Association between trauma exposure and delusional experiences in a large community-based sample

Background: Surveys have found that otherwise well individuals report delusional experiences. Previous studies have shown an association between psychotic symptoms and exposure to trauma.

Aims: To explore the association between trauma and delusional experiences in a community sample.

Method: Respondents (n=10 641) were assessed for delusional experiences, exposure to various types of traumatic experiences and the presence of post-traumatic stress disorder (PTSD). The endorsement of delusional items was examined in people exposed to traumatic events who did or did not have PTSD.

Results: Exposure to any traumatic event but without the development of PTSD was associated with increased endorsement of delusional experiences (relative risk 2.68, 95% CI 2.18-3.30) and there was a significant dose-response relationship between the number of types of traumatic events and endorsement of such experiences (chi(2) =26.74, d.f.=2, P<0.001). A diagnosis of PTSD further increased endorsement of delusional experiences (RR=9.24, 95% CI 6.95-12.27). The association between PTSD and delusional experiences remained significant after adjusting for factors associated with psychotic symptoms.

Conclusions: Further investigation into the pathways between trauma, delusions and psychosis may provide insights into shared aetiological mechanisms underpinning these conditions.