Glossary | Attention Deficit Hyperactivity Disorder (ADHD)

Overview: 

ADHD is a condition that affects how people behave. People with ADHD might find it hard to concentrate, be very active, and act without thinking.

Symptoms: 

The main signs of ADHD are trouble paying attention, being very active (hyperactivity), and acting without thinking (impulsiveness).

Diagnosis: 

Doctors use special guidelines to check if someone has ADHD. They look at how a person behaves at home, school, and in other places.

Types: 

There are three main types of ADHD:

For more information on each type, please see our detailed ADHD types page.