The Recovery Act amends Medicaid and the Children's Health Insurance Program to allow states to cover mental health and substance use disorder treatment services provided at certain mental health institutions, starting January 1, 2025. Under this new option, states can provide medical assistance to Medicaid-enrolled individuals under age 65 who have a substance use disorder while they are patients in eligible institutions, with coverage limited to the medically necessary period as determined by evidence-based clinical criteria and reviewed at least every 30 days. The federal government will cover 90 percent of the costs for the first five years a state participates in this program, compared to the standard matching rate, creating a strong financial incentive for state participation. To help states develop and implement these programs, the legislation provides up to $25 million in planning grants beginning in 2025. This bill aims to expand access to comprehensive mental health and addiction treatment services by removing current limitations that restrict Medicaid coverage for inpatient stays at mental health institutions.