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.
  • Maternal factors, such as:    
  • Smoking during pregnancy
  • Preterm labor
  • Exposure to certain environmental toxins, such as polychlorinated biphenyls (PCBs)
  • Childhood exposures to environmental toxins, such as lead, which is found in pipes or paint in older buildings
  • Premature birth
  • Overall parental health—A child may be at a higher risk of ADHD if their parent has certain conditions, such as alcohol use disorder or conversion disorder.
  • Other factors that may increase the risk of ADHD include:

        
  • Head injury at a young age (less than 2 years old)
  • Being born with a serious heart condition
  • Having Turner syndrome (a genetic condition)
  • Being exposed to certain pesticides
  • Spending over 2 hours a day watching TV or playing video games when young