ADHD is a complex disorder affected by a number of different factors. Causes and risks of ADHD interact to make some individuals more susceptible to the disorder than others. Differences in neurological function are widely accepted as the root cause of ADHD. However, environmental factors can also increase the likelihood of developing ADHD. Finally, individuals in certain groups — such as males and individuals with other behavioral disorders — experience increased risk of ADHD.

Biological Roots of ADHD

ADHD is influenced by biology and genetics; researchers have found that changes in the way the brain processes neurotransmitters play a role in ADHD. Neurotransmitters help send messages throughout the brain, and in cases of ADHD, problems with neurotransmitter activity can lead to behavioral changes. For example, the neurotransmitter dopamine works to activate the areas of the brain controlling attention and focus. Serotonin and adrenaline can also play a role in ADHD. Some individuals with ADHD show structural differences in certain areas in the brain.

In addition, genetics seem to play a role in the development of ADHD in children. ADHD appears to run in families; 25 percent of children with ADHD have a relative with the disorder (Mayo Clinic, 2009). Family studies, twin studies (in which twins with identical DNA are studied) and adoption studies have suggested that ADHD is more closely connected to biology than upbringing.

Environmental Effects

Some studies have found that exposure to certain toxins in the environment can increase a child’s risk of ADHD. Young children exposed to lead may have a greater chance of developing the disorder. Maternal exposure to toxins during pregnancy can have similar effects, as substances in a mother’s body can be transmitted to the fetus. Maternal smoking and illicit drug use can also affect ADHD risk.

Additional ADHD Risk Factors

Other conditions and characteristics are often found along with ADHD. These include:

  • Being a gifted learner or having a learning disability
  • Hyperthyroidism
  • Male gender
  • Premature birth.

Other behavioral or mood disorders frequently co-occur with ADHD. These include depression, anxiety and oppositional defiant disorder (ODD).

What Does Not Cause ADHD?

Teachers and parents often wonder what causes ADHD, and many theories and myths exist. For example, many people believe that excess sugar in a child’s diet can cause ADHD. No research has substantiated this claim. Parents do not cause ADHD by treating their children a certain way or employing certain methods of discipline. However, a child with ADHD can exhibit changes in behavior based on interactions with parents. A home life high in structure and regularity improves many children’s ADHD symptoms.


KidsHealth. (2010). ADHD. Retrieved August 11, 2010, from

Mayo Clinic Staff. (2009). Attention-deficit/hyperactivity disorder (ADHD). Retrieved August 11, 2010, from

Medline Plus. (2010). Attention deficit hyperactivity disorder (ADHD). Retrieved August 11, 2010, from

National Institute of Mental Health. (2008). Attention deficit hyperactivity disorder (ADHD). Retrieved August 11, 2010, from

 Posted on : June 14, 2014