09/23/2025
FROM THE AMERICAN ACADEMY OF NEUROLOGY:
September 22, 2025
The Honorable Robert F. Kennedy, Jr.
Secretary
U.S. Department of Health and Human Services
200 Independence Avenue, SW
Washington, DC 20201
Dear Secretary Kennedy:
The AAN is the world’s largest association of neurologists and neuroscience professionals with
more than 40,000 members—and the leading voice in brain health. The AAN’s mission is to enhance
member career fulfillment and promote brain health for all. A neurologist is a doctor who specializes
in the diagnosis, care, and treatment of brain, spinal cord, and nervous system diseases. These
neurological diseases and disorders affect over one in three people worldwide and include autism
spectrum disorders, Alzheimer's disease, stroke, concussion, epilepsy, Parkinson's disease,
multiple sclerosis, headache, and migraine.
On behalf of our members, I write to provide feedback on the findings recently released by the
Department of Health and Human Services (HHS) concerning the causes of autism spectrum
disorders. The current body of research indicates that both genetic and/or environmental factors
may give rise to autism spectrum disorders. Determining exactly what causes autism spectrum
disorders requires further robust research. The AAN appreciates HHS’ longstanding commitment to
fostering fundamental scientific discoveries and their applications to protect and improve
neurological health.
Neurologists are experts in the field of autism spectrum disorders, and learning more about the
underlying causes of these broad conditions will help our patients and their caregivers. The AAN is
supportive of efforts across the federal government to better understand the underlying causes of
autism spectrum disorders. It is vital that the public rely on evidence-based guidance to have a clear
understanding of the causes of autism spectrum disorders and associated risk factors. The AAN and
other specialty societies use a rigorous evidence-based methodology when issuing clinical
guidelines or statements regarding the causes of neurological conditions. As experts in autism
spectrum disorders, we question whether the evidence presented by HHS reaches that standard.
The AAN is committed to working in support of the developing body of evidence related to the
factors that influence the development and diagnosis of autism spectrum disorders. The AAN uses a
transparent guideline development process informed by a systematic review of evidence and an
assessment of the benefits and harms of alternative care options. The AAN is unaware of a peer-
reviewed statement issued by a national provider or patient organization with expertise in the
diagnosis and treatment of autism spectrum disorders that supports the causal claims made by
HHS.
As you continue to focus on the causes of autism, the AAN hopes that you support robust
neuroscience research funding and that you consult relevant stakeholders, including professional
societies, patient groups, and research institutions to ensure that HHS is providing the most
accurate information. If you have any questions please don’t hesitate to contact Matt Kerschner,
Director, Regulatory Affairs and Policy, at mkerschner@aan.com. We look forward to working with
you on efforts to support people with autism spectrum disorders and their caregivers.
Sincerely,
Natalia S. Rost, MD, MPH, FAAN, FAHA
President, American Academy of Neurology
Send a message to learn more
