Investigating Factors that Bias the Reporting of Depression Symptomatology Among Older Australian Adults.

ABSTRACT

OBJECTIVE: To investigate factors that may bias the reporting of major depression symptoms among older adults, specifically the presence of physical conditions, bereavement, episode onset, and episode length. METHODS: A secondary data analysis of a nationally representative cross-sectional survey of community-dwelling older Australian adults aged 50-85 years who completed the depression module in the 2007 Australian National Survey of Mental Health and Wellbeing (N=629) was conducted. Depression symptomatology was assessed according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria using the World Mental Health Composite International Diagnostic Interview. RESULTS: Multiple indicators multiple causes modeling indicated a unidimensional factor structure of depression. Two depressive symptoms displayed measurement noninvariance (i.e., nonequivalency) worthlessness/guilt and suicidality/thoughts of death. Specifically, older adults who were bereaved were significantly less likely to report worthlessness/guilt (OR 0.29; 95% CI 0.16-0.50) and more likely to report suicidality/thoughts of death (OR 4.67; 95% CI 2.84-7.68), compared with older adults who were not bereaved. Examination of latent mean differences revealed that older adults with physical conditions displayed significantly greater depression severity compared with older adults without physical conditions. CONCLUSION: The presence of physical conditions and episode onset and length do not appear to differentially influence reporting of depression symptoms among older Australian adults, suggesting these factors do not bias prevalence estimates of depression. Reporting of worthlessness/guilt and suicidality/thoughts of death may be biased toward older adults who are bereaved; however, these did not influence overall depression severity.