Health insurance; require coverage of medically necessary treatment of mental health and substance use disorders.

HB 40 requires all health insurance policies in Mississippi providing hospital, medical, or surgical coverage (issued, amended, or renewed on or after January 1, 2026) to cover medically necessary treatment for mental health and substance use disorders. It prohibits insurers from limiting coverage for chronic conditions to only short-term or acute care and bans them from denying coverage based on the availability of public programs like Medicaid. Insurers must use current medical standards to determine medical necessity and follow specific guidelines for reviewing treatment requests. This law directly affects health insurance companies and their policyholders in Mississippi.