Once an an adult with ADHD, always an adult with ADHD? Not necessarily. There’s some new research out suggesting that adults with ADHD can experience improvements in their symptoms. The study, from researchers in Brazil, tracked the symptoms of 344 adults with ADHD over the course of seven years. They found that on average, the adults’ symptoms declined with age...For others, though, it turns out that ADHD symptoms can also get worse.