The Centers for Medicare and Medicaid Services will requiring states to provide mental health and substance abuse assistance as they would any other medical services for low-income adults and children.
The new rule aligns protections already required of private health plans.
The Mental Health Parity and Addiction Equity Act of 2008 generally requires that health insurance plans treat mental health and substance use disorder benefits on equal footing as medical and surgical benefits.
The final rule will benefit the over 23 million people enrolled in Medicaid managed care organizations, Medicaid alternative benefit plans, and the Children's Health Insurance Program, CMS said.
Under the final rule, plans must disclose information on mental health and substance use disorder benefits upon request, including the criteria for determinations of medical necessity.
The final rule also requires the state to disclose the reason for any denial of reimbursement or payment for services with respect to mental health and substance use disorder benefits.
Currently, states have the flexibility to provide mental health and substance abuse services through entities other than Medicaid managed care organizations, such as prepaid inpatient health plans or prepaid ambulatory health plans.
The final rule maintains this flexibility while mandating that Medicaid and CHIP enrollees have access to mental health and substance use disorder services.
CMS released the rule on Tuesday in conjunction with President Barack Obama's visit to the National Rx Drug Abuse and Heroin Summit in Atlanta this week.
CMS said the rule is the latest in efforts to increase access to and improve mental health services and care for low income individuals, especially in light of the opioid abuse epidemic, which constitute significant health risks and cost drivers in the Medicaid program.
"The Affordable Care Act provided one of the largest expansions of mental health and substance use disorder coverage in a generation," said Sylvia Burwell, secretary of Health and Human Services. "Today's rule eliminates a barrier to coverage for the millions of Americans who for too long faced a system that treated behavioral health as an unequal priority. It represents a critical step in our effort to ensure that everyone has access to the care they need.
"This rule will also increase access to evidence-based treatment to help more people get the help they need for their recovery and is critical in our comprehensive approach to addressing the serious opioid epidemic facing our nation."
In July 2015, CMS issued guidance to states to develop a full continuum of care for beneficiaries with a substance use disorder, including coverage for short-term residential treatment services not otherwise covered by Medicaid.