ADHD is a neurodevelopmental disorder, meaning it affects the brain and nervous system. It affects children and adults, and the disorder is marked by problems with attention, impulse control and hyperactivity. A variety of causes, both genetic and environmental, are thought to be responsible for the condition.
Three types of ADHD exist. Predominately inattentive presentation makes organizing and paying attention difficult. Predominately hyperactive-impulsive presentation is marked by the inability to sit still and impulsivity. Those with combined presentation have symptoms from both categories. Diagnosis of ADHD is a multistage process that includes a medical exam to rule out other causes. Those with the disorder often have accompanying conditions such as anxiety.