With more than 20,000 members and 200 affiliates nationwide, CHADD is the nation’s leading nonprofit organization serving individuals with Attention-Deficit/Hyperactivity Disorder (AD/HD). Through collaborative leadership, advocacy, research, education and support, CHADD provides science-based, evidence-based information about AD/HD to parents, educators, professionals, the media and the general public. Local chapters in California are listed on this website.