Spouses reported substantial direct cash expenditures on behalf of the patients' illness. Since these expenditures varied to a large extent over the three points of measurement, repeated measurement designs seem to be a prerequisite for a reliable assessment of illness-associated costs. Since living together with a mentally ill partner is associated with an increased risk of developing a burden-related psychiatric illness for spouses themselves which may lead to double costs and double decreases in income, these aspects should be taken into consideration when planning changes in health policy.