Attention-deficit/hyperactivi... Health Article

Definition

Attention-deficit/hyperactivity disorder (ADHD) is a developmental disorder characterized by distractibility, hyperactivity, impulsive behaviors, and the inability to remain focused on tasks or activities.

Description

ADHD, also known as hyperkinetic disorder (HKD) outside of the United States, is estimated to affect 3%-9% of children, and afflicts boys more often than girls. Although difficult to assess in infancy and toddlerhood, signs of ADHD may begin to appear as early as age two or three, but the symptom picture changes as adolescence approaches. Many symptoms, particularly hyperactivity, diminish in early adulthood, but impulsivity and problems focusing attention remain with up to 50% of individuals with ADHD throughout their adult life.

Children with ADHD have short attention spans, becoming easily bored and/or frustrated with tasks. Although they may be quite intelligent, their lack of focus frequently results in poor grades and difficulties in school. Children with ADHD act impulsively, taking action first and thinking later. They are constantly moving, running, climbing, squirming, and fidgeting, but often have trouble with gross and fine motor skills and, as a result, may be physically clumsy and awkward. In social settings, they are sometimes shunned due to their impulsive and intrusive behavior.

Causes

The causes of ADHD are not known. However, it appears that heredity plays a major role in the development of ADHD. Children with an ADHD parent or sibling are more likely to develop the disorder themselves. Before birth, ADHD children may have been exposed to poor maternal nutrition, viral infections, or maternal substance abuse. In early childhood, exposure to lead or other toxins can cause ADHD-like symptoms. Traumatic braininjury or neurological disorders may also trigger ADHD symptoms. Although the exact cause of ADHD is not known, an imbalance of certain neurotransmitters(the chemicals in the brain that transmit messages between nerve cells) is believed to be the mechanism behind ADHD symptoms.

Symptoms

The diagnosisof ADHD requires the presence of at least six of the following symptoms of inattention, or six or more symptoms of hyperactivity and impulsivity combined:

Inattention:

• fails to pay close attention to detail or makes careless mistakes in schoolwork or other activities
• has difficulty sustaining attention in tasks or activities
• does not appear to listen when spoken to
• does not follow through on instructions and does not finish tasks
• has difficulty organizing tasks and activities
• avoids or dislikes tasks that require sustained mental effort (such as homework)
• is easily distracted
• is forgetful in daily activities

Hyperactivity:

• fidgets with hands or feet or squirms in seat
• does not remain seated when expected to
• runs or climbs excessively when inappropriate (in adolescents and adults, feelings of restlessness)
• has difficulty playing quietly
• is constantly on the move
• talks excessively

Impulsivity:

• blurts out answers before the question has been completed
• has difficulty waiting for his or her turn
• interrupts and/or intrudes on others

Further criteria to establish a diagnosis also require that some symptoms develop before age seven, and that they significantly impair functioning in two or more settings (home and school, for example) for a period of at least six months.

Many individuals with ADHD have symptoms from all three of the above categories. Some children, however, have behavior patterns in which inattention dominates, or hyperactivity and impulsivity dominate. For this reason, ADHD can be further categorized, or subdivided, into three subtypes. Children who have at least six symptoms from both of the inattention and hyperactivity-impulsivity categories above may be diagnosed with ADHD, combined type. Children who meet the symptom criteria for inattention, but not for hyperactivity/impulsivity are diagnosed with attention-deficit/hyperactivity disorder, predominantly inattentive type, commonly called ADD. Children who experience more symptoms from the hyperactivity and impulsivity categories, but fewer than six symptoms of inattention may be diagnosed with ADHD, predominantly hyperactive-impulsive type.