This bill allows states to use Medicaid and the Children's Health Insurance Program to pay for mental health and substance use disorder treatment for incarcerated individuals, reversing a longstanding federal prohibition on such coverage. States that opt into this program would receive a 100 percent federal match for these services, meaning the federal government covers the full cost rather than the typical split with states. In exchange, states must use the additional federal funds to improve data sharing between correctional facilities and health providers, expand community-based treatment capacity, and strengthen reentry services for people being released from incarceration. The bill also requires the Government Accountability Office to report to Congress within five years on how many incarcerated people receive coverage under these programs, their access to care, the quality of services provided, and whether the coverage affects recidivism rates and successful community reintegration. The changes would take effect starting January 1, 2023, and participation is optional for states.