HERE’S a paradox. Why does an amphetamine-like stimulant have a calming effect on children with attention deficit hyperactivity disorder (ADHD)?
Experiments with rats may have provided the answer. It seems that methylphenidate – better known as Ritalin and commonly used to treat ADHD – pulls off two apparently contradictory feats. First it raises levels of the neurotransmitter noradrenalin, which probably helps sharpen senses, and at the same time it dulls the brain’s reactions to unwanted distractions.
“It probably helps the animal focus on what’s new and not be distracted by what’s familiar,” says Candice Drouin, who led the team at Drexel University in Philadelphia. “That’s what happens in…
