Two predictions about paranoid ideation: deluded, depressed and normal participants' subjective frequency and consensus judgments for positive, neutral and negative events.

Abstract

Two groups of patients suffering from persecutory delusions, one consisting of patients also suffering from depression and a non-depressed group, together with clinically depressed and normal controls matched with the deluded patients for age and intelligence, were asked to rate the frequency with which selected positive, negative and neutral events had happened to themselves and to an average other person in the past, and the frequency with which these events were likely to happen to themselves and to an average other person in the future. Results were similar for both past and expected future events. Non-depressed-deluded, depressed-deluded and depressed patients rated negative events as occurring relatively more frequently in comparison to the normal controls. Depressed participants rated positive events as occurring more frequently to others, whereas the normal participants rated negative events as occurring more often to others. Correlational analyses indicated that depression scores were associated with low estimates of the frequency with which positive events happen to self and high estimates of the frequency with which negative events happen to self. Magical ideation scores, an index of psychosis, were associated with high estimates of the frequency of negative events for both self and others. These findings are interpreted in the context of previous evidence on cognitive biases in deluded patients.