This study assessed the relationship between stress reactivity (trait 1) and psychosis (trait 2) across genetically related persons (cross-twin, cross-trait design) to examine whether stress reactivity is an uncontaminated and unconfounded familial marker of psychosis risk.Method
Reactivity to stress and subclinical psychotic experiences were assessed in 289 female, general population twin-pairs. Cross-trait, within-twin associations investigating the association between stress reactivity and subclinical psychotic experiences in each person, were calculated. In addition, cross-trait, cross-twin associations were calculated to assess whether stress reactivity in one twin was moderated by subclinical psychotic experiences in the co-twin.Results
Cross-trait, within-twin analyses showed significant associations between stress reactivity and subclinical psychotic experiences in each person. In addition, the cross-trait cross-twin analyses showed that stress reactivity in twin 1 was significantly moderated by subclinical experiences in the co-twin.Conclusion
The results suggest that the psychosis phenotype cosegregates with increased emotional reactivity to stress in daily life.