Dr. Nadeau helped expand the understanding of ADHD across the lifespan and was among the first leaders to bring attention to the experiences of women and girls with the condition.

Kathleen Nadeau, PhD, is a clinical psychologist and internationally recognized authority on ADHD. She has spent decades working to improve understanding and care for individuals with ADHD across the lifespan and in 2025 was presented with CHADD’s Lifetime Achievement Award. In 1999 she was inducted into the CHADD Hall of Fame with her colleague Patricia O. Quinn, MD. Dr. Nadeau founded the Chesapeake Center in Bethesda, Maryland, which was one of the largest ADHD clinics in the United States for many years before closing in 2026.

Dr. Nadeau has played a major role in expanding recognition of ADHD beyond the traditional focus on hyperactive boys. Beginning in the early 1990s, she helped bring attention to adult ADHD and the ways the condition persists across the lifespan. She later became a leading advocate for understanding ADHD in girls and women, coauthoring the groundbreaking book Understanding Girls with ADHD with Patricia Quinn, MD, and Ellen Littman, PhD. She also co-edited Understanding Women with ADHD and Gender Issues and ADHD: Research, Diagnosis, and Treatment, helping clinicians and researchers recognize how ADHD often appears differently in females and why many girls and women have historically gone undiagnosed.

In addition to her clinical leadership and advocacy, Dr. Nadeau is a prolific author and educator. She has written or coauthored more than a dozen books on ADHD, ranging from children’s guides such as Learning to Slow Down and Pay Attention to adult-focused works including ADD-Friendly Ways to Organize Your Life and her recent book Still Distracted After All These Years, which addresses the needs of older adults with ADHD. Through her work, she has trained generations of clinicians, educators, and families in understanding ADHD.