ADHD is one of the most common behavioral disorders, affecting approximately 5.4 million children in the United States. Between 2003 and 2007, the number of diagnosed cases of ADHD increased by 22 percent (CDC, 2011). Because all children sometimes display characteristics of ADHD (not sitting still, impulsive behavior, or not paying attention), there is concern that ADHD is being diagnosed in children when they are, in fact, simply immature for their age group.

ADHD and Other Disorders

Because some symptoms of ADHD are also common symptoms of other disorders, some children have been misdiagnosed with ADHD. For example, low energy and decreased motivation are also symptoms of depression. Hyperactivity is also a common symptom of bipolar disorder.

In a study at Emory University in Georgia that focused on comparing children with bipolar disorder, depression, and ADHD, researchers found that, in some cases, ADHD was overdiagnosed, while bipolar disorder was underdiagnosed (Chilakamarri et al., 2011).

However, according to a study conducted at Muhlenberg College in Pennsylvania that reviewed all existing research on how often ADHD is diagnosed, there is no conclusive evidence to support the theory that children are being overdiagnosed with ADHD (Sciutto & Eisenberg, 2007). False negatives (people with ADHD who are not diagnosed) outnumber false positives (people wrongly diagnosed with ADHD).

Age and ADHD

Age may play a role in the occasional misdiagnosis of ADHD. In a recent study published in the Canadian Medical Association Journal, researchers found that Canadian children who were younger than their classmates were more likely to be diagnosed with ADHD—boys were 30 percent more likely and girls were 70 percent more so (Morrow et al., 2012).

The cutoff date for enrollment in Canadian schools is December 31st, so researchers compared children who were born in January (the oldest in their classes) and December (the youngest in their classes). The study concluded that children born in December, who were younger than their peers, and thus less mature, were more likely to be diagnosed with ADHD.

Learn the Facts

There are conflicting opinions about the diagnosis and misdiagnosis of ADHD, which can be confusing for many patients. If you think you have ADHD, or if you have a child who has been diagnosed, the best course of action is to learn the facts—know what ADHD is and what it isn’t. Then, work with your doctor or pediatrician to determine the correct diagnosis, while exploring any other possible causes of ADHD symptoms. If you have children who are younger than their classmates, be sure to consider their ages and maturity levels.