Attention Deficit Hyperactivity Disorder (ADHD) is a condition that becomes apparent in some children in the preschool and early school years. It is hard for these children to control their behavior and/or pay attention. It is estimated that between 3 and 5 percent of children have ADHD, or approximately 2 million children in the United States.
Autism is a disorder of brain function that appears early in life, generally before the age of three. Children with autism have problems with social interaction, communication, imagination and behavior. Autistic traits persist into adulthood, but vary in severity. Some adults with autism function well, earning college degrees and living independently. Others never develop the skills of daily living, and may be incorrectly diagnosed with a variety of psychiatric illnesses. The cause is unknown.