Impaired Sleep Mediates the Relationship Between Interpersonal Trauma and Subtypes of Delusional Ideation

Trauma is a robust risk-factor for delusional ideation. Yet, there is a crucial need to clarify the specificity and processes underlying this relationship. Qualitatively, interpersonal traumas (i.e., trauma caused by another person) appear to have a specific relationship with delusional ideation and furthermore seem most relevant to paranoia, a subtype of delusional ideation, given the commonality of social threat. However, these observations have not been empirically tested and the process by which interpersonal trauma contributes to delusional ideation remains poorly understood. Informed by previous literature, impaired sleep may be a critical mediator, explaining part of the relationship between interpersonal trauma and delusional ideation. Taken together, we hypothesized that interpersonal trauma, but not non-interpersonal trauma, would be positively related to subtypes of delusional ideation, especially paranoia, and that impaired sleep would mediate these relationships. In a large, transdiagnostic community sample (N=478), an exploratory factor analysis of the Peter’s Delusion Inventory identified three subtypes of delusional ideation: magical thinking, grandiosity, and paranoia. Three path models of the above relationships were tested, one for each subtype of delusional ideation. As predicted, paranoia and grandiosity were positively related to interpersonal trauma and unrelated to non-interpersonal trauma. Furthermore, these relationships were significantly mediated by impaired sleep, which appeared strongest for paranoia. In contrast, magical thinking was unrelated to traumatic experiences. These findings support a specific relationship between interpersonal trauma and delusional ideation, with impaired sleep appearing as an important process by which interpersonal trauma contributes to delusional ideation.