If your little one bursts into tears when you leave the room, that's normal. But if she sobs for hours and says, "I know you're not going to come back" or "What if you get hit by a car?" she may have separation anxiety disorder, which strikes about 4 percent of children, according to the Anxiety Disorders Association of America (adaa.org). Other symptoms include panic attacks, nightmares, depression, and refusing to go on playdates, to school, or to sleep in his own bed. The child might experience stomachaches, nausea, even vomiting, and say, "I'm so sick, don't leave."

"It can be extremely exhausting for the parents because it starts to interfere with life in other ways," says child psychologist Sara Abbot. "The kids don't want to get involved in activities outside the home, and the parents don't get any privacy."

In the past, pediatricians might have shrugged off these symptoms as a phase kids will grow out of. But research now suggests that anxiety disorders in childhood, if left untreated, can continue into adolescence and beyond. Early treatment can help prevent future problems. For a child to receive a diagnosis of separation anxiety disorder, the symptoms must persist for at least four weeks. But if your child is extremely anxious, tell your pediatrician sooner if you're concerned. He may refer your child for cognitive-behavioral therapy, which teaches children the skills to face their fears and calm themselves. The goals are to reinforce the notion that the world is safe, give themsome sense of control, and improve self-esteem, says Abbot. Treatment is often concentrated within a short period (weeks or months as opposed to years), and play therapy is often used with the youngest kids.

Feel-good reads
A few great books to ease the pain of goodbyes:

Mommy, Don't Go, by Elizabeth Crary
Will You Come Back for Me? by Ann Tompert
I Don't Want to Go to School, by Nancy Pando
The Kissing Hand, by Audrey Penn
I Love You All Day Longby Francesca Rusackas