Persecutory delusions, a key symptom of schizophrenia, may be associated with the experience of early childhood trauma as well as with cannabis dependence. Little research has, however, addressed these associations in people with schizophrenia on the African continent. We examined if persecutory delusions were significantly associated with childhood trauma in people with schizophrenia from South Africa, and we investigated whether cannabis dependence mediates or moderates this association.

Seven hundred and twenty-eight people with schizophrenia completed several scales including the childhood trauma questionnaire (CTQ) which captures several domains of childhood trauma. Logistic regression and structural equation modelling methods were employed to examine the relationship between persecutory delusions and specific experiences of childhood trauma, and to determine if cannabis dependence is mediating or moderating this relationship.

Preliminary results suggest that of the various childhood traumas, the strongest predictor of the presence of persecutory delusions was emotional abuse [OR: 1.02 (0.94–1.08)]. There was no evidence of mediation by cannabis dependence. However, all experiences of childhood trauma, measured by the CTQ (with the exception of physical neglect) interacted with cannabis dependence to increase the risk of the onset of persecutory delusions (P < 0.001).

These results are consistent with previous data in demonstrating that both childhood trauma and cannabis dependence are associated with persecutory delusions in schizophrenia. These findings suggest that it is important to examine the role of early childhood trauma as well as substance use in predicting the onset of psychosis to inform treatment strategies.

The author has not supplied his/her declaration of competing interest.