Attention-Deficit/Hyperactivity Disorder: Glossary

Attention Deficit Hyperactivity Disorder (ADHD): A developmental and behavioral disorder that is characterized by inattention, distractibility, hyperactivity, and impulsivity that is inappropriate for a person's age level

Attention Deficit Disorder (ADD): A label with the same meaning as ADHD. At one time, ADD referred to a disorder involving difficulty paying attention or focusing attention without hyperactivity.

Bipolar disorder: Mental condition that is marked by mood swings between periods of intense highs and lows

Clinical trial: Also called a research study; a research program involving patients with a particular condition

ADHD, Combined Type: Most common type of ADHD. People with this form show significant symptoms of inattention, hyperactivity, and impulsiveness.

ADHD, Predominantly Hyperactive-Impulsive Type: A form of ADHD in which people show both hyperactive and impulsive behavior, but may not show enough symptoms of inattention to qualify for Combined Type.

ADHD, Predominantly Inattentive Type: Type of ADHD formerly known as attention deficit disorder (ADD). People with this type of ADHD show significant symptoms of inattention and are not overly active or disruptive. Type of ADHD formerly known as attention deficit disorder (ADD). People with this type of ADHD show significant symptoms of inattention and are not overly active or disruptive.

Neural: Related to the nervous system.

Neurotransmitter: A chemical in the brain that transmits nerve impulses.

Nonstimulants: Medicines that help people with ADHD. One example of a nonstimulant medication for ADHD is Strattera.

Psychostimulants: Medicines that help people with ADHD to focus their thoughts and ignore distractions. Examples include Ritalin, Dexedrine, and Adderall.

Reviewed by the doctors at The Cleveland Clinic Children's Hospital (2005).