But ADHD often continues into adulthood, multiple studies have now shown. The current estimated prevalence in adults is around 2.5 to 3 percent, compared with 5 to 6 percent in children. The 2013 edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) made it easier to diagnose adults, saying grown-ups can have five symptoms instead of the six required in children and acknowledging that ADHD might look different as people grow older. “They don’t climb on furniture and stuff like that,” Faraone says. (The DSM-5 still requires that some symptoms be present before the age of 12.) The first guidelines for diagnosing and treating ADHD in adults are now being developed by the American Professional Society of ADHD and Related Disorders.