; Dimaggio et al., 2015). We hypothesize that Metacognitive Interpersonal Therapy could be useful for treatment of cPTSD, starting precisely from underlying personality aspects; it is a treatment aimed at addressing core symptoms and the DSO construct, in line with the three-phase model. In this article, we will describe the clinical case of Gigi, a 25-year-old man who presented with cPTSD and aspects suggestive of Obsessive-Compulsive Personality Disorder.

Starting from brief clinical vignettes referring to some peculiar passages of the therapeutic process, we will show the procedures and interventions that characterize this intervention model. At the end of treatment, the patient showed a reduction in anxiety symptoms as well as repetitive thinking; he did not report any dissociative symptoms or disturbing intrusive thoughts. With regard to the elements of the DSO construct, Gigi showed a progressive reduction in episodes of dysregulation and an improvement in interpersonal functioning and his self-image.