As many as one in four U.S. students are misusing ADHD prescription drugs, according to new research. A study published on Tuesday found widespread misuse of drugs for attention-deficit and hyperactivity disorder. The study in JAMA Network found students used the medications without a doctor's prescription or for nonmedical reasons, and described  the results as "a major wake-up call." The findings were based on a survey of more than 200,000 students in 8th, 10th and 12th grades.