New research published in the Journal of Attention Disorders reveals a significant increase in the number of working-age adults in the United States who report having ever been diagnosed with attention-deficit/hyperactivity disorder, or ADHD. The study found that nearly 14% of adults between the ages of 18 and 64 reported a past diagnosis, a figure substantially higher than estimates from just over a decade ago. Researchers also uncovered notable differences in diagnosis rates across various demographic groups, including sex, age, race, education level, and where people live.