Why Do Some People Continue to Have ADHD as Adults and Others Do Not?

Health Writer

One of the mysteries surrounding ADHD is that some people seem to overcome or outgrow symptoms in adulthood while others do not and continue to struggle with symptoms throughout their life. In the most recent information from the Centers for Disease Control and Prevention show that 11 percent of children between the ages of 4 and 17 years old have been diagnosed with ADHD. In adults, that number drops to 8.1 percent. This is sometimes attributed to the fact that many adults are never diagnosed and struggle with undiagnosed ADHD, thinking their forgetfulness or inattentiveness is simply part of their personality, not a medical condition.

Until the 1990's, ADHD was considered a childhood disorder. Children and adolescents treated for ADHD were expected to grow up, mature, and outgrow the symptoms. Many were taken off medication before or during the high school years and very few continued on medication when they became adults. The adolescents who stopped medication once again struggled with symptoms, both socially and academically.

It wasn't only teens that noticed ADHD symptoms continuing - parents did too. As children were diagnosed and parents researched and learned about ADHD, they realized that some of their struggles could be attributed to ADHD. It was finally accepted that ADHD didn't go away. For many people, the symptoms continued into adulthood causing problems in relationships and careers.

But, there are some adults who were diagnosed with ADHD and after puberty find that their symptoms diminish. They no longer need treatment. According to the American Academy of Family Physicians, about one-third of children diagnosed with ADHD no longer fit the criteria as adults.

Recent research provides some clues. Previous research has shown that the cortex (a layer of tissue surrounding the outmost portions of the brain) is thinner in individuals with ADHD. Scientists, led by Dr. Philip Shaw, at the National Human Genome Research Institute recently concluded a long-term study on the development of the cortex in those with ADHD. Participants went through imaging scans over a number of years. At the start of the study, the average participant was 11 years old; at the conclusion of the study, the average was 23 years old. There were 92 participants who were diagnosed with ADHD and 184 who did not have ADHD.  Of those diagnosed with ADHD, 40 percent continued to have symptoms in adulthood.

The scientists found that when the cortex developed and thickened, symptoms of ADHD diminished. Those participants who continued to have symptoms of ADHD did not show any significant changes in the cortex. The study found that the number of symptoms directly correlated with the rate of thinning of the cortex.

The study offers some interesting information. It tells us that some people do indeed overcome ADHD symptoms and that others continue to have biological and physical signs that ADHD is present through the adult years. But, the study also leaves unanswered questions. Why do some people overcome ADHD? What causes the cortex to thicken in some people but not in others? And, does this information give us ways to better treat ADHD? Sr. Shaw, the lead researchers admits that further research is needed to explore these questions but believes this study is an important step in better understanding and predicting who will continue to show signs of ADHD as adults.


"Trajectories of Cerebral Cortical Development in Childhood and Adolescence and Adult Attention-Deficit/Hyperactivity Disorder," 2013, Philip Shaw at el, Biological Psychiatry