TX HB564

Removes the requirement that autism spectrum disorder must be diagnosed before a child's 10th birthday to qualify for insurance coverage, allowing coverage from the date of diagnosis regardless of age

Updates the definition of autism spectrum disorder to align with the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) or later editions, while still recognizing diagnoses made under previous editions including autism, Asperger's syndrome, and PDD-NOS

Requires health benefit plans to cover any "medically necessary" treatment for autism spectrum disorder, with detailed criteria defining medical necessity including services that address patient needs, prevent regression, maintain skills, and follow evidence-based clinical standards

Prohibits health plans from restricting healthcare practitioners from performing evaluations or limiting the settings where autism services can be provided, except where enrollees qualify for Medicaid reimbursement

Applies to health benefit plans delivered, issued, or renewed on or after January 1, 2026, with an effective date of September 1, 2025