Impact of psychological trauma on the development of psychotic symptoms : relationship with psychosis proneness

Background The reported link between psychological trauma and onset of psychosis remains controversial.
Aims To examine associations between self-reported psychological trauma and psychotic symptoms as a function of prior evidence of vulnerability to psychosis (psychosis proneness).
Method At baseline, 2524 adolescents aged 14-24 years provided self-reports on psychological trauma and psychosis proneness, and at follow-up (on average 42 months later) participants were interviewed for presence of psychotic symptoms.
Results Self-reported trauma was associated with psychotic symptoms, in particular at more severe levels (adjusted OR 1.89, 95% CI 1.16-3.08) and following trauma associated with intense fear, helplessness or horror. The risk difference between those with and without self-reported trauma at baseline was 7% in the group with baseline psychosis proneness, but only 1.8% in those without (adjusted test for difference between these two effect sizes: chi(2) = 4.6, P = 0.032).
Conclusions Exposure to psychological trauma may increase the risk of psychotic symptoms in people vulnerable to psychosis.