Impairment of self-monitoring: part of the endophenotypic risk for psychosis.

Background: A disorder of self-monitoring may underlie the positive symptoms of psychosis. The cognitive mechanisms associated with these symptoms may also be detectable in individuals at risk of psychosis.

Aims: To investigate (a) whether patients with psychosis show impaired self-monitoring, (b) to what degree this is associated with positive symptoms, and (c) whether this is associated with liability to psychotic symptoms.

Method: The sample included: individuals with a lifetime history of non-affective psychosis (n=37), a genetically defined risk group (n=41), a psychometrically defined risk group (n=40), and control group (n=49). All participants carried out an action-recognition task.

Results: Number of action-recognition errors was associated with psychosis risk (OR linear trend over 3 levels:1.12, 95% CI1.04-1.20) and differential error rate was associated with the degree of delusional ideation in a dose-response fashion (OR linear trend over 3 levels:1.13, 95% CI1.00-1.26).

Conclusions: Alterations in self-monitoring are associated with psychosis with evidence of specificity for delusional ideation. In the risk state, this is expressed more as failure to recognise self-generated actions, whereas in illness failure to recognise alien sources come to the fore.