Scientists are not certain what causes attention deficit hyperactivity disorder, but studies suggest that genetics plays a role along with other factors such as nutrition, environmental issues and even brain injuries, explains Everyday Health. Scientists believe it is a combination of these factors that lead to the development of ADHD in some individuals.
ADHD is one of the most common neurodevelopmental disorders in childhood, as stated by the Centers for Disease Control and Prevention. The symptoms include impulsive behavior, difficulty paying attention, excessive daydreaming and hyperactivity.
There are many factors that are thought to cause ADHD, one of which is genetics, according to Everyday Health. Studies show people with ADHD often have another family member who has been diagnosed previously. Environmental factors can also play a role. Studies show exposure to cigarettes and alcohol during pregnancy significantly increases the risk of the child developing ADHD. Additional studies have been done on the use of food additives, pesticide use and artificial sweeteners on the effects on children and ADHD, which suggest that some children are more sensitive to these items than others.
Children who have had a brain injury may display similar behaviors to ADHD, but the number of children with a traumatic brain injury is rare, states the National Institute of Mental Health. It is not clear which of these is the biggest factors in causing ADHD, but likely it is a combination of several working together that determine if a child displays symptoms.