ADHD is one of the most prevalent neurodevelopmental disorders of childhood. It can continue well into the adult years.

ADHD is marked by:

• Inattention (wandering off task, loss of focus, disorganization)
• Hyperactivity (being in constant motion)
• Impulsivity (acting or speaking without thinking)

People with ADHD may have one of these signs or symptoms, or a combination. Most kids have the type of ADHD that’s a combo of symptoms.

More than 6 million children have been diagnosed with ADHD. Roughly 11 million people, or 5 percent of the adult population, have it, too according to a 2016 report from the Centers for Disease Control and Prevention (CDC).

Who Diagnoses ADHD?

ADHD can’t be diagnosed based on a 15-minute checkup. A proper ADHD diagnosis involves interviews with the person and their parents or other loved ones—and teachers, if applicable. There are checklists, observations, official questionnaires and a medical evaluation, too.

Before calling on a trained ADHD expert, know this: Only medical professionals, like physicians and nurse practitioners, can perform a thorough physical evaluation to rule out other possible medical causes of ADHD-like symptoms.

As part of a complete check-up, you or your child should get a vision and hearing test. Your physician may also screen for brain injuries, such as a concussion, and look for an underlying seizure or sleep disorder. In rare cases, individuals with ADHD-like symptoms may have thyroid dysfunction. If this is suspected, a blood panel may be ordered.

At the same time, other conditions can masquerade as—or coexist with—ADHD. These include:

• Developmental delays
• Autistic spectrum disorder
• Learning disabilities
• Anxiety
• Depression
• Trauma
• Bipolar disorder
• Obsessive-compulsive disorder

According to the American Academy of Pediatrics, the majority of children diagnosed with ADHD also meet the diagnostic criteria for another mental health disorder. These types of issues are normally screened for during the next step of the ADHD diagnosis process: The comprehensive evaluation (also called a comprehensive assessment).

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