A risk factor is something that increases your likelihood of getting a disease or condition.

It is possible to develop ADHD with or without the risk factors listed below. However, the more risk factors you have, the greater your (or your child’s) likelihood of developing ADHD.

Risk factors include:

  • Gender—Boys are more frequently diagnosed with ADHD than girls.
  • Heredity—ADHD and similar disorders tend to run in families, suggesting there may be a genetic component. People with a parent or a sibling, especially an identical twin, with ADHD are at increased risk of developing the condition.
  • Age—Symptoms typically appear in young children aged 3-6 years old.
  • Prenatal factors—Having a mother who smoked cigarettes and/or drank alcohol during pregnancy can increase a child's risk of ADHD. Being born prematurely may increase the risk, as well.
  • Parents' health—A child may be at a higher risk of ADHD if his parent has certain conditions, such as alcoholism and conversion disorder.

Research is ongoing into the connection between ADHD and other factors, such as:

  • Low birth weight
  • Brain injury (due to trauma, infections, tumors)
  • Toxic exposures