Attention Deficit Hyperactivity Disorder

Basics

Attention deficit hyperactivity disorder (ADHD) is a psychiatric disorder that begins in childhood, and is characterized by a persistent pattern of inattention, impulsivity, and hyperactivity. ADHD is one of the most commonly diagnosed psychiatric disorders in children and adolescents. ADHD is thought to affect about 9.2% of boys and 2.9% of girls who are of school age. While it is estimated that about 2% of adults also suffer from ADHD, the condition often goes unrecognized in adults.

People with ADHD have many symptoms, including extreme inattentiveness and/or impulsiveness and hyperactivity. Many people with ADHD continue to have symptoms throughout life.

Causes

ADHD runs in families, and seems to have a strong genetic component.

Scientists are not sure what happens in the brain to cause ADHD. One study found that children with ADHD have symptoms similar to those seen in adults with damage to the part of the brain largely responsible for emotions and personality (frontal lobes). Therefore, it is thought that the frontal lobes or related structures may be involved with ADHD [Figure 1]. Other studies evaluating blood flow or energy use in the brain have also found evidence of brain dysfunction among people with ADHD.

Figure 1. Frontal lobes of the brain

The frontal lobes are thought to be a point of origin for the symptoms of ADHD.