ADHD Basics
Attention deficit hyperactivity disorder (ADHD) is a mental disorder that causes above-normal levels of hyperactive and disruptive behaviors. P...

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Attention deficit hyperactivity disorder (ADHD) is a mental disorder that causes above-normal levels of hyperactive and disruptive behaviors. People with ADHD tend to have difficulty concentrating, sitting still, paying attention, staying organized, following instructions, remembering details, and/or controlling impulses. One of the unfortunate complications for people with untreated ADHD is that they often have trouble getting along with their peers, family members at home, and coworkers.

For children, ADHD is perhaps most associated with problems at school. Children with ADHD often have difficulty succeeding in a controlled classroom setting; assignments become difficult obstacles, instead of productive learning experiences. Perhaps because of this—although it affects people of all ages—ADHD is more commonly diagnosed in children than in adults: A 2006 survey conducted by the Centers for Disease Control and Prevention (CDC) found that ADHD affects about four to six percent of American children ages five to 17 (approximately 4.5 million overall), making ADHD one of the most common childhood disorders in the United States. The survey also found that boys are twice as likely to be diagnosed as girls. The majority (50 to 70 percent) of these children will retain symptoms into adulthood, but many get better over time.  

Unfortunately, ADHD can be difficult to diagnose, and many children who suffer from the condition are labeled simply as troublemakers, problem children, or, even worse, stupid or lazy.  ADHD is, however, a real and serious condition, not a means of explaining away behavioral problems. Luckily, with an early diagnosis and proper treatment, children with ADHD can be just as successful as children who do not have the condition.

Types of ADHD

There is a wide range of behaviors that are symptomatic of ADHD. To make it easier to diagnose and treat, they have been grouped by the Diagnostic and Statistical Manual of Mental Disorders into three categories: inattentive behavior, above-normal activity level (hyperactivity), and lack of impulse control. Children who suffer from ADHD will display behaviors in one, two, or all three of these categories. Therefore, when diagnosing ADHD, the condition is divided into three subtypes:

Predominantly Inattentive Type

This is a form of ADHD that used to be known as attention deficit disorder, or ADD. As the name suggests, children with this type of ADHD have extreme difficulty paying attention, focusing, finishing tasks, and following instructions. Experts also think that many children with an inattentive form of ADHD may be overlooked because they don’t tend to disrupt the classroom. This form is most common among girls with ADHD. 

Predominantly Hyperactive-Impulsive Type

Children with this type exhibit primarily hyperactive and impulsive behavior such as fidgeting, interrupting, and an inability to wait their turns. Although inattention is less of a concern with this type of ADHD, predominantly hyperactive-impulsive patients may still have some problems focusing on tasks.

Combined Hyperactive-Impulsive and Inattentive Type

This is the most common type of ADHD. Children with this combined form of ADHD display a significant number of symptoms connected to all three behavioral categories—an inability to pay attention, a tendency towards impulsiveness, and above-normal levels of activity and energy.

Adult ADHD

Adults with ADHD have typically had the disorder since childhood, but it may not have been diagnosed until later in life; an evaluation usually occurs at the prompting of a peer, family member, or coworker who has observed problems at work or in relationships. Adults can be diagnosed with any of the three subtypes of ADHD discussed above. However, due to the relative maturity and experience of adults, as well as physical differences between adults and children, adult ADHD symptoms can be somewhat different than those experienced by children. For example, adults with predominantly hyperactive-impulsive ADHD are unlikely to run and jump around. Generally, ADHD has a less severe profile in adults than in children, but there is still some debate about accurately diagnosing adult ADHD. Learn more about adult ADHD.

Written by: the Healthline Editorial Team
Edited by:
Medically Reviewed by: Stephanie Burkhead, MPH
Published: Jul 29, 2010
Published By: Healthline Networks, Inc.
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