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A Measure of State Persecutory Ideation for Experimental Studies

Freeman, Daniel PhD*; Pugh, Katherine BSc*; Green, Catherine PhD*; Valmaggia, Lucia PhD; Dunn, Graham PhD; Garety, Philippa PhD*

The Journal of Nervous and Mental Disease: September 2007 - Volume 195 - Issue 9 - p 781-784
doi: 10.1097/NMD.0b013e318145a0a9
Brief Report

Experimental research is increasingly important in developing the understanding of paranoid thinking. An assessment measure of persecutory ideation is necessary for such work. We report the reliability and validity of the first state measure of paranoia: The State Social Paranoia Scale. The items in the measure conform to a recent definition in which persecutory thinking has the 2 elements of feared harm and perpetrator intent. The measure was tested with 164 nonclinical participants and 21 individuals at high risk of psychosis with attenuated positive symptoms. The participants experienced a social situation presented in virtual reality and completed the new measure. The State Social Paranoia Scale was found to have excellent internal reliability, adequate test-retest reliability, clear convergent validity as assessed by both independent interviewer ratings and self-report measures, and showed divergent validity with measures of positive and neutral thinking. The measure of paranoia in a recent social situation has good psychometric properties.

Departments of *Psychology, †Psychological Medicine, Institute of Psychiatry, King's College London, Denmark Hill, London, UK; and ‡Biostatistics Group, School of Medicine, University of Manchester, Manchester, UK.

Supported by Wellcome Trust Fellowship (to D.F).

Send reprint requests to Daniel Freeman, PhD, Department of Psychology, PO Box 77, Institute of Psychiatry, King's College London, Denmark Hill, London, SE5 8AF, UK. E-mail:

© 2007 Lippincott Williams & Wilkins, Inc.