Background: Mental Health Research across cultural groups is often criticised for using imprecise measures of cultural group and for using outcome measures as if they have universal validity.
Aims: 1. To Investigate the effect of using different cultural group variables on the findings of a survey of prevalence of Common Mental Disorders. 2. To demonstrate that assumptions of validity for outcomes measures can affect the interpretation of data from prevalence surveys.
Methods: We recruited Punjabi and English subjects to a phase prevalence survey that included the Amritsar Depression Inventory and the General Health Questionnaire as screening instruments. The Clinical Interview Schedule was the outcome measure. This paper reports on a secondary analysis of the data. We used ethnic group, place of birth, religion, first language and language spoken at interview as possible cultural group variables and compared the prevalence estimates. We then considered the limitations of conventional methods to assess prevalence, by looking at mean scores on each of the three instruments in both cultural groups.
Results: Cultural group variables did not influence the prevalence estimates for Common Mental Disorder. Although conventional scoring methods showed no difference in prevalence across cultures, the mean scores on each instrument, when compared across cultural groups, differed for the Amritsar Depression Inventory. This instrument showed a higher mean score for the Punjabis suggesting a higher prevalence. The findings are discussed in the context of value laden 'assumptions' about validity.
Conclusions: The findings of prevalence surveys depend on assumptions of validity. The 'culture' of psychiatry is a closed system in which validation studies support its basic assumptions.