For most children with attention deficit hyperactivity disorder, or ADHD, the symptoms typically appear early in life. The National Institute of Mental Health estimates symptoms usually first appear between 3-6 years old. However, because there is a great degree of variability of the symptoms for each person, diagnosis can be difficult. The thin line between normal behavior for preschoolers and toddlers and symptoms of ADHD only increases the complexity and difficulty in making an accurate diagnosis.

Attention deficit disorder, or ADD, was removed from the Diagnostic and Statistical Manual of Mental Disorders in 1994. ADHD now stands alone as an independent diagnosis.

ADHD cannot be diagnosed based on the results of specific medical or blood tests. To make a diagnosis, your doctor will need to gather information about your child’s environment and behavior. This can include observations of the child’s demeanor, a detailed history offered by parents or teachers, and the results of psychological testing. During this evaluation, your child’s doctor will rule out other conditions that may have similar symptoms, including anxiety, depression, allergies, and difficulties with vision or hearing.

ADHD cannot be diagnosed based on the results of specific medical or blood tests.

Your child may also be referred to a mental health specialist for further evaluation. The specialist will likely observe the child’s behavior in a variety of situations. Some situations may be very structured, while others may require the child to pay attention for a period of time. Your child may be monitored in various social situations or given tests that determine intellectual ability or academic achievement.

For toddlers and preschoolers to be diagnosed with ADHD, they must display a combination of symptoms that are considered characteristic of the condition, including inattention, hyperactivity, and impulsivity. Specifically, the child must demonstrate six or more symptoms from these three categories before a diagnosis can be made.

To aid pediatricians and other health care professionals in making an accurate diagnosis of ADHD in children, the American Academy of Pediatrics has created specific guidelines. These include the following:

  • Symptoms occur in numerous settings, such as school, home or social events.
  • The symptoms make it challenging for the child to function normally in social settings, school or home.
  • The symptoms persist for a period longer than six months.
  • The symptoms are noticeable before the child is 7 years old.
  • The symptoms make it increasingly difficult for the child to complete schoolwork or interact with family and friends.
Reviewed by Dr. Sara Connolly, January 2019


  • Many children display the symptoms of ADHD between the ages of three and six.
  • Diagnosis is often difficult because it is hard to differentiate between normal behavior and the symptoms of ADHD.
  • To make a diagnosis, your child’s pediatrician will depend on a variety of information, including observing behavior, detailed history from parents and/or teachers and psychological testing.
  • To make an accurate diagnosis, the child must display at least six symptoms related to three primary categories: impulsivity, hyperactivity, and inattention.


  1. American Academy of Pediatrics. What You Need to Know About ADHD.
  2. Mayo Clinic. ADHD in Children.
  3. National Institute of Mental Health. Attention Deficit Hyperactivity Disorder.


  1. This is a great article that highlights the importance of following the American Academy of Pediatrics guidelines for diagnosis of ADHD.


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