Investigating the cognitive mechanisms underlying paranoia : a systematic review and experimental investigation

• Main Author: Collins, Charlotte
• Other Authors: Rowse, Georgina ; Emerson, Lisa-Marie
• Published: University of Sheffield 2015
• Subjects: 150
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.647026

Paranoia (often manifest as persecutory delusions) is a common symptom of psychosis, but is also seen in the general population. A continuum model of psychosis suggests that investigation into the underlying mechanisms and processes involved in paranoia in both clinical and non-clinical populations will be helpful in informing our understanding and future treatment of this symptom. Firstly, a systematic review was conducted of the literature to investigate the role of worry in paranoia in clinical samples. High levels of worry were found throughout the literature, often comparable to those found in samples with generalised anxiety disorder. There was some evidence to suggest that there are similar underlying processes in anxiety and paranoia. There may be a role of metacognitive beliefs about worry in particular. The effectiveness of some preliminary treatments for worry in paranoia is also discussed, along with the methodological limitations of the literature. Secondly, an experiment was conducted, investigating the relationship between paranoia, intrusive thoughts, executive functioning, and mood in a non-clinical sample. Results found that paranoid intrusive thoughts may be a type of intrusive thought worthy of investigation in its own right. An increase in paranoia score was also found to predict perceived difficulty dismissing a paranoid intrusive thought, over and above the effect of mood, age and gender. Participants with increased selective attention to threat words also found paranoid intrusive thoughts harder to dismiss. There was found to be no relationship between other measures of executive functioning and dismissibility of paranoid intrusive thoughts. Clinical implications are discussed.