Abstract
One of the most used self-administered instruments to assess persecutory delusions is the Persecutory Ideation Questionnaire (PIQ). Individual differences in PIQ scores are important because they predict the severity of symptoms associated with psychosis-related disorders. The current research demonstrates that PIQ is associated with two new outcomes: Satisfaction with life (Studies 1 and 2) and therapy length needed for hospital discharge (Study 2). Most relevant, we introduce meta-cognitive confidence in one's scale responses as a construct capable of improving the predictive validity of the PIQ. Across two studies, participants from the general population (Study 1) and from a clinical sample (Study 2) completed the PIQ and then reported the confidence in their responses. As expected, the PIQ was associated with satisfaction with life in both cases and duration of therapy required to receive hospital discharge for the clinical sample. Most importantly, confidence further moderated the extent to which the PIQ scores were linked with both outcomes, with greater consistency between the PIQ and the dependent measures obtained for those with higher confidence. Therefore, asking a single item about the confidence associated with responses to the PIQ enhances the association of PIQ scores and relevant consequences across domains.