; and (iii) maintain an affiliation agreement with a provider that can prescribe or otherwise dispense all other forms of drugs approved by the Food and Drug Administration for the treatment of substance use disorder. (3) GAO study Not later than 1 year after the date of enactment of this title, the Comptroller General of the United States shall submit to Congress a comprehensive report describing any relationship between substance use rates, pain management practices of the Indian Health Service, and patient request denials through the purchased/referred care program of the Indian Health Service. (d) Ensuring a full continuum of services (1) In general Not later than 6 months after the date of the enactment of this title, the Administrator of the Centers for Medicare & Medicaid Services shall issue a State Medicaid Director letter and tribal leader letter explaining how States and tribes can ensure access to a continuum of services for adults with substance use disorders who are receiving medical assistance under title XIX of the Social Security Act. Such letter shall describe how States can cover the continuum of community-based, residential, and inpatient substance use disorder services and care coordination between different levels of care as medical assistance, as defined in section 1905(a) of such Act, including through section 1915 of such Act and through demonstration projects under section 1115 of such Act. (2) MACPAC Analysis Not later than 1 year after the date of the enactment of this title, the Medicaid and CHIP Payment and Access Commission shall conduct an analysis, and make publicly available a report containing the results of such analysis, of States’ coverage of substance use services for Medicaid beneficiaries. Such report shall include examples of promising strategies States use to cover a continuum of community-based substance use services. (3) Annual assessment Beginning with respect to fiscal year 2022, the Secretary shall make a determination with respect to each State on whether the State