A couple of recent studies are taking a new look at the differences in adult and childhood ADHD.
They suggest that adult ADHD is not just a continuation of childhood ADHD, but that the two are different disorders entirely.
In addition, the researchers say that adult-onset ADHD might actually be more common than childhood onset.
The two studies used similar methodology and showed fairly similar results.
The first study, conducted by a team at the Federal University of Rio Grande do Sul in Brazil, evaluated more than 5,000 individuals born in the city of Pelotas in 1993. Approximately 9 percent of them were diagnosed with childhood ADHD — a fairly average rate. Twelve percent of the subjects met criteria for ADHD in adulthood — significantly higher than the researchers expected — but there was very little overlap between the groups. In fact, only 12.6 percent of the adults with ADHD had shown diagnosable signs of the disorder in childhood.
The second study, which looked at 2,040 twins born in England and Wales from 1994-5, found that of 166 subjects who met the criteria for adult ADHD, more than half (67.5 percent) showed no symptoms of ADHD in childhood. Of the 247 individuals who had met the criteria for ADHD in childhood, less than 22 percent retained that diagnosis into adulthood.
These reports support findings from a third study from New Zealand, published in 2015. Researchers followed subjects from birth to age 38. Of the patients who showed signs of ADHD in adulthood in that study, 90 percent had demonstrated no signs of the disorder in childhood.
While the results from these studies suggests that the widely accepted definition of ADHD – a disorder that develops in childhood, is occasionally “outgrown” as the patient ages- may need to be reassessed.
However, not everyone is on board with the recent findings. Some experts suggest that the study’s authors may have simply missed symptoms of ADHD in childhood in cases where it didn’t seem to become apparent until adulthood.
“Because these concerns suggest that the UK, Brazil, and New Zealand studies may have underestimated the persistence of ADHD and overestimated the prevalence of adult-onset ADHD, it would be a mistake for practitioners to assume that most adults referred to them with ADHD symptoms will not have a history of ADHD in youth,” write Stephen Faraone, Ph.D., and Joseph Biederman, M.D., in an editorial cautioning the ADHD community to interpret the two most recent studies with a grain of salt. They called the findings “premature.”
In both of these studies and in previous research, adult ADHD has been linked to high levels of criminal behavior, substance abuse, traffic accidents and suicide attempts. These troubling correlations remained even after the authors adjusted for the existence of other psychiatric disorders — proving once again that whether it develops in childhood or adulthood, untreated ADHD is serious business.
Both of the studies challenge conventional beliefs that childhood onset ADHD is more likely to continue into adulthood. Many experts would like to see more research on this topic to verify these findings
The two studies were published in the July 2016 issue of JAMA Psychiatry.
Story source: Devon Frye, http://www.additudemag.com/adhdblogs/19/12040.html