International and indigenous diagnoses of mental disorder among Vietnamese living in Vietnam and Australia

Background Whether the prevalence rates of common mental disorders can be compared across countries depends on the cultural validity of the diagnostic measures used. Aims To investigate the prevalence of Western and indigenously defined mental disorders among Vietnamese living in Vietnam and in Australia, comparing the data with an Australian-born sample. Method Comparative analysis of three multistage population surveys, including samples drawn from a community living in the Mekong Delta region of Vietnam (n=3039), Vietnamese immigrants residing in New South Wales, Australia (n=1161), and an Australian-born population (n=7961). Western-defined mental disorders were assessed by the Composite International Diagnostic Interview (CIDI) 2.0 and included DSM-IV anxiety, mood and substance use disorders as well as the ICD-10 category of neurasthenia. The Vietnamese surveys also applied the indigenously based Phan Vietnamese Psychiatric Scale (PVPS). Functional impairment and service use were assessed. Results The prevalence of CIDI mental disorders for Mekong Delta Vietnamese was 1.8% compared with 6.1% for Australian Vietnamese and 16.7% for Australians. Inclusion of PVPS mental disorders increased the prevalence rates to 8.8% for Mekong Delta Vietnamese and 11.7% for Australian Vietnamese. Concordance was moderate to good between the CIDI and the PVPS for Australian Vietnamese (area under the curve (AUC)=0.77) but low for Mekong Vietnamese (AUC=0.59). PVPS- and CIDI-defined mental disorders were associated with similar levels of functional impairment. Conclusions Cultural factors in the expression of mental distress may influence the prevalence rates of mental disorders reported across countries. The findings have implications for assessing mental health needs at an international level.