Would socio-economic inequalities in depression fade away with income transfers?

A number of recent studies have questioned the conventional view regarding the existence of income-related inequalities in depression and have suggested that other factors have a more marked impact, most notably those socio-environmental effects linked to professional status and educational attainment. This paper seeks to measure and decompose the degree of socio-economic inequality in the factors underlying reported depression by drawing on data from Spain (Spanish National Health Survey, 2003), a country in which mental care coverage is somewhat limited, but where a marked social transformation has been apparent in recent decades. Contrary to recent evidence, our findings point towards the existence of significant income-related inequalities in the prevalence of reported (diagnosed) depression. However, the results from our decomposition analysis are more mixed. While a modest proportion of overall inequalities (6–13%) is accounted for by income alone, labour status, demographics and education appear to be more relevant. However, when controlling for potential endogeneity between income and depression by using instrumental variables (IV), income is found to account for more than 50% of overall inequality in reported depression.