Clinical trials are research studies that look at new ways to prevent, detect, or treat diseases and conditions, including ADHD. During clinical trials, investigated treatments might be new drugs or new combinations of drugs, new surgical procedures or devices, or new ways to use existing treatments. In many trials, some participants are randomly assigned to the “control” group and receive an inactive “placebo” treatment or a standard intervention currently in use; sometimes the control subjects are later given a chance to try the experimental treatment. The object is to be able to compare the effect of the experimental treatment with standard or no treatment. The goal of clinical trials is to determine if a new test or treatment works and is safe. Although individual participants may benefit from being part of a clinical trial, participants should be aware that the primary purpose of a clinical trial is to gain new scientific knowledge so that others may be better helped in the future.