Link between childhood trauma and psychotic-like experiences in non-affected siblings of schizophrenia patients: A case-control study

Aim Prior research has consistently demonstrated a relationship between childhood trauma (CT) exposure and an increased risk of developing psychotic-like experiences (PLE) and disorders. Studying the link between CT and PLE in non-clinical populations with or without genetic risk factors could help elucidate the etiopathogeny of psychotic disorders, by removing the effect of confounding variables related to psychotic-spectrum illnesses. Method A total of 60 non-affected siblings of patients with schizophrenia and 75 controls (aged 18-35 years) participated in a cross-sectional survey. The Positive Subscale of Community Assessment of Psychotic Experiences (CAPE) and the CT Questionnaire were used. Results We found no significant difference with regard to positive dimension of the CAPE between the two groups. Siblings have reported higher CAPE negative symptoms scores than controls (27.9 vs 24.2;P= .015), and more emotional abuse and physical neglect during childhood than controls. After controlling for demographic and psychosocial variables, sexual abuse, emotional neglect and physical neglect were positively related to positive psychotic symptoms in the control group, whereas no dimension of CT has been linked to these symptoms in the sibling group. Conclusion The link between CT and psychosis seems to be complex, not only dependent on genetic vulnerability or early environmental factors shared by siblings of patients with psychotic disorders, but also several other confounding factors, including other psychopathological symptoms. Prevention strategies for individuals at genetic risk of psychosis should pay particular attention to CT as a potential predictor of sub-clinical depression and psychosis.