Preoccupation and distress are relevant dimensions in delusional beliefs

Background and Purpose: A large number of subjective experiences and beliefs with some degree of affinity with psychotic symptoms can be found in the general population. However, the appraisal of these psychotic-like experiences in terms of associated distress, raised preoccupation, and the conviction with which the experience is held can be more discriminative in distinguishing people in need for care from those who simply hold unusual or uncommon beliefs because of cultural reasons. Method: In this study, 81 patients with a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, diagnosis of schizophrenia or an affective disorder with psychotic features were compared on the Peters et al Delusions Inventory (PDI) to 210 people from the same local area, who had never received a formal diagnosis of a mental disorder. Results: Patients scored higher than controls on the PDI total score and on its distress, preoccupation, and conviction subscales. A stepwise logistic regression model showed PDI-preoccupation (odds ratio, 2.46; 95% confidence interval, 1.52-3.98) and, marginally, PDI-distress (odds ratio = 1.58; 95% confidence interval, 0.93-2.58) adding discriminative power to PDI total score in distinguishing patients from controls. Conclusions: The evaluation of the severity of delusion-like experiences and beliefs is important in discriminating patients diagnosed with psychosis from people who are not in need of care.