How Doctors Diagnose ADHD in Children

Medically Reviewed By William C. Lloyd III, MD, FACS
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There's no simple test to tell if a child has ADHD (attention deficit hyperactivity disorder). Instead, doctors base the diagnosis on information gathered over time.

Symptoms of ADHD usually start when a child is 3 to 6 years old. However, they can begin as late as age 12. For a doctor to rule that a child has ADHD, the child must have six or more symptoms of the condition. And, the child must have them for at least six months. ADHD is not a "snapshot" diagnosis. It may take multiple clinic visits to confirm the diagnosis.

Doctors use accepted guidelines to decide if a child has ADHD. These are listed in the American Psychiatric Association's Diagnostic and Statistical Manual. The most recent version is the fifth edition.
Doctors refer to this as DSM-5.A child's doctor may ask a mental health specialist to help with the diagnosis. These experts will also need to know what the child's parents have seen and what they think. Input from a child's teachers and caregivers is also important. All of this information will help the doctor make the diagnosis.

ADHD Diagnosis Using DSM-5

DSM-5 lists three main symptoms of ADHD:

  • Trouble staying focused and paying attention (inattention)
  • Trouble controlling behavior (impulsivity)
  • Being overly active (hyperactivity)

Symptoms of inattention include:

  • Being easily distracted or forgetful
  • Not being able to stay focused on one thing
  • Not listening
  • Not following instructions
  • Being disorganized
  • Avoiding tasks
  • Losing things

Symptoms of impulsivity or hyperactivity include:

  • Constant fidgeting or squirming
  • Inability to stay seated
  • Constant motion
  • Frequent running and climbing
  • Not being able to be quiet
  • Excessive talking
  • Frequent interrupting
  • Not waiting for a turn

What the Doctor Looks For

A child might not show signs of ADHD all the time. Also, ADHD is not the only disorder that can cause these symptoms. Because of that, doctors will also look for other conditions before diagnosing ADHD. These include:

  • When symptoms started: Many ADHD symptoms start before age 12.
  • Behavior differences: A child with ADHD will have symptoms above and beyond what other children of that age might have.
  • Where and when symptoms occur: They should occur in more than one place, such as at home and school.
  • Symptom severity: Symptoms should be bad enough that they keep the child from being able to function well.
  • Other possibilities: Whether anything else—physical or mental—could be causing the child’s behavior.

Types of ADHD

Doctors also try to figure out what type of ADHD a child has. The doctor bases this on symptoms. However, it's important to know this can change over time. There are three types:

  • Predominantly inattentive
  • Predominantly hyperactive-impulsive
  • Combined

The Bottom Line

Successful treatment of ADHD starts with a good diagnosis. It also helps when a child's parents have a good understanding of ADHD. The more you know, the better you can help your child move beyond the diagnosis and manage the condition.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Jul 29
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Attention Deficit Hyperactivity Disorder. National Institutes of Health. National Institute of Mental Health. 
  2. Attention-Deficit / Hyperactivity Disorder (ADHD): Symptoms and Diagnosis. Centers for Disease Control and Prevention.