Document the healthcare resource utilization and costs by severity for persons in the workforce with major depressive disorder (MDD).

Using the National Comorbidity Survey-Replication data, workforce respondents (n=4,465) were categorized by clinical severity (not clinically depressed, mild, moderate, severe) using standard scales (CIDI/QIDS-SR). Outcomes measured over 12 months included prevalence of medical services/antidepressant use, average number of visits and days on antidepressants, prevalence of treatment adequacy, and medical/drug costs. Costs represent insurer payments to providers and were estimated by weighting utilization measures by unit costs obtained for similar services used by depressed patients in a U.S. employer claims database for the corresponding period (2000-2001). Outcomes were compared across depression severity groups using multivariate analyses adjusting for demographics.

Among the 539 depressed workforce respondents, 13.8% were mildly, 38.5% moderately and 47.7% severely depressed. A significant association existed between severity and prevalence of mental health services usage (19.1%, 27.2%, and 40.3% respectively, p< 0.01) and average number of mental health practitioner visits. The use of antidepressants increased with depression severity (21.1%, 27.3%, and 39.5% respectively, p< 0.01). Similarly, the adequacy of mental health services increased with depression severity (6.2%, 11.8%, and 21.3% respectively, p< 0.05). Average 12-month costs per MDD patient were substantially higher for severe vs. mild (mental health services: $697 vs. $388; general medical services: $138 vs. $53; anti-depressant usage $256 vs. $88).

Among workforce respondents, there was a significant association between depression severity and treatment usage and costs, and between treatment adequacy and severity.