Background: To assess the prevalence of delusional ideas in primary-care patients.
Method: A survey was carried out with the Aquitaine Sentinel Network of general practitioners (GPs). Consecutive practice attenders were invited to complete the Peters et al. Delusional Inventory (PDI-21) self-report questionnaire, designed to measure delusional ideation in the normal population. GPs, blind to the questionnaire results, provided information on patients' psychiatric history.
Results: Of the 1053 attenders included in the survey, 348 (35%) had a lifetime history of psychiatric disorder, of whom 20 (2%) had a history of broadly defined psychotic disorder. The self-report questionnaire was completed by 790 patients. The range of individual PDI-21 item endorsement in subjects with no psychiatric history varied between 5 and 70%, suggesting that delusional ideation is a dimensional phenomenon lying on a continuum with normality. The main discriminative items between psychotic and non-psychotic patients were those exploring persecutory (OR = 15.2, 95% CI 4.3-53.7), mystic (OR = 6.4, 95% CI 1.9-22.4) and guilt (OR = 5.8, 95% CI 1.5-23.2) ideas.
Conclusions: This survey demonstrates that questions that explore delusions and hallucinations are well-accepted by most primary-care patients. More research is needed on psychotic disorders in primary-care settings to improving early identification of these disorders.