Abstract
Background: The aim of this study was to adapt and obtain validity evidence of the Spanish Green Paranoid Thought Scales (S-GPTS). Method: 191 Spanish people responded to S-GPTS, Peters Delusions Inventory (PDI), and measures of psychopathology. Results: Principal Component Analyses on the polychoric correlation matrix identified two factors accounting for 71.0% of the cumulative variance. Cronbach alphas for S-GPTS total and its subscales were above .90 in clinical and non-clinical group. The value of the area under the receiver operating characteristic curve was higher for the S-GPTS (.898), than for the PDI (.859). The best S-GPTS threshold to discriminate between cases and non-cases was 92 (sensitivity, 97.35%; specificity, 65%). S-GPTS scores positively correlated with PDI and measures of anxiety and depression. Conclusion: The S-GPTS has adequate psychometric properties to provide valid measures of delusional ideation in a Spanish population.
