What Is ADHD? (continued)

First, your child's doctor will take a medical history by performing a physical examination and asking you about any concerns and symptoms, your child's past health, your family's health, any medications your child is taking, any allergies your child may have, and other issues.

The doctor may also check hearing and vision so other medical conditions can be ruled out. Because some emotional conditions, such as extreme stress, depression, and anxiety, can also look like ADHD, you'll fill out questionnaires to help rule them out.

You'll be asked many questions about your child's development and behaviors at home, school, and among friends. Other adults who see your child regularly (like teachers, who are often the first to notice ADHD symptoms) probably will be consulted, too. An educational evaluation, which usually includes a school psychologist, may also be done. It's important for everyone involved to be as honest and thorough as possible about your child's strengths and weaknesses.

Causes of ADHD

ADHD is not caused by poor parenting, too much sugar, or vaccines.

ADHD has biological origins that aren't yet clearly understood. No single cause has been identified, but researchers are exploring a number of possible genetic and environmental links. Studies have shown that many kids with ADHD have a close relative who also has the disorder.

Although experts are unsure whether this is a cause of the disorder, they have found that certain areas of the brain are about 5% to 10% smaller in size and activity in kids with ADHD. Chemical changes in the brain also have been found.

Recent research also links smoking during pregnancy to later ADHD in a child. Other risk factors may include premature delivery, very low birth weight, and injuries to the brain at birth.

Some studies have even suggested a link between excessive early television watching and future attention problems. Parents should follow the American Academy of Pediatrics' (AAP) guidelines, which say that children under 2 years old should not have any "screen time" (TV, DVDs or videotapes, computers, or video games) and that kids 2 years and older should be limited to 1 to 2 hours per day, or less, of quality television programming.

Related Problems

One of the difficulties in diagnosing ADHD is that it's often found in conjunction with other problems. These are called coexisting conditions, and about two thirds of kids with ADHD have one. The most common coexisting conditions are:

Oppositional Defiant Disorder (ODD) and Conduct Disorder (CD)

At least 35% of kids with ADHD also have oppositional defiant disorder, which is characterized by stubbornness, outbursts of temper, and acts of defiance and rule breaking. Conduct disorder is similar but features more severe hostility and aggression. Kids who have conduct disorder are more likely to get in trouble with authority figures and, later, possibly with the law. Oppositional defiant disorder and conduct disorder are seen most commonly with the hyperactive and combined subtypes of ADHD.

Mood Disorders

About 18% of kids with ADHD, particularly the inattentive subtype, also experience depression. They may feel inadequate, isolated, frustrated by school failures and social problems, and have low self-esteem.

Anxiety Disorders

Anxiety disorders affect about 25% of kids with ADHD. Symptoms include excessive worry, fear, or panic, which can also lead to physical symptoms such as a racing heart, sweating, stomach pains, and diarrhea. Other forms of anxiety that can accompany ADHD are obsessive-compulsive disorder and Tourette syndrome, as well as motor or vocal tics (movements or sounds that are repeated over and over). A child who has symptoms of these other conditions should be evaluated by a specialist.

Learning Disabilities

About half of all kids with ADHD also have a specific learning disability. The most common learning problems are with reading (dyslexia) and handwriting. Although ADHD isn't categorized as a learning disability, its interference with concentration and attention can make it even more difficult for a child to perform well in school.