A year-long experiment raises new doubts about the safety limits of one of the most popular artificial sweeteners.

ADHD stimulants may improve performance not by sharpening focus, but by making the brain more awake and motivated.

Prescription stimulants, such as Ritalin and Adderall, are widely used to treat attention deficit hyperactivity disorder (ADHD), including in children. In the U.S., about 3.5 million children aged 3 ...