Homesickness is a normal part of growing up, says Chris Thurber, PhD, a clinical child psychologist with the Phillips Exeter Academy in Exeter, New Hampshire. In fact, Thurber's research indicates that during a two-week stay at camp, 90% of children will feel homesick at least one day.

In one study, Thurber asked children ages 8-16 at a two-week camp to rate their feelings of homesickness every day on a scale of zero to 10, with 10 indicating the most homesick. Results showed that about 20% of the kids exhibited moderate to severe levels of homesickness. Those kids were bothered enough by homesickness to have to do something to cope with it. Only 6% or 7% experienced intense levels of homesickness with severe symptoms like depression .

"Homesickness is a universal phenomenon, and it's developmentally normal," Thurber says. "Wouldn't it be odd if kids didn't miss home?"

So what exactly is homesickness? According to Thurber, "It's distress or impairment that's caused by an actual or anticipated separation from home and characterized by acute longing and preoccupying thoughts of home and attachment objects."

Distress or impairment, Thurber says, often shows up as emotional stress, such as sadness or anxiety . For some kids, it may also be manifested in behavior. They may be withdrawn and have trouble enjoying activities they used to like. In rare situations, kids may even exhibit physical symptoms like stomach aches or headaches.

Thoughts of home and attachment objects, like a pet, home cooking, even television, make it hard for children to enjoy themselves when they're away from home. What children miss most varies, says Thurber.

Younger children run the highest risk of suffering from severe symptoms of homesickness simply because they haven't developed coping skills for being away from home, Thurber says. That doesn't mean, though, that 13 and 14 year olds won't experience homesickness.

Also, contrary to popular belief, homesickness doesn't always disappear after the first few days of being away. Adults used to think that if kids made it through the first two or three days of camp, homesickness would subside. Thurber's research demonstrates the opposite.

Of the 20% of children who were the most homesick during a two-week camp, levels of homesickness increased throughout the week. They became more homesick until day 12 when they knew they'd soon be leaving. "This means that you can't ignore kids after the first three days of camp," Thurber says. "Nor can you ignore them if they're older."

Fortunately, parents can do things to ease a child's anxiety about going away from home, whether to camp, a friend or relative's house, or even a hospital. Sarah Fallon, a child care specialist with the Texas Children's Hospital in Houston, Texas, recommends preparation and practice. "The less surprises there are, the better," she says. "Parents should prepare children for what lies ahead."

Or says Susan Nathanson, owner and former camp director of Camp Matoaka in Smithfield, Maine, and author of The Homesick Manual , "It's not about preparing for camp, but preparing to deal with new situations."

The good news is that homesickness goes away with time. Nathanson says that only 1%-2% of her campers who were homesick the first year experience homesickness the next year.

So how can you help your kids prepare before they leave home? Follow this advice:

• Make it a joint decision.
• "If kids feel forced to go away, they tend to be more homesick," says Sal Severe, PhD, a school psychologist in Arizona and author of How to Behave So Your Children Will, Too . Let them help you decide how long they'll be away from home.
• Be positive.
• Don't let kids know that you're concerned about their ability to go away. "Resolve any concerns about your child privately," Nathanson says. Also, if you had a bad camp experience when you were young, don't talk about that with your child. Thurber advises saying things like, "I'll miss you, but we'll see each other soon. I know you'll be writing me lots of letters because of all the fun things you're going to do."
• Tell them it's normal to miss home.
• Explain that you miss home, too, when you're away. "Remembering that there's a positive side to feeling homesick makes kids feel better," Thurber says, adding that this is particularly important for older children who don't have as much experience being away from home as other children their age.
• Use the buddy system.
• Consider sending kids to the same camp as friends or siblings, Fallon says.
• Don't bribe children to go away.
• Bribing sends the wrong message to kids. "Time away from home is empowering and should be inherently rewarding," Thurber says. "It's what enhances independence and increases kids' self-esteem ."
• Plan going-away rehearsals.
• Severe recommends starting with one night away from home and then building up to a weekend.
• Don't send mixed messages.
• "Don't give kids mixed messages," Thurber says. For example, avoid saying that even though you know they're going to have a great time, you don't know what you'll do without them. "Monitor what you say so you don't give kids more reasons to worry," he says.
• Be creative.
• Give your kids creative strategies for dealing with homesickness, Thurber says. By giving them ways to work through their feelings, you'll get them through these tough times.
• Don't make "pick-up deals."
• Don't promise to pick your child up if homesickness strikes. Nathanson explains that if you've promised to pick up a child after three days, for example, the child will do nothing but wait for that day to arrive and never try to enjoy herself. "There are cases where homesickness is so severe that it's not right to make that child stay," says Thurber. By making her stay, you only sour her to the idea of going away from home. Yet those cases are rare, less than 1% of kids, he says.
• Prepare yourself.
• Make sure you're not giving off negative vibes, because kids feed off of their parents' vibes. If you're the type who gets emotional when saying goodbye, make sure you're with another adult who can be excited for the child.

Except for the small percentage of children who exhibit severe signs of homesickness, most will be very excited that they were able to lick their homesickness, Thurber says. "Their self confidence gets a boost because they made it through an uncomfortable, somewhat painful experience," he explains.