The experience and role of dissociation in psychosis following developmental trauma: A systematic review

Developmental trauma (DT), defined as abuse or neglect before age 18, is linked with elevated risk and poorer outcomes in psychosis. This systematic review aimed to elucidate the relationship between DT and dissociation in psychosis and discern the potential mediating role of dissociation in the link between DT and psychotic manifestations. Our study protocol was pre-registered with PROSPERO (CRD42022330026). We adopted broad criteria, including a variety of methodologies exploring dissociation post-DT in individuals exhibiting psychosis or psychotic features. Risk of bias was assessed for all included studies. Our review incorporated 40 studies, totalling 6941 participants. A significant moderate association was observed between DT and dissociation (r = 0.33 (95 %CI: 0.28-0.38)), underscored by dose-response effects. Sexual and emotional abuse demonstrated the most robust associations with dissociation. Individuals with psychosis and DT reported elevated dissociation relative to their non-traumatized counterparts. Dissociation mediated the link between DT and positive psychotic symptoms, notably hallucinations, across clinical and general populations. Five studies pinpointed dissociation's mediating role in tying DT to paranoia and delusional ideation. The review delves into clinical considerations, emphasizing screening for psychotic and dissociative symptoms in DT survivors, and outlining dissociation management strategies. Future research, employing longitudinal, qualitative, and experimental approaches, remains paramount.