Significant between-group differences in self-monitoring accuracy were found (χ2=29.3, p<0.0001), patients performing worst and unaffected siblings performing at an intermediate level compared to controls (all between-group differences p<0.05). In the combined group of healthy controls and unaffected siblings, detection accuracy was associated with positive schizotypy as measured by the Structured Interview for Schizotypy – Revised (SIS-R) (β=−0.16, s.e.=0.07, p=0.026), but not with negative schizotypy (β=−0.05, s.e.=0.12, p=0.694). In patients, psychotic symptoms were not robustly associated with detection accuracy (β=−0.01, s.e.=0.01, p=0.094), although stratified analysis revealed suggestive evidence for association in patients not currently using antipsychotic medication (β=−0.03, s.e.=0.01, p=0.052), whereas no association was found in patients on antipsychotic medication (β=−0.01, s.e.=0.01, p=0.426). A similar pattern of associations was found for negative symptoms.
Alterations in self-monitoring may be associated with familial risk and expression of psychosis. The association between psychotic symptoms and self-monitoring in patients may be affected by antipsychotic medication, which may explain previous inconsistencies in the literature.