Delusion-like experiences in older people with anxiety disorders

Little is known about the occurrence of psychotic or quasi-psychotic experiences in older people with anxiety disorders.

We used a cross-sectional national probability sample of community-residing individuals to investigate the prevalence and correlates of delusion-like experiences in older people with DSM-IV anxiety disorders. The 2007 Australian National Survey of Mental Health and Well-being (NSMHWB) included 1,905 persons between the ages of 65 and 85 years. Anxiety disorder diagnoses were established using the Composite International Diagnostic Interview (CIDI v3). Participants were asked about three types of delusion-like experiences: thought control or interference, special meaning, and special powers. We used multivariate logistic regression to examine the relationship between a 12-month history of any anxiety disorder and the presence of these delusion-like experiences, adjusting for several potential confounders.

Eighty-two of 1,905 (4.3%) older people met criteria for an anxiety disorder over the previous 12 months. Of these, six reported delusion-like experiences, whereas the prevalence of these experiences among older people without anxiety disorder was 26/1,822 (7.3% vs. 1.4%; χ(2) = 16.5; p = 0.000). In a logistic regression model, male gender (OR 0.38; p = 0.019), separated marital status (OR 4.86; p = 0.017), and the presence of anxiety disorder (OR 5.33; p = 0.001) were independently associated with delusion-like experiences, whereas MMSE (Mini-Mental State Examination) score, general medical conditions and affective disorder were not.

In this cross-sectional study, self-reported delusion-like experiences occurred at increased prevalence among community-residing older persons with anxiety disorder. More work is needed to clarify the nature and significance of these findings.