Childhood trauma increases the risk for psychosis. However, mechanisms underlying this relationship remain unclear. In the present study, we aimed to investigate whether negative cognitive self-schemas or basic self-disturbance mediate the association between childhood trauma subtypes (abuse and neglect) and psychotic experiences in patients with psychotic disorders, unaffected siblings, and healthy controls.

This study was performed in a subsample of 110 patients, 120 siblings, and 48 healthy controls within the Genetic Risk and Outcome of Psychosis (GROUP) study. Parallel mediation models were used while correcting for age and sex. Abuse and neglect were measured with the childhood trauma questionnaire (CTQ), psychotic experiences with the Community Assessment of Psychic Experiences (CAPE), self-disturbance phenomena with the Self-Experience Lifetime Frequency Scale (SELF), and negative self-schemas with the Brief Core Schemas Scale (BCSS).

In patients, negative self-schemas fully mediated the association between abuse and psychotic experiences, whereas self-disturbance partly mediated the effect of neglect on psychotic experiences. In siblings, both negative self-schemas and self-disturbance fully mediated the association between abuse/neglect and psychotic experiences. In controls, only negative self-schemas mediated the association between abuse and neglect and psychotic experiences.

Our findings suggest that negative self-schemas and self-disturbance phenomena are relevant factors in explaining the association between childhood trauma and psychotic experiences across illness liability groups. Further research is needed to explore the causal pathways between trauma, negative self-schemas, self-disturbance phenomena, and psychotic experiences.