Structure of beliefs about the helpfulness of interventions for depression and schizophrenia: Results from a national survey of the Australian public

Background: The public tends to have different views from professionals about the treatment of mental disorders. It has been proposed that these differences do not simply reflect a lack of knowledge about treatments, but also the operation of pre-existing general belief systems about health interventions. The present study uses factor analysis to examine the structure of public beliefs about interventions for depression and schizophrenia, using case vignettes that vary in severity or stage of illness. Methods: In a national survey of 3,998 Australian adults, respondents were presented with one of four vignettes: depression, depression with suicidal thoughts, early schizophrenia and chronic schizophrenia. Respondents were asked about the likely helpfulness or harmfulness of a wide range of interventions for the person in the vignette. Methods suitable for ordinal data were used to explore a range of factor analytic solutions. Once identified, the location of participants on each factor was estimated by calculating a mean score for items loading highly on that factor. These scale means were compared between subgroups of participants. Results: Four factors were found. Three of these - Lifestyle, Psychological and Medical - corresponded to previously found factors. An additional factor named Information-seeking was defined by items that had not been included in earlier research. These items concerned obtaining information or advice from a variety of sources including the internet, books and health educators. Differences on the factors were a function of socio-demographic factors and ability to identify the condition portrayed in the vignette. However, the magnitude of these differences was small. Differences between factors were more pronounced, with mean ratings on the Medical factor falling between harmful and neutral, while mean ratings on other factors lay between neutral and helpful. Conclusion: The public tends to favour psychological and lifestyle interventions over medical ones. These beliefs do not reflect specific knowledge about the effectiveness of particular treatments, but rather general commitments to broad classes of treatment that are applied irrespective of the type of mental disorder. Educational campaigns to improve public knowledge about treatments will need to take account of these pre-existing belief systems.