Psychometric properties of the Peters et al Delusions Inventory 21 in college students.

Delusions show high prevalence in the general population and can be considered a risk marker for psychotic disorders. Although the assessment of these experiences has made considerable progress in recent years, there is still room for improvement in the measurement quality of the self-reports available for such assessment. The goal of the present work was to analyze the measurement quality of the Peters et al Delusions Inventory 21 (PDI-21) in Spanish college students. The final sample was made up of 660 participants (29.5% men) with a mean age of 20.3 years (SD, 2.6 years). The results revealed that a high percentage of the sample reported some symptom of paranoia. Analysis of the internal structure of the PDI-21 by means of exploratory factor analysis based on the tetrachoric correlation matrix yielded an essentially unidimensional solution. Cronbach α for the total score was .91. Scores on the PDI-21 correlated in a statistically significant fashion with trait and state anxiety and negative affect. These results provide new evidence of the validity of the PDI-21 and endorse its use as a measurement instrument for assessing the extended psychosis phenotype in nonclinical population.