Impact of Serious Mental Illness on Medicaid and Other Public Healthcare Costs in Texas.

Medicaid-enrolled adults with serious mental illness may be dually-enrolled in Medicare, and may receive health care services from other state and local programs. To understand cross-program costs of care, we linked 2012 payment data across Medicaid, Medicare, state, and local programs. Average costs were calculated according to presence/absence of SMI, Medicare coverage, SSI coverage, medical comorbidities, and other characteristics. Costs for Medicaid adults with SMI were 57.4% greater than adults without SMI, but only 23.6% of costs were SMI-related. Greater costs were associated with Medicaid-Medicare dual-eligibility, multiple SMI diagnoses, and medical comorbidities. The results support cross-program efforts such as joint Medicaid-Medicare managed care and integrated care.