However, medication should never be used as the first line of defense, says Lawrence Diller, M.D., author of Should I Medicate My Child? There's concern that these drugs may bring about such side effects as sleeplessness and, in some cases, sudden emotional outbursts. "Psychiatric medicine in a preschooler must be used with extreme caution," says Dr. Diller. "There aren't even standardized guidelines for kids under five."
Before you consider medication, consult a child-development specialist, as well as your child's pediatrician, her caregivers, and especially her teachers if she's in nursery school or preschool. The school's program should reflect her needs. And try behavioral intervention first: Use immediate, tangible incentives for good behavior (such as extra time at the park) and time-outs as needed.
"Kids this age are so malleable that it often works wonders if parents are taught how to intervene at appropriate moments," says Dr. Diller. Of course, there are exceptions: "There is a small minority for whom medicine makes all the difference."