Attention deficit hyperactivity disorder (ADHD) is usually diagnosed in children. However, a few new studies show that, although the symptoms would be different, there is a possibility to develop ADHD in adulthood, too.

“Although the nature of symptoms differs somewhat between children and adults, all age groups show impairments in multiple domains – school, family and friendships for kids and school, occupation, marriage and driving for adults,” explained Stephen Faraone, a psychiatry researcher at SUNY Upstate Medical University in Syracuse, New York and author of an editorial accompanying the two studies in JAMA Psychiatry.

The study from Brazil tracked more than 5,200 people born in 1993 until they were 18 or 19 years old. By the end of the study, 492 participants, or 12.2%, met all the criteria for young adult ADHD except the age of diagnosis. The study also discovered that adult-onset ADHD is more common among female.

Another similar study focused on 2,040 twins born in England and Wales in 1994 and 1995. During childhood, 247 of them met the diagnosis criteria for ADHD. Amongst them, 54 still met the diagnosis criteria for the disease at age 18.

While ADHD in children results in hyperactivity, “ADHD amongst adults may have less obvious symptoms like being forgetful or having difficulty concentrating," remarked senior study author, Louise Arseneault of King’s College in London. “And if adults do experience hyperactive symptoms, these symptoms may manifest more as feelings of internal restlessness rather than obvious hyperactive behaviour like running or climbing around in inappropriate situations,” she added.

While ADHD in children causes hyperactivity, ADHD in adults causes problems like difficulty in concentrating.
While ADHD in children causes hyperactivity, ADHD in adults causes problems like difficulty in concentrating.

Yet, new study suggests otherwise

Despite the two findings confirming ADHD amongst adults, a newer study discovered that it is impossible for adults to develop ADHD.

According to a new research by Florida International University (FIU) clinical psychologist Margaret Sibley, more than 80% of people diagnosed with adult-onset ADHD probably don't have ADHD at all; instead already have them during childhood but were undiagnosed.

"We found a number of people who looked like they had adult-onset ADHD; but, when we looked closely, adult-onset symptoms were traced back to childhood or were better explained by other problems, like the cognitive effects of heavy marijuana use, psychological trauma, or depressive symptoms that affect concentration," elaborated Sibley.

The research assessed 239 participants every two years – starting at the age of 10 – and ending when the participants were 25. They used parent, teacher, and self-reports of ADHD symptoms, impairment, substance use, as well as other mental disorders – and looked at the context of the symptoms and the timing.

The study found that 24 of the youngsters would go on to develop attention deficit problems much later on, during high school or after. ADHD is often diagnosed between the age of five and 12. Going more in-depth with the research, they found that out of the 24 that developed onset-ADHD, five cases most likely stemmed from other causes, such as marijuana use, depression or anxiety, whereas the others are caused by attention deficits.

“This suggests to me the diagnosis doesn’t exist independent of a compelling psychiatric history,” said Dr Sibley. “No one in our group developed ADHD in adulthood out of nowhere.”

The possibility remains still

Dr Sibley may have presented a strong case; yet, not all experts agree to it.

“When we take out all those people who have complicating problems, like substance use and mood disorders, we still find that about a third of late-onset cases remain,” highlighted Jessica Agnew-Blais, a post-doctoral research fellow at the Institute of Psychiatry, Psychology and Neuroscience at King’s College London.

Her previous study estimated the prevalence of adult-onset ADHD is at about 6%. “What this discrepancy points to is that it’s important to look at different populations,” explained Dr Agnew-Blais of the new findings.

In fact, a lot more studies are emerging in relation to adult onset-ADHD. A study that aimed at determining whether there are differences among the referral, diagnosis, and treatment paths of adults with ADHD in psychiatric care and primary care, concluded that ADHD in adults is a common problem, but is more likely to be diagnosed and treated by psychiatrists. The study also revealed that only a minority of these patients have actually been diagnosed in childhood, while the rest continues to seek treatment.

“I don’t think clinicians should be shutting the door, if the only sticking point is the age of onset of symptoms,” echoed Blais. MIMS

Read more:

Study finds that ADHD patients can benefit from exercise
Lifestyle modification and behavioural intervention recommendations in treating ADHD
Late-onset ADHD identified; symptoms unique in adults