Background: While an extensive literature documents the influence of depression on general medical services utilization, estimates of the economic burden of depression have focused on the direct costs of depression treatment. Higher use of general medical services may contribute significantly to the true cost of depressive illness.
Methods: Computerized record systems of a large staff-model health maintenance organization (HMO) were used to identify consecutive primary care patients with visit diagnoses of depression (n = 6257) and a comparison sample of primary care patients with no depression diagnosis (n = 6257). The HMO accounting records were used to compare components of health care costs.
Results: Patients diagnosed as depressed had higher annual health care costs ($4246 vs $2371, P < .001) and higher costs for every category of care (eg, primary care, medical specialty, medical inpatient, pharmacy, laboratory). Similar cost differences were observed for each of the subgroups examined (patients treated with antidepressants, those not treated with antidepressants, and those diagnosed at routine physical examination visits). Pharmacy records indicated greater chronic medical illness in the diagnosed depression group, but large cost differences remained after adjustment ($3971 vs $2644). Twofold cost differences persisted for at least 12 months after initiation of treatment.
Conclusions: Diagnosis of depression is associated with a generalized increase in use of health services that is only partially explained by comorbid medical conditions. In the primary care sector, this greater medical utilization exceeds direct treatment costs for depression. The persistence of utilization differences suggests that recognition and initiation of treatment alone are not adequate to reduce utilization differences.