Background: People with a low material living standard experience more psychological distress than those with a high living standard, but previous studies suggest the size of this difference is modest.

Aim: To measure the association between living standard and psychological distress using a multidimensional measure of living standard, the Economic Living Standard Index (ELSI).

Methods: Adults aged 25–64 years (n = 8,465) were selected from a New Zealand community survey. Logistic regression models were used to compare household income and ELSI scores as risk factors for high psychological distress, defined as a K10 score of 12 or over.

Results: In the population, the prevalence of high psychological distress was 5.8%. The prevalence of high distress increased steeply with decreasing living standard. In the most deprived decile according to ELSI score, 24.3% had high distress, compared to 0.8% in the least deprived decile. For household income, high distress was present in 15.9% of people in the lowest decile and 2.2% of the highest decile. In fully adjusted models, ELSI score remained significantly associated with high distress but household income was not.

Conclusion: The mental health disparity between those at opposite ends of the social spectrum is very large. Comprehensive measures such as the ELSI give a more accurate estimate of this disparity than household income.