In this episode, I speak with Celine Saulnier, PhD, a clinical psychologist and co-author of the Vineland Adaptive Behavior Scales, Third Edition, about the evolving science and clinical practice of autism assessment and diagnosis. Celine shares her path from training with M-CHAT developer Deborah Fein, to nearly a decade at the Yale Child Study Center, to directing clinical research at Emory University and the Marcus Autism Center, and finally to founding her own practice. We discuss the two hallmark domains of autism, social communication differences and restricted or repetitive behaviors, and why no single measure can capture the conditions variability across verbal ability, cognitive functioning, and presentation. She describes groundbreaking eye-tracking research showing that divergence from typical social attention emerges as early as six months of age, and research has led to FDA approval of a diagnostic technology called EarliPoint to identify autism in child from this young age up to eight years old. We also discuss the genetics of autism in children, including recurrence risk for siblings and the concept of the “broader autism phenotype,” where family members show subthreshold traits (or shadow traits) that still warrant support. We discussed aspects of autism, including theory of mind, sensory processing differences, and repetitive behaviors, as well as the chronic anxiety, dysregulation, and burnout that can result from navigating a world not built for neurodivergent processing. Celine distinguishes between camouflaging and masking, and discusses how these coping strategies, while adaptive in the short term sense, can be associated with poor mental health outcomes over time. Finally, we explore the range of interventions available across the lifespan, from parent coaching and skill building in early childhood to social skills groups, executive functioning coaching, and life coaching in adulthood. Celine Saulnier, Ph.D., obtained her doctorate in Clinical Psychology from the University of Connecticut, after which she completed a postdoctoral fellowship and then joined the faculty at the Yale Child Study Center, Yale University School of Medicine. At Yale, Celine worked closely with Drs. Sara Sparrow and Domenic Cicchetti investigating adaptive behavior profiles in Autism Spectrum Disorders. She became the Training Director and then Clinical Director for the Yale Autism Program, specializing in diagnostic evaluations of individuals with autism and related disorders across the lifespan. In 2011, she relocated to Emory University School of Medicine and the Marcus Autism Center to help develop and direct a large-scale clinical research program. In 2018, she opened her own diagnostic clinic and consulting company, Neurodevelopmental Assessment & Consulting Services (www.nacsatl.com) in Decatur, GA. Celine remains an Adjunct Associate Professor at Emory University, and she conducts national and international trainings to professionals on autism and related disorders. For her teaching, she was awarded the New England Educational Institute Outstanding Educator Award for Mental Health Education. Celine is on the editorial board for the Journal of Autism and Developmental Disorders, the Scientific Advisory Board of the Autism Science Foundation, and an Emeritus member of the Atlanta Autism Consortium's Board of Directors. In addition to co-authoring the Vineland-3, Celine has published numerous articles in peer-reviewed journals, and she has written two books, Essentials of Autism Spectrum Disorders Evaluation and Assessment and Essentials of Adaptive Behavior Assessment of Neurodevelopmental Disorders.