How I evaluate a child for ADHD, and why I will not diagnose from a questionnaire alone

Every few weeks a parent arrives with a completed Vanderbilt rating scale from school, a teacher's note, and a clear expectation: the child has ADHD, please prescribe. Sometimes they are right. Often enough they are not, or they are only partly right, and the questionnaire cannot tell the difference. Here is how I actually evaluate a child, and why I will not make this diagnosis from a form.

What a questionnaire can and cannot do

Rating scales such as the Vanderbilt ADHD Diagnostic Rating Scale and the Conners scales are good at one thing: they tell me whether the adults around a child are seeing a lot of inattentive or hyperactive behavior. That is useful, and the American Academy of Pediatrics clinical practice guideline for ADHD recommends collecting them from parents and teachers. I ask for them before every evaluation.

What they cannot do is tell me why the behavior is there. The items on an ADHD scale describe behavior, not cause. "Has difficulty sustaining attention," "is easily distracted," "does not seem to listen." A child who is anxious scores high on those items. So does a child who is not sleeping, a child with an undiagnosed reading disorder, a child who is being bullied, a child whose parents are separating, and a child who is depressed. Several of these can coexist with ADHD, which is common. Several of them look exactly like ADHD and are not.

The DSM-5-TR criteria, which I use, require more than a symptom count. Symptoms have to have been present before age 12, they have to show up in two or more settings, and they have to cause real impairment. Most important, they must not be better explained by another condition. A questionnaire cannot check that last requirement. A clinician can.

Step one: the history, in two parts

My ADHD evaluation runs about an hour and starts with the parents. I want the developmental history: pregnancy and birth, language and motor milestones, temperament as a toddler, how daycare and preschool went. ADHD does not appear in fourth grade out of nowhere. If a child was calm and focused through second grade and fell apart in third, I am thinking about what changed in third grade, not about ADHD.

I ask about sleep in detail: bedtime, time to fall asleep, snoring, night waking, morning behavior. Obstructive sleep apnea and chronic short sleep both produce inattention and hyperactivity in children that resolve when the sleep problem is treated. I ask about family history, because ADHD runs strongly in families and so do anxiety, mood disorders and learning disorders. I ask what is happening at home.

Then I spend time with the child alone. With a six-year-old that may be play and a few questions. With a twelve-year-old it is a conversation. I am looking for how the child relates to me, whether attention holds when the topic is interesting, whether there is worry underneath the restlessness, whether there is sadness, and what the child says about school. Children often know exactly which subject is hard and why, and they will tell a stranger things they will not tell a parent.

Step two: the school's side

The AAP guideline asks for information from the school, and I take that seriously. Teacher rating scales are the start. I also want report cards going back several years, any standardized testing, and any psychoeducational evaluation the school has done. If a child has never been tested for a learning disorder and the inattention is concentrated in reading or math, I ask the school for an evaluation before I settle on ADHD. Under federal law, public schools must evaluate a child when a parent requests it in writing and there is reason to suspect a disability. Many parents do not know they can ask.

The pattern across settings matters. ADHD shows up at home, at school and at the soccer field. A child who is impossible in one classroom and fine everywhere else is telling me something about that classroom.

Step three: ruling out what else fits

Before I diagnose ADHD, I want to have considered and either ruled out or named each of the following, because they are the conditions I see most often misread as ADHD or sitting beside it:

• Anxiety disorders, including separation anxiety and generalized anxiety. Worried children fidget, cannot concentrate, and ask to leave the room.
• Depression, which in children often looks like irritability and loss of effort rather than sadness.
• Specific learning disorders in reading, writing or math.
• Sleep disorders, especially sleep apnea and insufficient sleep.
• Hearing and vision problems. I ask when the last screen was and I do not assume it was normal.
• Trauma and family disruption, which can produce hypervigilance that looks like distractibility.
• Autism spectrum disorder, which frequently co-occurs with ADHD and changes the treatment plan.
• Medical causes such as thyroid disease, absence seizures, and side effects of medications already prescribed.

Some of these require a referral: an audiologist, a sleep study, the school psychologist, the pediatrician for labs. I would rather delay a diagnosis by a month than medicate the wrong condition for a year.

What about computerized tests and brain scans?

Families sometimes ask about continuous performance tests on a computer or about imaging. The AAP guideline is direct: no single test, including computerized attention tests, EEG-based tools or brain imaging, is sufficient to diagnose ADHD, and none are required. I treat these as adjuncts at best. A full neuropsychological battery is valuable when I suspect a learning disorder or when the picture is complicated, but it is not the ADHD diagnosis. The diagnosis is a clinical one, made from history, observation, and information from more than one setting.

What I tell families at the end

At the end of the evaluation I give a clear answer in one of three forms. First, I believe this is ADHD, here is the type, here is what else is present, and here is what I recommend. Second, I do not believe this is ADHD, here is what I think it is, and here is the plan. Third, I am not sure yet, here is the information I need, and here is when we will meet again. The third answer is the one parents like least, and it is often the honest one.

If the answer is ADHD, treatment follows the child's age. For children under six, the first-line treatment in the AAP guideline is parent training in behavior management, not medication. For school-age children and teens, FDA-approved medication combined with behavioral and school supports has the strongest evidence, including the long-running Multimodal Treatment Study of ADHD. I discuss stimulant and non-stimulant options with every family, and that decision deserves its own conversation.

A questionnaire is where I start. It is never where I stop.

More from Dr. Williams

• Teen depression: what parents see first and what to do in the first two weeks2026-07-07
• College students and anxiety: a psychiatrist's guide to the first semester2026-08-04
• Stimulants, non-stimulants and the decision I make with every family2026-09-01

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