Rural-urban comparisons of item responses in a measure of depression

A number of stereotypes about rural life, such as the pastoral and tranquil—yet stoic hardworking view, have guided researchers to suggest that there may be differences in the incidence of mental illness along the rural-urban continuum. This research investigates the possibility that some of the differential findings related to depression, in which urban prevalence of Major Depression has been found to be higher than rural rates of depression, may be partially accounted for by differential endorsement of survey items used to identify those who are depressed. The Diagnostic Interview Schedule (DIS) was administered to 1,900 respondents who were either part of a panel study or randomly selected to participate in a study about rural helpseeking for depression and alcohol related disorders. Two methodologies were used to examine differential item function (DIF) including a two-parameter logistic IRT model (2-PL) and a Structural Equation Model referred to as MIMIC (Multiple Indicators-Multiple Cause). The 2PL identified a majority of the items as functioning differentially. The MIMIC model allowed for statistical control of demographic and cultural variables which have previously been used to explain differences in the incidence of depression along the rural-urban continuum. After controlling for the level of depression, demographic characteristics, and several cultural variables (such as self-reliance, fatalism, etc.), three items were found to function differentially along the rural urban continuum. These include ‘sadness’, ‘loss of appetite’ and, ‘loss of interest in sex’. Rural residents were more likely to endorse the sadness item and less likely to endorse the loss of appetite and loss of interest in sex items, after depression was statistically accounted for. This finding has implications for those who conduct rural mental health research as well as for rural health and mental health practitioners and policy makers. Specifically, researchers may need to address concerns about how survey items translate across cultural and structural domains. Health care practitioners should be cautioned that the portrait of depression may vary along the rural-urban continuum and rural residents may report different symptoms of depression than urban residents. Policy makers will need to evaluate incidence and prevalence of mental illness and the needs of the rural community in the light of surveys which may underestimate rural rates of mental illness