Background: Current cognitive models of positive symptoms of psychosis suggest a mechanism of defective self-monitoring that may be relevant for (i) expression of psychosis at the clinical and subclinical level and (ii) transmission of risk for psychosis.
Method: The study included 41 patients with psychosis, 39 non-psychotic first-degree relatives, 39 subjects from the general population with a high level of positive psychotic experiences, and 52 healthy controls with an average level of positive psychotic experiences. All subjects performed a speech attribution task in which single adjectives with a complimentary or derogatory meaning were presented to them on a computer screen; subjects had to read aloud and determine the source (self/other/uncertain) of the words they heard. In some of the trials, participants' speech was distorted, in others they heard someone else's voice (alien feedback condition) that could also be distorted.
Results: No large or significant differences in errors in the speech attribution task were found between the four groups in any of the conditions.
Conclusions: Contrary to previous work using this paradigm, this study found no evidence that either expression of psychosis or risk for psychosis was associated with impairment in self-monitoring.