Paranoia and the cascade of psychotic like experiences

Background: Several researchers have explored the role of paranoia in the context of psychotic disorder and psychotic like experiences (PLEs). Moreover, several cognitive models have attempted to elucidate how and why paranoia... [ view full abstract ]

Background: Several researchers have explored the role of paranoia in the context of psychotic disorder and psychotic like experiences (PLEs). Moreover, several cognitive models have attempted to elucidate how and why paranoia emerges and what impact it has on an individual’s psychology. Promoting a cascade hypothesis, the current study attempted to demonstrate that paranoia (i) plays a central role in the continuum of psychotic experiences and (ii) may precede other PLEs and begin a cascade of delusional beliefs.                 

Method:  Data (N=5850) from the Survey of Psychiatric Morbidity in Great Britain (2000) and the National Epidemiologic Survey on Alcohol and Related Conditions (N=34,653) were used.  In each dataset, items measuring schizotypal personality disorder were modelled using IRT analysis.  Analyses were conducted in two linked stages:  In the first stage, one-parameter models measuring item difficulty were estimated.  In the second stage, two-parameter models which also measured item discrimination were estimated. 

Results: The two parameter models returned better model fit.  Paranoia items had strong discrimination scores in all models. This suggested that paranoia experiences were strong indicators of the underlying psychosis construct.  Paranoia items also had some of the lowest difficulty scores. This suggested that paranoia experiences were representative of some of the most likely PLEs to occur and that paranoid ideation is likely to precede other psychotic experiences such as odd beliefs or perceptual distortions.

Conclusion:  Within the context of a cascade hypothesis, these findings are congruent with the prediction that paranoia may emerge before other psychotic symptoms and that paranoia may be a central feature of the overall psychosis construct.