Background. Reduction of health inequalities is a major policy goal in the UK. While there is general recognition of the disadvantaged position of people with mental health problems, the extent of inequality, particularly the association with socio-economic characteristics, has not been widely studied. We aimed to measure income-related inequality in the distribution of psychiatric disorders and to compare with inequality in other health domains.

Method. The concentration index (CI) approach was used to examine income-related inequality in mental health using data from the Psychiatric Morbidity Survey 2000 for Britain.

Results. There is marked inequality unfavourable to lower income groups with respect to mental health disorders. The extent of inequality increases with the severity of problems, with the greatest inequality observed for psychosis. Income-related inequality for psychiatric disorders is higher than for general health in the UK. Standardized CIs suggest that these inequalities are not due to the demographic composition of the income quintiles.

Conclusions. Income-related inequalities exist in mental health in Britain. As much of the observed inequality is probably due to factors associated with income and not due to the demographic composition of the income quintiles, it may be that these inequalities are potentially ‘avoidable’.