Dec. 8, 2003 -- Ritalin use in preteen children may lead to depression later in life, studies of rats suggest. It's an open question whether what passes for depression in lab rats has anything to do with depression in humans. But early use of Ritalin and other stimulant drugs seems to permanently alter animals' brains. That raises concerns that the same thing might be happening in children who take these drugs for attention deficit hyperactivity disorder (ADHD). The findings come from a research team led by William A. Carlezon Jr., PhD, director of the behavioral genetics laboratory at McLean Hospital...