Depression, use of medical services and cost-offset effects.

This review considers evidence that depression is associated with increased use of general medical services and that more intensive treatment of depression might be expected to reduce medical expenditures. Cross-sectional studies strongly support an association between depression and medical utilization, but cannot establish a causal relationship. Available longitudinal studies lack the sample size and duration of follow-up necessary to examine how changes in depression influence utilization. Some quasi-experimental and experimental studies support a "cost-offset" effect due to mental health treatment, but no experimental data directly address the specific impact of depression treatment on medical utilization. The available data identify the potential for large cost savings through improved treatment of depression but do not clearly establish that such savings can be realized. Definitive proof of a cost-offset due to depression treatment will require a new generation of experimental studies adapted to assess economic outcomes.