Jumping to delusions? Paranoia, probabilistic reasoning, and need for closure

INTRODUCTION: The present study was designed to replicate and extend the findings of Bentall and Swarbrick (2003). It was hypothesised that patients with a history of persecutory delusions would display higher need for closure and a more extreme jumping to conclusions bias than healthy control participants. METHODS: Twenty-two patients with a history of persecutory delusions and nineteen healthy control participants were administered a probabilistic reasoning task, along with self-report measures of depression and need for closure. RESULTS: The clinical group scored higher on need for closure than the controls, but showed no greater tendency to jump to conclusions. No relationship was found between need for closure and a jumping to conclusions bias. CONCLUSIONS: The results confirm an association between persecutory delusions and need for closure, yet suggest that persecutory delusions in an outpatient sample can be seen in the absence of a jumping to conclusions bias.