A new study finds the rate of diagnoses for attention-deficit/hyperactivity disorder--or ADHD--among U.S. preschoolers has leveled off. At the same time, the prescribing rate of stimulant medications for these young patients has also stayed steady, a promising trend that researchers credit to treatment guidelines that were introduced in 2011. The guidelines were issued by the American Academy of Pediatrics. They called for a standardized approach to diagnosis, and recommended behavior therapy -- not drugs -- as the first-line therapy for preschoolers. But one child psychologist isn't convinced that the guidelines made a significant difference. Brandon Korman is a neuropsychologist at Nicklaus Children's Hospital in Miami. According to UPI, Korman bemoans the fact that psychological services have not been increased. He said the problem is twofold: Pediatricians aren't referring kids for behavior therapy, and too few qualified therapists are available to treat all the children who need help. Korman explained, "We need to make more of a collaborative effort between the medical folks and the behavioral health folks to come together to provide the best care for our kids." The study was published online Nov. 15th in the journal Pediatrics.