BACKGROUND The costs and the effectiveness of mental health services need to be evaluated if provision is to be efficient. Service use and costs are described for two geographical areas in south London.
METHOD Service use was measured comprehensively for clients in both sectors for two six-month time periods using the Client Service Receipt Interview. This information was combined with unit costs to calculate service costs. The 'hidden' costs of informal care and unsupported accommodation were also calculated.
RESULTS At baseline significantly more intensive sector clients had in-patient stays but by the follow-up this difference had disappeared. There was significantly more use of supported accommodation in the intensive sector during both time periods. Baseline and follow-up total service costs were significantly higher for the intensive sector. Costs were spread disproportionately and a small number of services accounted for a large proportion of cost.
CONCLUSIONS While the cost at Time 2 was significantly greater in the intensive sector, this was largely due to the high use of supported accommodation. There was some convergence in cost between the sectors over time.