Causes of ADHD

No single cause has yet been identified for ADHD. A number of risk factors have been noted, however, that affect a child’s brain development and behavior that acting in combination may lead to ADHD symptoms. They include

  • Genetic factors

  • Variations in temperament (a child’s individual differences in emotional reactivity, activity level, attention, and selfregulation)

  • Medical causes (especially those that affect brain development)

  • Environmental influences on the developing brain (including toxins such as lead, alcohol, and nutritional deficiencies)

Some research finds that children with ADHD may experience a delay in the normal maturing of their brain. Despite these many advances in research on the causes of ADHD, none of these findings are yet ready for use by physicians in making the diagnosis of ADHD.

Researchers are certain that ADHD tends to run in families. Close relatives of people with ADHD have about a 5 times greater than random chance of having ADHD themselves, as well as a higher risk for such common accompanying disorders as anxiety, depression, learning disabilities, and conduct disorders. An identical twin is at high risk of sharing his twin’s ADHD, and a sibling of a child with ADHD has about a 30% chance of having similar problems. Although no single gene has been identified for ADHD, research continues in this area, and it is likely that several genes will be found that contribute to ADHD symptoms. Brain imaging studies have found some differences in brain anatomy between children diagnosed with ADHD and those who have not been diagnosed, but no consistent pattern has yet emerged from these studies.

The fact that children and adolescents respond so consistently to stimulant medications, and that these medications influence biochemical systems in the brain, suggests that biochemical causes may contribute to ADHD symptoms as well. This remains an area of active research. In the next few years newer brain-imaging tools and more sophisticated genetic techniques will continue to shed more light on the processes underlying ADHD. Still, it is unlikely that a single cause will be identified.

ADHD Over Time

Attention-deficit/hyperactivity disorder is a complex disorder with different challenges arising at each new phase of a child’s development. Children who are at risk for developing ADHD generally carry some symptoms with them as early as preschool age and continuing throughout adolescence and even into adulthood. Attention-deficit/hyperactivity disorder is sometimes diagnosed in preschoolers, who display extremely high activity levels and impulsiveness. As a child grows into adolescence, his ADHD-associated behaviors may persist and become just as problematic as they were earlier in life. He may have difficulty concentrating, and be disorganized and easily distracted. Problems in adolescents with ADHD symptoms are likely to be expressed in different ways than they were in early childhood. Hyperactivity, for example, frequently takes center stage in early childhood but diminishes and may no longer be a problem by late adolescence or early adulthood. Inattention and impulsivity are likely to persist and can affect an adult’s educational experience, work life, and relationships. Learning disabilities that were present during childhood also continue to exist in later years, as can any emotional, behavioral, and social problems that have not been fully resolved.

At one time or another all children and adolescents with ADHD may face some challenges relating to family relationships, status among their peers, social skills, academic achievement, self-esteem, self-perception, and/or accidental injury. With help, however, children can learn to manage their symptoms in their early years as well as through adolescence and into adulthood. Early and accurate diagnosis is the first step toward organizing a plan that can make a difference to your child and your family.

As you begin to focus on the problems and issues that your child is facing, do not forget to appreciate and encourage his unique strengths and abilities as well, and to communicate that to him. A child with ADHD (like all other children) not only thrives on positive reinforcement and praise, but also desperately needs to know that his symptoms do not make him “bad,” “undisciplined,” “stupid,” or “lazy,” as is so often implied. Educating him about what ADHD is—and what it is not—will help him cope with whatever discouraging comments or self-doubts come his way. The more he understands, the greater are his chances of success.

Finally, children with ADHD frequently grow up to become successful and happy adults.


Last Updated



ADHD: What Every Parent Needs to Know (Copyright © 2011 American Academy of Pediatrics)

The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.