Linking Childhood Trauma and Dissociation to Psychotic Symptoms in Major Depressive Disorder, Bipolar Disorders, and Schizophrenia: A Transdiagnostic Examination Using Patient and Clinician Ratings

Objective: Symptomatic overlap between dissociation and psychosis is well documented; however, the pathogenesis of these two phenomena might be distinct. Few studies have analyzed the relation of dissociative and psychotic symptoms transdiagnostically. The current study examines an emerging trauma-dissociation theoretical model that accounts for psychotic symptoms across affective disorders and schizophrenia (SCZ). Method: Psychiatric inpatients with DSM-5 major depressive disorder (MDD), bipolar disorders (BD) currently in a major depressive episode, and SCZ, and healthy controls (HC) were recruited. Potentially traumatizing events in childhood, dissociative symptoms, and psychotic symptoms were assessed. In addition to participant's self-report, dissociative and psychotic symptoms were rated by psychiatrists blind to the hypothesis. Path analysis was conducted. Results: Dissociation was commonly experienced by clinical participants, particularly for those with MDD or BD. For the SCZ group, ratings of dissociation differed between patient and clinician; specifically, patient-reported dissociation scores, but not clinician-rated scores, were higher than that of the HC group. Importantly, the links between childhood trauma, dissociation, and psychotic symptoms were not homogenous across the diagnostic groups. Dissociation mediated the relationship between childhood trauma and psychotic symptoms in the MDD and BD groups, but not the SCZ group. Conclusion: Depending on the psychiatric condition, dissociation and psychosis have different clinical implications. Childhood trauma and dissociation provide an account for psychotic symptoms in patients diagnosed with MDD and BD, but not with SCZ. Clinical Impact Statement Dissociative and psychotic symptoms often appear in an acute phase of mental disorders. Their overlap creates confusion in clinical diagnosis, though growing evidence showed that psychotic disorders such as schizophrenia may have a distinct etiology from dissociative disorders. Our findings illustrated that psychotic symptoms in patients with a predominantly depressed mood could be attributable to dissociation and childhood trauma. By contrast, this relationship between psychotic symptoms, dissociation, and childhood trauma was not evident in schizophrenia. Assessing childhood relational trauma and dissociation helps make differential diagnosis of psychotic symptoms, particularly for those in a depressive episode.