ADHD Diagnosis in Kids

Q: How Young Can ADHD Symptoms Be Diagnosed? Is It More Difficult to Diagnose in Girls?

Most ADHD medications are not approved for patients younger than 6, but that doesn’t mean symptoms aren’t present in kindergarten, preschool, or even earlier. If your toddler is a danger to himself or herself, or impacts your family’s overall health, an assessment may be appropriate as young as 2 years old.

Little boy climbing a tree.

Q: How young can ADHD symptoms be diagnosed? Is it more difficult to diagnose in girls?

A: Yes, you can diagnose and treat attention deficit disorder (ADHD or ADD) in children as young as 2. These are the children who present safety issues and struggle with behavior management. In my clinic, these young children are typically extremely impulsive and hyperactive. Their potentially dangerous and self-destructive behaviors include:

  • Jumping from high places without realizing that they could seriously hurt themselves
  • Running in parking lots
  • Preventing others from sleeping when they cannot fall asleep

[Self-Test: Could Your Child Have Hyperactive or Impulsive ADHD?]

The federal government funded a study called the Preschool ADHD Treatment Study1, which assessed young children with ADHD ages 3 to 5.5. Children were enrolled in behavior therapy sessions and parents participated in parent-training programs. Children whose symptoms did not improve after behavior therapy were treated with methylphenidate, which resulted in significant reductions of ADHD symptoms.

Diagnosing young girls can be more complicated than diagnosing boys of the same age. Some girls can be just as disruptive and have as many behavior difficulties as boys, but it is rare. More often, they present inattentive ADHD symptoms that are written off as depression or other mood disorders later in life.

The incidence of ADHD diagnosed in girls compared to boys is around 2 to 5, but the incidence in women and men is surprisingly equal. What this tells us is that many young girls’ symptoms are not noticed until they grow up and pursue a diagnosis on their own. One explanation for this could be that girls make less trouble for their parents and teachers than do boys; it is often the hyper children who get noticed first.

This content came from the ADDitude webinar by Thomas E. Brown, Ph.D., titled “A Careful Diagnosis: Expert Guidelines for Getting an Accurate ADHD Evaluation.” That webinar is available for free replay here.

Thomas E. Brown, Ph.D., is a member of ADDitude’s ADHD Medical Review Panel.

[How Is ADHD Diagnosed? Your Free Guide]


New York State Psychiatric Institute, National Institute of Mental Health. Treatment of Attention-Deficit/Hyperactivity Disorder in Preschool-Age  Children.  U.S. National Library of Medicine. (Jul. 2001)

Updated on November 14, 2019

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