The Internal Revenue Service and Centers for Medicare & Medicaid Services propose amendments to regulations implementing the Paul Wellstone and Pete Domenici Mental Health Parity and Addiction Equity Act of 2008 (MHPAEA) and propose new regulations implementing the nonquantitative treatment limitation (NQTL) comparative analyses requirements under MHPAEA, as amended by the Consolidated Appropriations Act, 2021 (CAA, 2021). Specifically, these proposed rules would amend the existing NQTL standard to prevent plans and issuers from using NQTLs to place greater limits on access to mental health and substance use disorder benefits as compared to medical/surgical benefits. As part of these changes, these proposed rules would require plans and issuers to collect and evaluate relevant data in a manner reasonably designed to assess the impact of NQTLs on access to mental health and substance use disorder benefits and medical/surgical benefits, and would set forth a special rule with regard to network composition. The Departments also solicit comments on whether there are ways to improve the coverage of mental health and substance use disorder benefits through other provisions of Federal law. Comment period extended to October 17, 2023.