Scale Overview & Construct
18-item measure of paranoid thinking over the past month. Comprises an 8-item Ideas of Reference subscale and a 10-item Ideas of Persecution subscale. Higher scores indicate greater paranoia.
Purpose & Measurement Objectives
Instrument Specifications
Scientific Documentation & Psychometric Rigor
Internal Consistency & Reliability
Original validation study reported high internal consistency for both persecution and social reference subscales.
Construct & Criterion Validity
Validated across clinical (psychosis) and non-clinical population samples, supporting a continuum model of paranoid thinking.
Academic Citations
Green, C. E. L., Freeman, D., Kuipers, E., Bebbington, P., Fowler, D., Dunn, G., & Garety, P. A. (2008). Measuring ideas of persecution and social reference: the Green et al. Paranoid Thought Scales (GPTS). Psychological Medicine, 38(1), 101-111.
Academic Citation & Instrument Provenance
When referencing this instrument in research, academic theses, or clinical institutional audits, please cite the original author publication:
Governance, Boundaries & Ethical Use
Imported from the OpenScales open item-bank project. This specific digital implementation has not been independently clinically validated by PsiQ — scores are for self-reflection, research, and educational purposes only, and are not a diagnosis.
License: CC BY. Citation: Freeman, D., Loe, B. S., Kingdon, D., Startup, H., Molodynski, A., Rosebrock, L., Brown, P., Sheaves, B., Waite, F., Bird, J. C., Carr, L., & Clark, D. M. (2021). The revised Green et al., Paranoid Thoughts Scale (R-GPTS): psychometric properties, severity ranges, and clinical cut-offs. Psychological Medicine, 51(2), 244–253. https://doi.org/10.1017/S0033291719003155 This is not a diagnostic tool. If you are in crisis or having thoughts of self-harm, please contact a licensed mental health professional or a crisis helpline in your country immediately. Low/Moderate/High bands below reflect this test's own possible score range only (simple thirds) — they are NOT a clinical threshold or population norm. No such cutoff has been published for this instrument.