Existing law, the Knox-Keene Health Care Service Plan Act of 1975, provides for the licensure and regulation of health care service plans by the Department of Managed Health Care and makes a willful violation of the act a crime. Existing law also provides for the regulation of health insurers by the Department of Insurance. Existing federal law, the federal Paul Wellstone and Pete Domenici Mental Health Parity and Addiction Equity Act of 2008 (MHPAEA) , requires group health plans and health insurance issuers that provide both medical and surgical benefits and mental health or substance use disorder benefits to ensure that financial requirements and treatment limitations applicable to mental health or substance use disorder benefits are no more restrictive than the predominant requirements or limitations applied to substantially all medical and surgical benefits. Existing state law requires an individual, small group, or large group health care service plan contract or health insurance policy to provide covered mental health and substance use disorder benefits in compliance with the MHPAEA and specified federal rules, regulations, and guidance. This bill would require the above-described contracts and policies to provide covered mental health and substance use disorder benefits in compliance with specified federal rules, regulations, and guidance as they existed on January 1, 2025. Because a violation of these requirements by a health care service plan would be a crime, the bill would impose a state-mandated local program. The bill would also require the departments to review provisions of the bill that conflict with or materially differ from federal regulations and collaborate with each other to issue guidance on compliance. The California Constitution requires the state to reimburse local agencies and school districts for certain costs mandated by the state. Statutory provisions establish procedures for making that reimbursement. This bill would provide that no reimbursement is required by this act for a specified reason.