Inpatient charges and mental illness: Findings from the Nationwide Inpatient Sample 1999–2007

Inpatient costs related to mental illness are substantial, though declining as a percentage of overall mental health treatment costs. The public sector has become increasingly involved in funding and providing mental health services. Nationwide Inpatient Sample data for the years 1999–2007 were used to: 1) examine Medicare, Medicaid, and private insurance charges related to mental illness hospitalizations, including trends over time; and 2) examine trends in mental comorbidity with physical illness and its effect on charges. There were an estimated 12.4 million mental illness discharges during the 9-year period, with Medicare being the primary payer for 4.3 million discharges, Medicaid for 3.3 million, private insurance for 3.2 million, and 1.6 million for all other payers. Mean inflation-adjusted charges per hospitalization were US$17,528, US$15,651, US$10,539, and US$11,663, respectively. Charges to public sources increased for schizophrenia and dementia-related discharges, with little private/public change noted for mood disorders. Comorbid mood disorders increased dramatically from 1.5 million discharges in 1999 to 3.4 million discharges in 2007. Comorbid illness was noted in 14.0% of the 342 million inpatient discharges during the study period and was associated with increased charges for some medical conditions and decreased charges for other medical conditions.