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.