ADHD: The Basics

Read our comprehensive guide to ADHD, including symptoms, subtypes and a detailed description of behaviors associated with ADHD.

Introduction

Attention-deficit hyperactivity disorder (ADHD) is a neurobehavioral disorder generally characterized by the following symptoms:

• Inattention
• Distractibility
• Impulsivity
• Hyperactivity

Types of ADHD

ADHD is classified into three subtypes:

• Predominantly Hyperactive-Impulsive Type. Behavior marked by hyperactivity and impulsivity, but not inattentiveness
• Predominantly Inattentive Type. Behavior marked by inattentiveness, but not hyperactivity and impulsivity
• Combination Type. A combination of hyperactivity/impulsivity and inattentive symptoms. This is the most common type of ADHD.

Childhood ADHD

In the United States, about 5.3 million children ages 3 - 17 have been diagnosed at some point with ADHD. This accounts for 8.6% of all American children in this age range. Symptoms of ADHD usually become apparent around age 7.

---

---

ADHD is sometimes described as impairing the “executive functions” of the brain. Executive functioning refers to the cognitive abilities necessary to plan, organize, and carry out tasks. Executive function deficits can cause the following problems:

• Inability to hold information in short-term memory
• Impaired organization and planning skills
• Difficulty in establishing and using goals to guide behavior, such as selecting strategies and monitoring tasks
• Inability to keep emotions from becoming overpowering
• Inability to shift efficiently from one mental activity to another

Hyperactivity. The term hyperactive is often confusing since, for some, it suggests a child racing around non-stop. A boy with ADHD playing a game, for instance, may have the same level of activity as another child without the syndrome. But when a high demand is placed on the child's attention, his brain motor activity intensifies beyond the levels of the other children. In a busy environment, such as a classroom or a crowded store, children with ADHD often become distracted and react by pulling items off the shelves, hitting people, or spinning out of control into erratic, silly, or strange behavior.